ArticlePDF Available

A Comprehensive Review on Structural Topologies, Power Levels, Energy Storage Systems, and Standards for Electric Vehicle Charging Stations and Their Impacts on Grid

September 2021
IEEE Access PP(99):1-1

DOI:10.1109/ACCESS.2021.3112189

License
CC BY-NC-ND 4.0

Authors:

Irfan Khan

Texas A&M University

M. S. Jamil Asghar

Aligarh Muslim University

Show all 5 authorsHide

The penetration of electric vehicles (EVs) in the transportation sector is increasing but conventional internal combustion engine (ICE) based vehicles dominates. To accelerate the adoption of EVs and to achieve sustainable transportation, the bottlenecks need to be elevated that mainly include the high cost EVs, range anxiety, lack of EV charging infrastructure, and the pollution of the grid due to EV chargers. The high cost of EVs is due to costly energy storage systems (ESS) with high energy density. This paper provides a comprehensive review of EV technology that mainly includes electric vehicle supply equipment (EVSE), ESS, and EV chargers. A detailed discussion is presented on the state-of-the-art of EV chargers that include on-/off-board chargers. Different topologies are discussed with low-/high-frequency transformers. The different available power levels for charging are discussed. To reduce the range anxiety the EV chargers based on inductive power transfer (IPT) are discussed. The last part of the paper focuses on the negative impact of EV chargers along with the remedies that can be adopted. The international standards decided by different institutions and adopted universally are discussed in the latter part of this paper and finally, this paper concludes with the near to future advancement in EV technology.

Sector-wise C02 emission from fuel combustion [5].

…

Efficiencies of different vehicles.

…

Photograph of a typical charging pool.

…

On-board and Off-board conductive charging infrastructures.

…

Three-level ac-dc front-end converter integrated with dc-dc converter.

…

Figures - available via license: Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International

Content may be subject to copyright.

Available via license: CC BY-NC-ND 4.0

Content may be subject to copyright.

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/

This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication. Citation information: DOI 10.1109/ACCESS.2021.3112189, IEEE Access

VOLUME XX, 2017 1

Date of publication xxxx 00, 0000, date of current version xxxx 00, 0000.

Digital Object Identifier 10.1109/ACCESS.2017.Doi Number

A Comprehensive Review on Structural

Topologies, Power Levels, Energy Storage

Systems, and Standards for Electric Vehicle

Charging Stations and their Impacts on Grid

Mohd Rizwan Khalid1, Member, IEEE, Irfan A. Khan2, Senior Member, IEEE, Salman

Hameed1, Member, IEEE, M. S. Jamil Asghar1, Member, IEEE, Jong-Suk Ro3

1Department of Electrical Engineering, Aligarh Muslim University, Aligarh-202002, INDIA

2Department of Electrical and Computer Engineering, Texas A&M University, Galveston, USA

3School of Electrical and Electronics Engineering, Chung-Ang University, Dongjak-gu, Seoul, 06974, Republic of Korea

3Department of Intelligent Energy and Industry, Chung-Ang University, Dongjak-gu, Seoul, 06974, Republic of Korea

Contact address of corresponding author (Corresponding author) Jong-Suk Ro is with School of Electrical and Electronics Engineering and Department of

Intelligent Energy and Industry, Chung-Ang University, Building 310, Room 633, Dongjak-gu, Seoul, 06974, Republic of Korea (Zip Code: 06974 or 156-

756) (phone: +82-2-820-5557; e-mail: jongsukro@gmail.com)

1. This work was supported by the Human Resources Development (No.20184030202070) of the Korea Institute of Energy Technology Evaluation and

Planning (KETEP) grant funded by the Korea government Ministry of Trade, Industry and Energy.

2. This research was supported by Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of

Education (2016R1D1A1B01008058)

ABSTRACT The penetration of electric vehicles (EVs) in the transportation sector is increasing but

conventional internal combustion engine (ICE) based vehicles dominates. To accelerate the adoption of

EVs and to achieve sustainable transportation, the bottlenecks need to be elevated that mainly include the

high cost EVs, range anxiety, lack of EV charging infrastructure, and the pollution of the grid due to EV

chargers. The high cost of EVs is due to costly energy storage systems (ESS) with high energy density.

This paper provides a comprehensive review of EV technology that mainly includes electric vehicle supply

equipment (EVSE), ESS, and EV chargers. A detailed discussion is presented on the state-of-the-art of EV

chargers that include on-/off-board chargers. Different topologies are discussed with low-/high-frequency

transformers. The different available power levels for charging are discussed. To reduce the range anxiety

the EV chargers based on inductive power transfer (IPT) are discussed. The last part of the paper focuses

on the negative impact of EV chargers along with the remedies that can be adopted. The international

standards decided by different institutions and adopted universally are discussed in the latter part of this

paper and finally, this paper concludes with the near to future advancement in EV technology.

INDEX TERMS Charge depletion, Charge sustaining, electric vehicle, Internal combustion engine, Power

factor, Power quality

I. INTRODUCTION

The economic and social development depends mainly on

the existing transportation sector in the country [1]. At

present, internal combustion engine (ICE) based vehicles

have domination in this sector. The tailpipe emissions and

exhaust from these directly affect the climate and the

pollutants aids in reducing the air quality which has adverse

results on human health and the ecosystem [2], [3]. The

transportation sector is responsible for about 24% of the

total CO2 that results from the combustion of fossil fuel [4].

Figure 1 shows the sector-wise emission of CO2from the

combustion of fuel and is likely to increase with

urbanization, industrialization, and with an increase in the

number of vehicles, in the coming future [5]. To reduce the

aforementioned concerns, there is a need to find an

alternative for the transportation sector.

The inclusion of electric vehicles (EVs) in the transportation

sector is the bright option for reducing tailpipe emissions that

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/

VOLUME XX, 2017 1

can improve the air quality and therefore reduce the adverse

effects of ICE-based vehicles [1]. Moreover, EVs are

comparatively efficient, have better performance, and have a

lower driving cost per mile, as compared to ICE-based

vehicles. The electric motor that drives EVs utilizes 80-85%

of the total energy that is supplied through the batteries

compared to 12-30% that the ICE-based vehicles utilize [6].

Further, the tank-to-wheel efficiency of EVs is higher than

that of the ICE-based vehicle, as shown in Figure 2.

Figure 1: Sector-wise C02 emission from fuel combustion [5].

H2gas

H2liquid

Fuel cell

Power

electronics

converter

Motor Transmission

Battery

Petrol/Diesel

tank

Petrol/Diesel

engine

Gearbox/

Transmission

Internal combustion engine based

vehicle

Electric vehicle

Wheel

100%

98%

50% 95% 80% 92%

80%

99%

100 % 45%

Figure 2: Efficiencies of different vehicles.

On 5th December 2015, 195 countries participated in Paris

Climate Conference and adopted the first ever universally

and legally adopted agreement on climate change [7]. In the

conference, amid growing concerns on climate change were

addressed and the governmental policies to endorse the use

of electricity in the transportation sector were proposed.

Presently, the transportation sector contributes to 24% of

the total CO2 emitted by mankind and this figure is going to

increase at an alarming rate with an increase in urbanization

and industrialization [4].

Shifting from petroleum or fossil fuel-based

transportation to an electricity-based transportation system

has evolved an idea of EVs that are powered through an on-

board energy storage system (ESS) and the latter is being

of supplying the energy demands of the EV. Recent

research and advancements in technology over the last

couple of years have suggested the use of Li-ion batteries in

EVs [8], [9]. Despite improvements in Li-ion batteries, the

energy density is 200 300 Wh/kg which is much low in

comparison to petroleum (13,000 Wh/Kg). Due to this, the

driving range of an EV is limited in one complete charge of

having no charge and also unable to charge at the desired

moment [6].

Another bottleneck in the wide adoption of EVs is the

lack of proper EV charging infrastructure that can replace

and compete with the existing refueling stations [10], [11].

In addition to this, the deployed charging infrastructure

must avoid the deleterious harmonic effects on the electric

utility distribution system [12], [13]. Therefore, the

development of the EV charging infrastructure parallel to

the existing refueling station with minimal impact on the

existing electric utility distribution system is urgently

required particularly in the regions where long driving is

required (highways). Moreover, the developed EV charging

infrastructure must incorporate the industry standards,

available technology along with the government policies

[14].

The EV charging infrastructure is mainly categorized

into two categories, (a) inductive power transfer (IPT) or

wireless power transfer (WPT) and (b) conductive power

transfer. Both have their own merits and demerits over each

other. Further, these are subdivided into on-board and off-

board charging infrastructures [15], [16]. In on-board EV

charging infrastructure the EV charger circuitry is placed

inside the EV along with the ESS, while, in off-board EV

charging infrastructure, the charging circuitry is not an

integral part of the EV.

The main idea of this paper is to develop the off-board

charging infrastructure that can be deployed similar to the

refueling stations and can elevate the bottleneck in the vast

adoption of EVs due to the lack of availability of proper EV

charging infrastructure. Moreover, the developed EV

charging infrastructure is reliable; robust; modular in

nature; cost comparative and satisfies IEEE 519-2014

power quality (PQ) standards.

Further, this paper provides an introduction to different

types of EVs that are available commercially and discusses

the technology for the ESS. The in-depth review on the

electric vehicle supply equipment (EVSE) which includes

mainly EV charging cords, residential and public charging

stands, plugs, power outlets with different recommended

power levels by the society of automotive engineers (SAE)

is presented. In the latter part of this paper, a

comprehensive state-of-the-art review of the available

topologies for the EV charging stations is presented along

with their negative impacts on the electric utility

distribution system. Finally, the technical codes and

standards for safety and isolation conclude this paper.

II. Classification of EVs

Based on the combination of electrical and fuel energy that

drives them EVs are broadly classified into three main

categories [17].

Electricity

and heat

production

43%

Other

energy

industry own

use

Manuf.

industries

and

construction

19% Transport

24% Residential

Commercial

and public

services

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/

VOLUME XX, 2017 1

A. Battery Electric Vehicle (BEV)

A battery electric vehicle (BEV) is based only on an

electric motor and ESS and does not need the support of

traditional ICE. They are plugged into an electrical supply

to recharge their ESS (batteries) when they are exhausted.

BEVs can also recharge their batteries through the

electric motor to assist in slowing down the vehicle and to

recover the energy which is usually converted to heat

energy by the brakes [18].

Some commercially available BEVs are Tesla Model

S, Nissan Leaf, BMW i3, Mitsubishi iMiEV, Smart EV,

Ford Focus EV, etc. The main advantages of BEVs are:

Zero tailpipe emissions.

No need for gas or oil refueling.

Easy to be charged at home.

Fast and smooth acceleration.

Overall low cost of operation.

Apart from the advantages, some disadvantages are:

Shorter drive range as compared to ICE-based vehicles.

Expensive than ICE-based vehicles, however, the

payback period from fuel savings is only about 2-3

years.

B. Plug-in Hybrid Electric Vehicle (PHEV)

The plug-in hybrid electric vehicle (PHEV) uses an electric

motor and ESS along with the ICE. The feature of having

ICE in PHEV makes it a more suitable and promising

option for long-distance journeys. The operation of PHEV

is divided mainly into two modes; namely, charge depleting

(CD) mode and charge sustaining (CS) mode. In CD mode,

PHEV disables its ICE and draws vehicle driving energy

entirely from the battery until it reaches a threshold state-

of-charge (SOC), where SOC is a quantity that measures

the percentage of remaining charge in the battery. Upon

reaching the minimum SOC, PHEVs switch their operation

to CS mode and the IC engine provides energy to drive the

vehicle as well as to maintain battery charge above but near

to the minimum SOC. For better fuel efficiency, a third

mode, called charge blended (CB) mode has been

introduced, in which electric motor and IC engine are

optimally and dynamically employed during a drive cycle

so that they are able to operate longer using the most

efficient settings while achieving an overall reduction in the

emissions [19]. Commonly available PHEVs are BMW i3,

BMW i8, Cadillac ELR, GM Chevy Volt, Porsche SE, Ford

Fusion Energi, Ford Cmax Energi, Toyota Prius Plugin.

The advantages of PHEVs are:

Long driving range.

Low fuel consumption than conventional ICE-based

vehicles.

Low emission of pollutants in the environment.

Some disadvantages of PHEVs are:

Environmental pollution is not eliminated.

Expensive to operate as compared to BEVs.

C. Hybrid Electric Vehicle (HEV)

Hybrid electric vehicles (HEVs) have two driving systems,

ICE with a fuel tank and an electric motor with an ESS.

Both, ICE and the electric motor drive the vehicle at the

same time. However, HEVs do not have the facility of

charging from the utility grid, all their driving energy

comes from the fuel and the regenerative braking process in

the vehicle [20], [21]. Some commonly available HEVs are

Audi Q5 Hybrid, Acura ILX Hybrid, Cadillac Escalade

Hybrid, BMW Active Hybrid 3, BMW Active Hybrid 5,

BMW Active Hybrid 7, Honda Civic Hybrid, Honda CR-Z

Hybrid. Some advantages of HEVs are:

Longer driving range than BEVs.

Lower fuel consumption compared to ICE-based

vehicles.

Lower emissions than ICE-based engines.

Some disadvantages of HEVs are:

Zero tailpipe emission is not achieved.

The mechanism of operation is complex.

Expensive to operate as compared to BEVs.

Cheaper compared to ICE-based vehicles.

Figure 3 shows the architecture of BEVs, PHEVs, and

HEVs that explains the working mechanisms. It is

estimated that energy consumption per mile for all EVs lies

approximately in the range of (0.25 - 0.45) kWh/mile,

Table 1.

Battery Electric Motor

Fuel Tank

Internal

Combustion

Engine

(a)

Battery Electric Motor

(b)

Battery Regenerative

Braking

Fuel

Tank

Internal Combustion

Engine

Electric Motor

(c)

Figure 3: Architecture of (a) PHEVs. (b) BEVs. (c) HEVs.

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/

VOLUME XX, 2017 1

Table 1: EVs energy consumption [15].

III. Energy Storage System (ESS)

To make EVs suitable for long-distance journeys, the ESS

(batteries) in the EVs should meet criteria in terms of high

energy density for extending the driving range of EVs; high

power density for the fast acceleration of EVs; a large

number of life cycles; wide range of temperature in which

they can operate and low maintenance, the capability of

accepting high power repetitive charges from regenerative

braking operation [22].

The rate at which a battery is charged depends directly

on the internal DC resistance (DCR) of each cell, the

chemistry involved in it, and the charging techniques used to

charge the battery. In an ideal battery, the value DCR should

have a low value to achieve high efficiency with low heat

generation. Batteries used in EV applications require more

safety precautions because frequent fast charge/discharge

operations in EV battery leads to the generation of excessive

heat. There are several types of batteries that are

commercially available and currently used in various EVs

[23]. The different types of chemistries involved in the

batteries of EVs are discussed below.

A. Nickel-Metal Hydride (NiMH) Batteries

These batteries have high energy and power densities as

compared to conventional lead-acid batteries. However,

these batteries have poor performances at extremely high and

low temperatures and also require frequent maintenance. As

the EVs require high-capacity batteries with the capability of

many deep discharge cycles, these batteries are not suitable

for EV applications.

B. Nickel-Cadmium (NiCD) Batteries

Nickel-Cadmium (NiCD) batteries are suitable for deep

discharge cycle applications and have better performances at

high temperature operating conditions. However, NiCD

batteries have low energy density and contain an appreciable

amount of toxic metals which limits their use in EV

applications.

C. Lithium-ion (Li-ion) Batteries

Lithium-Ion (Li-ion); Lithium-Ion Polymer and Lithium-Iron

Phosphate batteries have high energy density and due to

which these are lighter in weight in comparison to other

batteries, this makes it most suitable for EVs applications.

Typically, lithium-ion batteries have four major

chemistries based on cathode materials, namely; cobalt,

manganese, nickel-cobalt-manganese, and phosphate

utilizing either carbon or graphite as an anode. Among these,

cobalt oxide which has the highest energy density (Wh/kg) is

found thermally unstable, and its internal resistance varies

considerably with time and depends on the energy output,

resulting in a reduced cycle life [24]. On the other hand,

manganese oxide has low cost, high energy density, and

safety but has limitations in terms of limited operating

temperature and low volumetric energy density [25].

New lithium-ion chemistry is iron-phosphate that

delivers high currents and offers a large number of life cycles

as compared to other available technologies. However, its

energy capacity is lower than other lithium chemistries, but

these batteries are capable of maintaining their nameplate

capacity longer than any other technology due to the low and

stable value of internal DC resistance. Table 2 compares the

performance parameters of different batteries [23].

IV. Charging Techniques of ESS

Charging of ESS depends on the rate of transfer of energy,

for EV owners it is desirable to utilize fast charging

techniques at high power levels to charge the EVs battery in

less time. The chemistry involved in a battery determines the

power level at which it can be charged [37].

Furthermore, the charging methods/techniques adopted are

also responsible for the fast charging of EVs. Several

charging techniques are discussed below:

A. Constant Current-Constant Voltage (CC-CV) Mode

Constant current-constant voltage (CC-CV) mode is the

conventional method of charging. The main idea of this

technique is to charge the EV battery a constant maximum

current (recommended by the manufacturer) up to some

threshold (cut-off) voltage and then the battery is charged at

this threshold voltage, till the battery starts charging at

around C/10 or less of the defined capacity. CC-CV charging

profile of a battery is shown in Figure 4(a) [37].

B. Multistage Constant Current-Constant Voltage (CC-

CV) Mode

Vehicle class Energy consumption per mile

(kWh/mile)

PHEV-30

(kWh)

PHEV-40

(kWh)

Compact sedan 0.26 7.8 10.4

Mid-size sedan 0.30 9.0 12.0

Mid-size SUV 0.38 11.4 15.2

Full-size SUV 0.46 13.8 18.4

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/

Author Name: Preparation of Papers for IEEE Access (February 2017)

2 VOLUME XX, 2017

Table 2: Performance parameters of different EES [25]-[36]

Multistage constant current-constant voltage (MCC-CV)

mode is a modified CC-CV mode that increases the charge

acceptance rate of the battery. The basic principle is the same

as that of CC-CV mode with the exception that in CC-CV

mode only one constant current level is used till the threshold

voltage level, while in MCC-CV mode many current steps

are applied up to the threshold voltage, shown in Figure 4(b).

The above-stated charging methods are traditional and

have limitations in their capability to deliver high power due

to polarization. The new charging methods that reduce the

effect of polarization, and thus increase the charging

acceptance, are still being the active area for the researchers.

Discharging the battery at specific time intervals during

charging is one method to increase charge acceptance [38].

This method is applicable to both CC-CV and MCC-CV

modes in order to yield a superior result. An advanced way

of CC-CV mode with negative pulses is shown in Figure

4(c). Another approach discussed in [39] uses a variable

pulse charge strategy, in which optimal pulse charge

frequency is continuously calculated and optimized in order

to distribute the ions in electrolytes evenly. Between the

pulses, a variable rest period is given that neutralizes and

diffuses the ions. This rest period is predefined by the

maximum power point tracker (MPPT) to determine the

maximum current that can be given for a given SOC in real-

time. Typical characteristics of the variable frequency

associated with pulse charging are shown in Figure 4(d).

Incorporation of this method increases the charge acceptance

as compared to the conventional CC-CV and fixed frequency

pulse charging method.

V. Electric Vehicle Supply Equipment (EVSE)

The electric vehicle supply equipment (EVSE) provides

electric power to recharge the battery of EV. EVSE is

commonly known as EV charging stations or EV charging

points [16]. EVSE includes the electrical power conductors,

related equipment, software, and communications protocols

that deliver the electrical energy efficiently and safely from

the electric utility distribution system to the ESS of the EVs.

Figure 5 shows the block diagram of a charging pool that has

several EV charging stations. A charging pool contains

several charging stations, while a charging station contains

several charging points. Each charging point has several

connectors and per charging point not more than one

connector can be active at a time [40]. A photograph of a

typical charging pool is shown in Figure 6 [16].

ICC

(a)

MCC CV

(b)

Time (s)

(c)

Time (s)

ICC

(d)

Figure 4: Traditional and advanced charg ing techniques.

Charging Pool

Connector

Charging Point

Figure 5: Block diagram of charging pool.

Type Energy Efficiency (%) Energy Density

(Wh/Kg)

Power Density

(W/Kg)

Life Cycles

(cycles)

Self-Discharge

Pb-Acid 70 - 80 20 35 25 200 2000 Low

Ni-Cd 60 90 40 60 140 180 500 2000 Low

Ni-MH 50 80 60 - 80 220 <3000 High

Li-ion 70 85 100 200 360 500 2000 Medium

Li-polymer 70 200 250 - 1000 >1200 Medium

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/

Author Name: Preparation of Papers for IEEE Access (February 2017)

2 VOLUME XX, 2017

Figure 6: Photograph of a typical charging pool.

A. Charging Pool

A charging pool consists of single/multiple charging stations

and the parking bays, shown in Figure 6. The charging pool

is operated by one charge point operator (CPO) and a global

positioning system (GPS) coordinates at a location. The

tools, and the features that represent a charging infrastructure

on a map.

B. Charging Station

A Charging Station is a physical structure having one or

more charging points that share a common user identification

interface (UII). Some charging stations have radio-frequency

identification (RFID) readers, displays, and LEDs, while

displays, etc.

C. Charging Point

The electric energy is delivered to the EV through the

charging point. A charging point has one or many connectors

to accommodate different types of connectors (discussed

latter). As shown in Figure 6, only one connector is used at a

time.

D. Connectors

The connector is a physical interface between EV and its

charging station that provides electricity for the charging

purpose, as shown in Figure 6. Different types of connectors

are discussed and explained in the latter part of this paper.

VI. Classification of EV Chargers

Charging of EV requires either single-phase or three-phase

chargers with unidirectional or bidirectional power flow

capabilities [16], [41]-[43]. EV chargers are classified into

conductive and inductive chargers. Conductive charging

technology is well developed while inductive charging

technology remains the hot topic for researchers.

A. Conductive Charging

Conductive charging involves direct metal-to-metal

contact between the utility grid and the EV to transfer the

power. This method of charging is found to be highly

efficient and robust. Conductive chargers are classified as

on-board and off-board charging infrastructures. On-board

chargers are integrated with the EV, due to constraints on

weight, space, size, and cost power level of these types of

chargers are limited [44]-[45]. On the other hand, off-board

EV chargers have no constraints on their size, weight, and

space since they are not an integral part of EV and are

installed in public parking bays like those of hospitals,

shopping malls, and universities. Figure 7 shows the block

diagram that highlights the difference between on-board and

off-board chargers. On-board chargers are generally used for

slow charging purposes while off-board chargers are

intended for fast charging.

B. Inductive Charging

Inductive or wireless chargers work on the principle of IPT,

i.e. mutual induction to transfer power from the utility grid to

the EV. It requires no physical contact between the utility

grid and EV. Moreover, they may or may not require

isolation transformers for safety purpose, thus it has reduced

size as compared to the conductive chargers [46]. However,

inductive chargers are comparatively less efficient due to

misalignment between the power transferring coils. Inductive

chargers are classified into three categories, a) static

inductive chargers, b) dynamic inductive chargers, and c)

quasi-dynamic inductive chargers [47]-[50], confer Figure 8.

Figure 9 shows the schematic of static and roadbed inductive

chargers for charging EVs wirelessly. Static inductive

chargers have two coils; one is installed in the charger, i.e.

outside the EV while the other coil is an integral part of the

EV. To achieve high efficiency both coils are aligned

properly. Roadbed inductive charging has the ability to

charge the EV when it is in motion. In this charging method,

special charging tracks are laid on the roads (usually

highways) that are capable of charging the EV and reduce

the range anxiety and capacity of ESS. In quasi-dynamic

inductive charging, the EV is charged whenever it stops for a

small interval, like on traffic signals.

Distribution

System

Operator

Protection

Unit

EMI

Filter

Corrector

DC-DC

Converter

Protection

Unit Battery

Pack

BMS Voltage/Curren

Protection

Unit Battery

Pack

BMS

Voltage/Current

DC-DC

Converter

PFC

EMI

Filter

400 VDC

Protection

Unit

EV Charging System

(On-Board Charger) Status/SOC

1-Phase/3-Phase Supply

AC Level-II

Power Flow

Signal Flow

1-Phase/3-Phase Supply

DC Fast Charger Requirements

Off-Board Charger

DC Fast Charger

SOC

Figure 7: On-board and Off-board conductive charging infrastructures.

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/

Author Name: Preparation of Papers for IEEE Access (February 2017)

2 VOLUME XX, 2017

Inductive Chargers

Static Inductive

Chargers

Quasi-Dynamic

Inductive Chargers

Dynamic Inductive

Chargers

Figure 8: Classification of inductive chargers.

Off-Board Infrastructure On-Board Infrastructure

Charge port

(Secondary transducer)

Paddle

(Primary Transducer)

(a)

Pickup

Inductance

Track Inductance

Track Distance

High Frequency AC

Source (20kHz)

Pickup

Compensator

Track

Compensator

(b)

Figure 9: Schematic of (a) stationary inductive charging and (b) roadbed

inductive charging.

C. Unidirectional and Bidirectional Chargers

Between EV and the utility grid, two possible types of power

flow are shown in Figure 10. EVs with unidirectional

chargers charge the EV but do not inject the energy of EV

into the utility grid. These chargers generally have a diode

bridge rectifier (DBR) along with filter and dc-dc converters.

Nowadays these converters are realized as a single-stage that

limits size, weight, cost, and losses [51]. High-frequency

isolation transformers are employed to get the isolation

during charging of EV [57]. Simple control of the

unidirectional chargers makes them an easy option for a

utility to manage a fleet of EVs [42]. Chargers having active

front ends have the ability to provide reactive power support

through the current phase angle control without discharging

the battery. With increased penetration of EVs in the utility

grid and active charging current control, unidirectional

chargers seem to be a promising solution to meet most utility

objectives while avoiding the cost, safety, and performance

concerns that are associated with the bidirectional chargers

[58], [59].

On the other hand, a bidirectional charger has two power

stages; one is an active grid-connected bidirectional ac dc

converter that endorses unity power factor (PF), and the

second is a bidirectional dc-dc converter that regulates the

charging current [52], [57]. These chargers utilize both

isolated and non-isolated circuit configurations. When

charging the EV, they must draw sinusoidal current from the

utility grid with a defined phase angle to control real and

reactive power. While in discharge mode, the charger must

be capable of returning the power to the grid with the

required PF [60], [61].

Figure 11 shows the classification of unidirectional and

bidirectional chargers. Among these single-phase chargers

are used for slow charging purposes while three-phase

chargers are utilized in fast charging of EVs. Isolated

chargers include diode bridge rectifiers (DBR) along with

Flyback/ Forward/ Push-pull/ SEPIC/ CUK/ Multilevel

circuit configurations, while non-isolated chargers include

DBR along with Buck/ Boost/ Buck-Boost circuit

configurations.

Filter

Unidirectional Power Flow

Bidirectional Power Flow

Figure 10: Unidirectional and bidirectional charger topology.

Chargers

Unidirectional

Chargers

Bidirectional

Chargers

Single-phase

Isolated/Non-isolated

Chargers

Three-phase

Isolated/Non-

isolatedChargers

Single-phase

Isolated/Non-

isolatedChargers

Three-phase

Isolated/Non-

isolatedChargers

Figure 11: Classification of inductive chargers.

VII. Charging Power Levels of EV

Charging power levels of EVs reflect power, charging

duration, cost, location, equipment, and its effect on the

utility grid. Deployment of charging infrastructure and EVSE

is a complex aspect due to many issues that need to be

resolved: charging time, demand policies, standardization of

policies for charging stations, and regulatory procedures.

Availability of proper charging infrastructure may reduce on-

board ESS requirements and costs drastically.

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/

Author Name: Preparation of Papers for IEEE Access (February 2017)

2 VOLUME XX, 2017

As mentioned earlier, the charging cord, charging stand

(residential or public), attachment plugs, power outlets, EV

connectors, and protection equipment are major components

of EVSE. These are categorized in two configurations: one

as a specialized cord set, and the other as a wall or pedestal

mounted box. However, the specific configurations vary with

location and country depending on utility supply voltage,

frequency, grid connection, and transmission standards [62].

According to the electric power research institute (EPRI),

most EVs are likely to charge at home during the night. For

this reason, level-1 and level-2 charging seem to be the

primary option. Table 3 summarizes the power levels for EV

charging.

A. Level-1 Charging

Level-1 charging is categorized as slow charging. In the

U.S., level-1 uses a 120 V/15 A standard single-phase

grounded outlet, such as a NEMA 5-15R. The connection

uses a standard J1772 connector into the EV as an ac port,

shown in Figure 12 [64]. For domestic and commercial sites,

no additional infrastructure is required. A cheaper charging

rate is available during off-load periods, likely to be

available at night.

combo connector.

Level-1 charging is generally provided by the on-board

chargers, up to a power level of 1.9kW through 120V single-

phase AC supply. The acceptable charging current range is

15-20Amps. Depending on the ESS type and its capacity,

level-1 charging usually takes about 3-20 hours to fully

recharge the EV. As the standard electrical outlets are

available almost everywhere and the charging time is long,

the level-1 charging is particularly suitable for overnight

charging which usually takes place at homes or in the

parking bays of the large residential buildings. Chargers

supporting this level of charging are usually on-board

chargers.

B. Level-2 Charging

Level-2 charging is the primary method of charging in public

and private facilities. The chargers of this category can be

on-board type to reduce power electronics. Existing level-2

chargers offer charging in the range of 208V or 240V (max

80 A, 19.2 kW). It requires dedicated equipment and

installation for their deployment at the domestic and

commercial level, EVs such as Tesla have the on-board

power electronics and need only the outlet. Most U.S. homes

have a 240V supply available and level-2 chargers charge the

EV battery during the night. EV owners have an interest in

level-2 chargers owing to their short charging time and

standardized charger-to-vehicle connection. Installation cost

of level-2 charger is around $1000 to $3000 [66]. The new

standard has an SAE J1772 [64] ac charge connector on top

and a two-pin dc connector below and is intended to enable

either ac or dc fast charging via a single connection (confer

Figure 12).

C. Level-3 Charging

Level-3 is the future and has the ability to elevate the range

anxiety and ESS of EVs. This offers commercial fast

charging that charges the EV in less than an hour. These

chargers are installed along the highway sides parallel to the

refueling stations. Level-3 chargers are usually off-board

chargers and operate on 480V or higher three-phase supply.

The connection to the vehicle may be direct dc. The dc plug

intended for charging is shown in Figure 12. CHAdeMO, a

Japanese protocol has gained international recognition for

fast charging [67]. Cost of level-3 chargers ranges between

$30,000 to $160,000 [68]. According to the SAE J1772

standard, level-1 and level-2 EVSE must be on-board, while

level-3 EVSE must be off-board (located outside the EV).

Generally, commercial EV charging stations are level-2 or 3

to enable fast charging.

A low-power charger has the added advantage of having

minimum negative impacts on the utility grid during peak

load periods. While, on the other hand, high power (level-3)

chargers increase the demand and acts as an overload on the

local distribution system, mainly during peak load periods.

The various negative impacts of level-2 and 3 chargers are

increased losses in distribution transformers, frequency

deviation, voltage deviation, harmonic distortion, peak

demand, and thermal loading of the distribution and

transmission system, mainly transformers. The degradation

can be reduced significantly by opting for chargers with high

PQ and deploying them with smart charging schemes [69].

The charging characteristics and infrastructure aspects for a

few EVs are summarized in Table 4.

VIII. State-of-the-Art of EV Chargers

This section focuses mainly on the topologies for on-board

and off-board EV chargers. The ac-dc converter at the front-

end is the key component of the EV charger. Various

topologies and control techniques have been developed for

PF correction applications [70]. The single-phase active PF

correction technique is categorized as a single-stage and two-

stage approach. A single-stage approach is suitable for low-

power applications and has a low-frequency ripple in the

output current. In addition, galvanic isolation for safety

reasons is difficult. Thus, a two-stage approach is a proper

choice for the EV chargers. Figure 13 shows the conductive

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/

Author Name: Preparation of Papers for IEEE Access (February 2017)

2 VOLUME XX, 2017

Table 3: Charging power levels [62]

Table 4: Charging Characteristics and infrastructures of PHEVs and EVs

and inductive charging methods. As discussed earlier, the

conductive chargers have a wired connection between the

utility grid and power electronics interface (PEI) for charging

and usually have a PF corrector, ac-dc rectifier followed by a

dc-dc converter to regulate the charging. Contrary to this,

inductive or wireless charging does not use a wired

connection and the different power conversion stages are

magnetically coupled. Depending on the location, EV

chargers are classified as on-board and off-board chargers.

The on-board charger resides on the EV and consists of

mainly two power conversion stages, namely: (a) ac-dc

converter to rectify utility single-/three-phase supply, and (b)

dc-dc converter for regulating charging current. Off-board

chargers fast and high-power chargers that are installed

outside the EV. To reduce the size, weight, cost, and volume

of on-board chargers, researchers have proposed the

integration of chargers with the bidirectional dc-dc converter

of EV that is used in the propelling unit. Thus, in this way

a single-stage converter is used for charging, motoring, and

regenerative braking. Furthermore, integrated on-board EV

chargers taking advantage of the motor windings and

propulsion inverter have been proposed. The on-board and

off-board charger topologies are mainly determined by the

structure of the ac-dc converters and dc-dc converters. In this

section various ac-dc and dc-dc converters presently used are

presented.

Power Level

Type

Charger

Location

Usage Supply Interface Power Level Charging Time Vehicle Technology

Level-1

120 VAC

(U.S.)

230 VAC

(E.U.)

On-Board

1-Phase Domestic Convenience outlet 1.4kW (12 A)

1.9kW (20A)

4-11 hours

11-36 hours

PHEVs (5-15kWh)

EVs (16-50kWh)

Level-2

240 VAC

(U.S.)

400 VAC

(E.U.)

On-Board

1-/3-Phase

Private

and

Public

Dedicated EVSE

4kW (17A)

8kW (32A)

19.2kW (80A)

1-4 hours

2-6 hours

2-3 hours

PHEVs (5-15kWh)

EVs (16-30kWh)

EVs (3-50kWh)

Level-3

(208-600

VAC or

VDC)

Off-Board

3-Phase

Commercial parallel

to refueling stations Dedicated EVSE 50kW

100kW

0.4-1 hours

0.2-0.5 hours EVs (20-50kWh)

Vehicle Name and

Type

Battery

Capacity

Connector Type Level-1 Charging

Level-2 Charging Level-3/ DC fast Charging

Demand Charge

Time

Demand Charge

Time

Demand Charge

Time

Toyota Prius

PHEV

4.4 kWh SAE J1772 1.4 kW

(120V)

3 hours 3.8 kW

(240V)

2.5 hours NA NA

Chevrolet Volt PHEV 16 kWh SAE J1772 0.96-1.4 kW 5-8 hours

3.8 kW 2-3 hours NA NA

Tesla Roadster EV 53 kWh SAE J1772 1.8 kW 30+

hours

9.6-16.8

4-12 hours

NA NA

Nissan Leaf EV 24 kWh SAE J1772 1.8 kW 12-16

hours

3.3 kW 6-8 hours 50+kW 15-30

minutes

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/

Author Name: Preparation of Papers for IEEE Access (February 2017)

2 VOLUME XX, 2017

Grid AC-DC

Conversion Stage

DC-DC

Conversion Stage

Transmission

Starter and

Generator IC Engine

Electric Motor Motor Inverter

Bidirectional DC-

DC Converter ESS/ Battery

Grid AC-DC-AC

Conversion Stage

Resonant Tank Magnetic Coupling Resonant Tank AC-DC Conversion

Stage

Conductive Charging

Inductive Charging

Electric Vehicle

Clutch

Figure 13: Power conversion stages of EV chargers.

A. PF Corrector ac-dc Converter Topologies

The ac-dc converter at the front-end of the EV charger

converts the single-/three-phase utility supply to dc power

and feeds to an intermediate dc link and also works as a PF

corrector. Cost, robustness, PF, efficiency, control

complexity, and total harmonic distortion (THD) in input line

current drawn from the utility supply are the major factors

that decide the selection of ac-dc converter for rectification

and PF correction process. Boost type configurations and

their derived variants are commonly used [71], [72]. The

conventional boost ac-dc converter operating in continuous

conduction mode (CCM) is the simplest ac-dc converter that

has simple control and implementation. However, high

conduction losses are the main limitations of this converter

that is due to the current flowing through three

semiconductor devices. The high-frequency (HF) operation

poses an additional concern of the diode recovery losses.

This requires the use of Schottky or SiC diodes, which

increases the overall cost of the converter.

Symmetrical and asymmetrical bridgeless boost converters

show improved efficiency over the conventional boost type ac-

dc converter due to the reduced conducting power electronics

devices; however, the issue of high diode reverse recovery

losses remains [71]. Interleaving of two boost ac-dc converters

doubles the switching frequency, thus the size of the filter and

magnetic circuit reduces and energy density is improved. To

increase the efficiency and to minimize the reverse recovery

losses the soft switching technique seems to be promising [73].

The other variations of boost type circuit configurations are the

half-bridge and full-bridge boost ac-dc converters. Although

half-bridge configuration has the ability to achieve voltage

doubling, they are comparatively costlier due to the

requirement of higher voltage rating power electronics

devices. On the other hand, the full-bridge boost ac-dc

converter alleviates the issue of capacitor imbalance at the

expense of increased power semiconductor devices, cost, and

control complexity. For higher voltages (more than 400V), the

three-level ac-dc boost converters are preferred.

B. Isolated dc-dc Converter Topologies

The main objective of the dc-dc converter is to adjust the

output of the front-end ac-dc converter and to charge the EV

in desired mode (CC or CV). The most common dc-dc

converter topologies include voltage-fed bridges; current-fed

bridges; appropriate combinations of these; and resonant

converters [74], [75]. The voltage- and current-fed full-

bridge converter (VCFFB) is the widely used circuit

configuration for charging an EV. Usually, zero voltage

switching (ZVS) is achieved at the current-fed converters

side, while zero current switching (ZCS) is achieved for the

voltage-fed converters. Dual active full bridges (DAFBs)

with voltage-fed bridges on both primary and secondary

sides are also widely employed. In DAFB configuration the

active switch count and device stress is reduced in

comparison to VCFFB.

C. Two-Stage On-Board EV Chargers

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/

Author Name: Preparation of Papers for IEEE Access (February 2017)

2 VOLUME XX, 2017

This section focuses on the on-board EV chargers that utilize

the earlier mentioned rectifiers and dc-dc converters. The EV

chargers consist of a current shaping stage that minimizes the

THD in the input line current and achieves the unity PF

followed by an isolated dc-dc converter for regulating the

charging current. Figure 14, shows a 3.3 kW two-stage EV

charger based on an interleaved ac-dc boost PF corrector

followed by an isolated full-bridge dc-dc converter [76],

[77]. The interleaved PF corrector is realized like two

conventional boost converters working in continuous

conduction mode (CCM), with each working at half of the

full power. The interleaved structure has the ability to reduce

the conduction losses, output capacitor ripples, and size of

the filter circuit because devices are paralleled. The dc-dc

converter at the second stage is implemented by using the

full-bridge topology. In this, switches T3 and T4 are turned on

at a fixed duty cycle of 50%, and T1 and T2 are pulse width

modulated (PWM) on the trailing edge.

R1 D

R3 D

B2C

Figure 14: Interleaved boost PF corrector followed by the full-bridge dc-dc

converter.

For the 0.75 turn-ratio of the transformer, 400 V is obtained

at full load. The reported THD in input line current is less

than 5% and a high PF of 0.99 is achieved. The peak

efficiency reported was 93.6% at the switching frequency at

70 kHz in the front-end and 200 kHz in the dc-dc converter.

The weight and volume of the charger are 6.2 kg and 5.5 L,

respectively.

One major drawback of a conventional two-stage

charger is the bulky dc-link capacitor and this needs to be

reduced to increase the power density and to reduce the cost

and the weight of the EV charger. To mitigate this problem a

full-bridge LLC resonant converter with a boost PF corrector

is reported in [78], shown in Figure 15. At the rated power of

3 kW, the efficiency of 93.6% is achieved with a high PF of

0.996.

Figure 16 shows an on-board charger using an HF

resonant converter with a boost converter for regulating the

charging of EV [79]. The experimental results showed an

efficiency of 92.5% at switching frequencies of 90 and 45

kHz for the resonant converter and the boost converter,

respectively.

Another EV charger topology proposed in [80] is shown in

Figure 17. It constitutes a PF corrector boost converter and a

series resonant-loaded full-bridge dc-dc converter. The

experimental result confirms efficiency of 93% with a high

PF of 0.995. From the aforementioned on-board chargers, it

is inferred that size, weight, and volume have a vital role in

their selection.

T1T2

link

T5T6

LbD

Figure 15: Resonant converter followed b y boost PF corrector.

link

Figure 16: Full-bridge LLC resonant converter and synchronous rectifier

followed by boost PF corrector.

pfc

in L

Figure 17: Boost PF corrector followed by a series-loaded resonant

converter.

D. Integrated On-Board EV Chargers

Integrated EV chargers combine the charging stage with the

bidirectional dc-dc converter that is used in EV to interface

the ESS and inverter (confer Figure 13). In this way number

of power electronics components is reduced and in turn, the

size, weight, and cost of the EV charger are reduced.

Integrated on-board EV chargers offer the advantage of

having a single converter with one inductor for all operation

modes, i.e. charging, driving, and braking. With these EV

chargers, it is possible to charge the EV only when it is at

rest. In [81], a single-stage converter is proposed that

integrates the PEI, as illustrated in Figure 18. The proposed

EV charger is a non-isolated buck-boost active rectifier with

a common inductor which is shared with a bidirectional dc-

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/

Author Name: Preparation of Papers for IEEE Access (February 2017)

2 VOLUME XX, 2017

dc converter of the EV. The charger has a wide range of

input voltage and has the ability to assure unity PF while

being operated in a buck mode (bridge-T1-D5) and in a boost

mode (bridge-T2-D6). It steps up (T4-T2-D8-T5) the input

voltage during driving and steps down (T6-D9-D6-T3-D5)

during the regenerative braking.

Vin

D9T6

VHV

Figure 18: Buck-boost diode rectifier integrated with the dc-dc converter.

The drawback of this charger is that the ESS (battery) draws

an oscillating charging current. Moreover, the charger draws

input line current at high THD in absence of an input filter

and therefore reduces the overall efficiency.

To attain low THD in input line current, a solution is

proposed in [82], as shown in Figure 19. It constitutes a

three-level ac-dc converter at the front-end interfaced with a

dc-dc converter. It draws input line current at a low THD of

2.99% at an expense of a high number of power electronic

active switches. Another solution proposed in [83] is shown

in Figure 20, it constitutes a direct ac-dc converter with

bidirectional switches. It has the ability to inject power back

to the grid in addition to driving, braking, and charging the

EV with a common transfer inductor in all the modes. In

comparison to the charger proposed in [82], it has higher

complexity at an expense of V2G mode.

Figure 19: Three-level ac-dc front-end converter integrated with dc-dc

converter.

Figure 20: Buck/boost bridgeless bidirectional ac-dc converter integrated

with dc-dc converter.

Figure 21 shows an EV charger proposed in [84] with a

reduced number of active/passive components. The THD in

the input line current obtained is low due to the line filters.

An EV integrated charger discussed in [85] utilizes the

-ac converter for charging. In this

EV charger, the existing components of the drivetrain are

reconfigured with minimum additional components to enable

the charging. The PEI of the drivetrain is designed for high

power ratings, thus these chargers have the flexibility of

charging the EV from both single-/three-phase supplies.

These chargers also offer the advantage of reduced weight

and volume as the need for additional elements is elevated.

In [86], two solutions for integrating the drivetrain

components for EV charging are proposed. The first solution,

as shown in Figure 22 utilizes the motor inverter as an EV

charger and an additional diode rectifier with an inductor.

The motor windings in this EV charger are star-connected.

The second solution is shown in Figure 23, which utilizes

motor inverter and delta-wound motor windings, along with

an additional diode bridge rectifier for EV charging. The

advantages of these configurations include component

reduction, and no need for relay circuits for transition

between EV charging and propulsion.

Vin

VHV

Figure 21: Buck-boost bridgeless direct ac/dc bidirectional converter

integrated with dc/dc converter.

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/

Author Name: Preparation of Papers for IEEE Access (February 2017)

2 VOLUME XX, 2017

T1T3

T4T6

EMI

Filter Vin

Motor

Windings

C1L1

Figure 22: Integrated EV charger utilizing motor inverter and star-

connected windings with an additional diode bridge rectifier.

T1T3

T4T6

EMI

Filter Vin

Motor

Windings

Figure 23: Integrated EV charger utilizing motor inverter and delta

connected motor windings with an additional diode bridge rectifier.

T1T3

T4T6

Vin

Motor

Windings

T11

T10 T12

EMI

Filter

Figure 24: Integrated EV charger accessing neutral points of motor

windings in a two-wheel drive.

In [87], another solution based on the combination of

motor driver/charger is proposed, as shown in Figure 24.

This EV charger is for single-phase charging, where the ac

supply is connected to the two neutral points of the motor

windings (one neutral for each winding). In comparison to

the earlier proposed solutions, this EV charger eliminates the

requirement of a diode bridge rectifier and draws input line

current at low THD. Another solution reported in [88] for

single-phase EV charging is shown in Figure 25. The charger

constitutes three contactors to select the mode of operation.

For driving, contactor K3 is closed and K1, K2 is open, while

during EV charging states of the contactors are reversed.

During EV charging (K2 and K1 closed) the leakage

inductances of the motor windings act as inductors for the

boost converter and two legs of an inverter (T1 and T2 and T3

and T4) are controlled by pulse width modulation (PWM).

The input line current is drawn at high PF with low THD.

T1T3

T4T6

EMI

Filter Vin

Motor

Windings

Contractors

Figure 25: Integrated EV charger with motor windings and inverter

working as a single-phase boost ac-dc converter.

T1T3

T4T6

Vin

Motor-1 Motor-2

Switch

Motor-3

Motor-4

Figure 26: Integrated EV charger accessing the neutral points of motor

windings in a four-wheel drive.

T1T3

T4T6Vin

Motor

Windings

LA,B,C

Figure 27: Integrated EV charger incorporating motor windings as three -

phase boost dc-dc converter.

In [89], a four-wheel drivetrain is proposed for EV

charging. Here, every wheel of EV is controlled directly by

an individual three-phase inverter. In this study, the neutral

point of the windings in all four motors is accessed and the

ac input source is connected to the neutral points of two of

these motors. By, incorporating an external selector switch,

the neutral points of the remaining two motor windings are

connected to the battery during EV charging, as shown in

Figure 26. Another integrated EV charger is proposed in

[90], here the diode bridge rectifier and line filters are

connected to the neutral point of motor winding via a

mechanical switch, shown in Figure 27. After rectification,

the three-phase inverter and the motor windings act as an

interleaved boost converter. Since all the motor windings are

utilized together, the current stress at the active switches is

low.

Since accessing the midpoints of motor windings is a

tedious task and requires a specially designed electric

machine, the aforementioned solutions still require reliability

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/

Author Name: Preparation of Papers for IEEE Access (February 2017)

2 VOLUME XX, 2017

enhancements and tests before their widespread adoption and

deployment.

Step-Down

Low Frequency

Transformer

ac-dc

Conversion

Stage

dc-dc

Conversion

Stage

ESS

(EV Battery)

ac-dc

Conversion

Stage

dc-dc

Conversion

Stage

ESS

(EV Battery)

Low Voltage ac Grid

Three-Phase Utility Grid

(a)

Step-Down

Low Frequency

Transformer

ac-dc

Conversion

Stage

dc-dc

Conversion

Stage

ESS

(EV Battery)

Low Voltage ac Grid

Three-Phase Utility Grid

dc-dc

Conversion

Stage

ESS

(EV Battery)

Common dc Bus

(b)

Figure 28: Off-board EV charger configurations with common (a) ac link,

and (b) dc link.

E. Off-Board EV Chargers

For fast high power EV charging, on-board EV chargers are

not feasible due to their increased component cost, size,

weight, and volume. As an alternative solution for fast

charging, the chargers are located outside the EV and are not

an integral part of an EV. In off-board charging stations, each

charging unit shares either a common ac link or a common

dc link, shown in Figure 28. The size of off-board EV

chargers is reduced by incorporating high-frequency

transformers instead of low-frequency transformers that are

bulky, shown in Figure 29. The high-frequency transformer

is utilized as a solid-state transformer (SST) for the dc-dc

conversion stage of the EV charger.

Tesla EV charger is based on this configuration and

constitutes 12 paralleled modules [91]. Table 5 summarizes

specifications of various commercially available EV chargers

based on the aforementioned configuration [14], [91].

The standardized protocols have been developed for off-

board EV chargers by the governing bodies that are

summarized in Table 6. The IEC 62196-3 standard [92]

defines four EV coupler configurations for charging; (a)

configuration-AA, which is proposed and implemented by

CHAdeMO association; (b) configuration-BB, commonly

known as GB/T and used in China only; (c) configuration-

EE, Type-1 combined charging system (CCS) used by North

America; and (d) configuration FF, Type-2 CCS adopted by

Europe and Australia. There is a patented configuration

developed by Tesla and is used exclusively for Tesla EVs.

The ratings of charger and cables decide the limits on the

power to be delivered to the EV in addition to the charge

acceptance ability of ESS. Currently, CHAdeMO supports

the highest power capacity, confer Table 6. For fast charging,

cables with large diameters are needed to avoid overloading

and heating, the approximate weight of the charging cable is

9 kg for a 50 kW charger [93]. In [94], a solution is proposed

to reduce the size and weight of the charger cable without

affecting the power level. Authors have suggested increasing

the voltage limit at which the power is transferred, it reduces

the charging current, and correspondingly the diameter, size,

and weight are also reduced. Cable liquid cooling is another

solution that effectively reduces the thermal stress of the EV

charging cable and thus the target of low weight cable is

achieved. The off-board EV charging stations are categorized

as the ac-connected chargers and dc-connected chargers

based on the common ac link and dc link, respectively,

shown in Figure 28. The ac-connected chargers have a step

low-frequency transformer between the utility and a common

three-phase ac link operating at 250 480 V line-to-line RMS

voltage. The common ac link powers each charger at the

station, and each charger has a separate ac-dc power

conversion stage for controlled charging. This approach

increases the power conversion stages between the utility and

the dc link.

ac-dc

Conversion Stage

Three-Phase Utility Grid

dc-ac

Conversion stage

High-Frequency

Transformer

ac-dc

Conversion Stage EV Batter

Isolated dc-dc Converter

Figure 29: Off-board EV charger with solid-state transformer.

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/

Author Name: Preparation of Papers for IEEE Access (February 2017)

2 VOLUME XX, 2017

Table 5: Specifications of off-board EV chargers

Table 6: Standards for off-board dc-fast EV chargers

Standard CHAdeMO

IEEE 2030.1.1

IEC 62196-3

(Configuration AA)

GB/T

GB/T 20234.3

IEC 2196-3

(Configuration BB)

CCS Type 1

SAE J1772

IEC 62196-3

(Configuration EE)

CCS Type 2

IEC 62196-3

(Configuration FF)

Tesla

Coupler

Inlet

Maximum

Voltage

1000 V 1000 V 600 V 1000 V 410 V

Maximum

Current

400 A 250 A 200 A 200 A 330 A

Available

Power

400 kW 120 kW 150 kW 175 kW 135 kW

Manufacturer ABB Tritium PHIHONG TESLA EVTEC ABB

Model Tera 53 Veefil-RT Integrated Type Supercharger espresso&charge Terra HP

Power 50 kW 50 kW 120 kW 135 kW 150 kW 350 kW

Supported

Protocols

CCS Type-1

CHAdeMO- 1.0

CCS Type 1&2

CHAdeMO- 1.0

GB/T Supercharger SAE Combo-1

CHAdeMO 1.0

SAE Combo-1

CHAdeMO 1.2

Input Voltage 480 Vac 380-480 Vac

600-900 Vac

380 Vac ± 15%

480 Vac ± 15%

380-480 Vac 400 Vac ± 10% 400 Vac ± 10%

Output Voltage 200-500 V

50-500 V

200-500 V

50-500 V

200-750 V 50-410 V 170-500 V 150-920 V

Output Current 120 A 125 A 240 A 330 A 300 A 375 A

Volume/Power

(L/kW)

15.16 9.90 4.92 7.75 10.54 5.41

Weight/Power

(K/kW)

8.0 3.3 2.0 4.44 2.66 3.82

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/

Author Name: Preparation of Papers for IEEE Access (February 2017)

2 VOLUME XX, 2017

Moreover, the overall complexity and the cost of the charger

are increased due to the higher number of power conversion

stages. The advantages of adopting the ac link base EV

charging station include the availability and maturity in the ac-

dc and dc-ac power conversion technology, availability of the

ac protective devices, and switchgear [95]-[98]. For the dc-

connected chargers, a central front-end ac-dc converter

rectifies grid power and feds to dc link (confer Figure 28). Due

to the presence of a common dc link, distributed energy

resources (DER) and renewable energy resources (RES) can

be interfaced easily in an efficient way. The central front-end

constitutes a low-frequency transformer followed by an ac-dc

conversion stage or an SST (confer Figure 28). The voltage at

the dc link is 1000 V to accommodate the wide EV battery

range (400-800 V). Each charger is interfaced between the dc

link and a dc-dc converter for EV charging and the need for an

individual ac-dc converter is elevated. Compared to ac-

connected chargers, dc-connected chargers have higher

efficiency due to the reduced number of power conversion

stages. The advantages of the dc-connected charger include

load diversification resulting from varying EV battery

capacities; the absence of reactive power in the dc systems,

and the opportunity of utilizing partial power converters to

interface dc link and the [99] [102]. The partial power

converters process only a portion of power that is delivered to

EV and thus cost and ratings of the converter are reduced

while efficiency is increased. Despite the aforementioned

advantages, the hurdles in the dc-connected chargers are the

undeveloped technology of adequate dc protection and

metering system [103]. Also, there is a lack of established

standards for protection in the dc-connected chargers due to

complex grounding configuration, fault type, component

specification, system topology [104]. For bidirectional

chargers, this issue is more pronounced because they are more

sensitive to disturbances and becomes unstable in absence of

fast fault clearance. In [105], [106], protection strategies are

presented base on coordination between different protective

devices and loop-type, respectively. The commonly used ac-dc

converters at the front-end are shown in Figure 30 and their

specifications are summarized in Table 7. These converters are

unidirectional or bidirectional in nature and incorporate input

line filters for power conditioning [107]-[112].

LCL Input Filter

ac-dc Conversion St age

(a)

LCL Input Filter

ac-dc ConversionStage

(b)

LCL Input Filter

ac-dc Conversion Stage

(c)

LC Input Filter

ac-dc Conversion Stage

(d)

Figure 30: Configurations of ac-dc front-end converters (a) three-phase

PWM rectifier, (b) neutral point clamp rectifier, (c) vienna rectifier, and (d)

three-phase buck.

The dc-dc converters at the latter stage may be isolated or

non-isolated, depending on the presence of a low-frequency

transformer in the front-stage. If isolation is not provided at

the front-end then non-isolated dc-dc converters are utilized,

else the isolated dc-dc converters with a high-frequency

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/

Author Name: Preparation of Papers for IEEE Access (February 2017)

2 VOLUME XX, 2017

Table 7: Comparison of front-end ac-dc converters

transformer are utilized. Figure 31 and Figure 32, show non-

isolated and isolated converters, respectively, for controlled

charging of EV and their comparison are summarized in

Table 8 [113]-[151].

(a)

(b)

(c)

(d)

(e)

Figure 31: Nonisolated dc-dc converters (a) boost converter, (b)

interleaved boost converter (c) three-level boost converter (unidirectional)

(d) three-level boost converter (bidire ctional), and (e) three-level flying

capacitor converter.

Converter configuration Switches THD (%) PF Range

Active Passive

Three-phase PWM converter 6 0 Low Wide

NPC Convereter 12 6 < 1 Wide

Vienna Converter 6 6 <1 Limited

Three-phae buck converter 6 6 Low Limited

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/

Author Name: Preparation of Papers for IEEE Access (February 2017)

2 VOLUME XX, 2017

(a)

(b)

(c)

(d)

Figure 32: Isolated dc-dc converters (a) phase shift full-bridge converter, (b) LLC

converter, (c) dual active bridge converter, and (d) CLLC converter.

IX. Impact of EV chargers on Utility

The increased deployment of EV chargers increases the load

on utility. For poorly maintained utility, this issue is more

pronounced. This section explores the impact of EV chargers

on various parts of the utility grid and the initiatives are

discussed to reduce them.

A. Impact of RES

Incorporating RES in the utility grid is one of the challenges

due to their intermittency. The evolution of power

electronics-based converters and high-density ESS have

elevated the issues of intermittency and hurdles in interfacing

the EV chargers. A solution to reduce the dispatchability of

wind energy resources is discussed in [152]. The idea is to

control the supply and demand balance of utility during EV

charging and discharging. A study in [153] suggested

maintaining constant power at the feeder that feeds EV

chargers and RES. In [154], an islanded grid operation is

discussed for EV charging and a case study confirmed its

effectiveness with the integration of RES. Study in [155]-

[157] has successfully shown the incorporation of solar

energy for EV charging. A detailed analysis is also presented

to demonstrate the design of solar based EV charging station.

The aforementioned studies show that the incorporation of

RES in the utility grid enhances the grid in terms of power

quality without any negative impact on it.

B. Impact on Grid Stability

The EV load on the grid may raise the problems of stability

in grid utility. Many distribution systems work on the verge

of instability even without the EV load, thus stability analysis

is a must before connecting EV chargers as load. Stability

analysis on IEEE 3-bus test system is performed for

determining the stability of the grid, with and without the EV

charger load [158]. The study confirmed that the EV charger

load reduces the stability of the grid. In another study, the

EV chargers were modeled as a constant power and a

constant impedance load for the stability analysis and the

results show that the constant power model of the EV charger

lowers the grid stability [159], [160]. The incorporation of

EV chargers in V2G mode enhances the grid stability and

even the owners of EVs are able to earn during peak load

periods on the grid [161]-[163].

C. Impact on Supply-Demand Balance of Grid

A study in the city of Australia was carried out to evaluate

the effect of uncontrolled EV charging. For this, all EVs in

the city were considered and results from the study proved

that uncontrolled EV charging increases the load on the grid

and this can lead to total blackout if uncontrolled charging is

carried out during peak load periods [164], [165]. Thus, the

idea of coordinated charging was proposed to avoid

blackouts during peak load periods on the grid. Another

study performed in the city of the United Kingdom showed

that increased penetration of EV charging load by 10%

caused an 18% hike in the demand from utility grid [166],

[167]. To meet the supply-demand balance it is necessary to

integrate the RES in the charging station and utilize the smart

charging techniques that include coordinated charging [168]-

[172].

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/

Author Name: Preparation of Papers for IEEE Access (February 2017)

2 VOLUME XX, 2017

Table 8: Comparison of dc-dc converters

D. Impact on Grid Assets

The main grid components that are affected by EV load,

include transformers, transmission lines, and switchgear

protective devices. These components deteriorate their life

due to thermal overloading [173], [174]. A study in [175]

based on EV chargers installed in the parking area, showed

that there is a need to install new transformers to cope with

the required power demand without exceeding the thermal

limit and reducing the life of transformers. Another study

performed in [176] with different levels of EV penetration

shows the trend of system overloading. This study helps

decide the EV charger locations and further modifications in

the utility system. The study performed in [177] shows that

the Ontario grid is adequate to absorb the EV load

penetration till the end of 2025 without any modifications.

EV load penetration significantly reduces the performance of

the transformer and when a fleet of EVs is charged at night

then the oil-cooled transformers are highly affected and

degraded since transformers are loaded more than their

specified average load [178], [179]. In [180] a study

performed shows that excessive overloading due to EV

charger load leads to insulation failure in the transformer,

however, a controlled EV charging may even derate it [181].

Thus, there is a need for reinforcement in the present grid

structure and research is required to incorporate the smart

charging with the V2G facility such that the negative impact

of charging on grid assets may be reduced or elevated [182]-

[183].

E. Impact on Grid Voltage

This section deals with how the grid voltage is affected as the

penetration of EV chargers is increased. A study performed

in [184] shows 12.7%-43.3% voltage deviation as the

penetration of EV chargers is increased from 20% to 80%.

Penetration of single-phase EV chargers also leads to poor

PF and unbalancing in the grid. 1%-2% penetration of EV

chargers shows the voltage sag [185]. In [186], a study is

performed with 50% to 100% penetration of EV chargers and

the results show that even a level-1 charging is capable to

cause voltage deviations from the normal specified values.

Thus, the EV charger penetration limits must be decided

beforehand and these must be followed to avoid voltage

problems.

F. Impact on Grid Current Harmonics

The non-linear power electronics involved in the EV

chargers are responsible for injecting the current harmonics

into the grid. The amount of THD in the line current drawn

by the EV charger depends directly on the circuit topology of

the charger [187]. Usually, odd harmonics dominate and

contribute to THD in the input line current. Usually, EV

chargers have input line filters before the front-end rectifier

to smooth out the input current so that the harmonics injected

in current are reduced [188]. To reduce the current

harmonics, EV chargers involve high-frequency PWM or

modified PWM techniques, also matrix converters are

involved for multi-phase EV chargers. These high-frequency

converters reduce THD in current but increase the charger

circuit complexity [189], [190]. Active power conditioning

circuits along with the active filters are used for harmonic

reduction. The increased harmonics content in input line

current directly affects the PF which in turn increases the

RMS value of line current and deteriorates the different

assets of the grid (transformer). Thus, the modern EV

chargers deployed at the charging station draw current with

low THD and high PF [191]-[192].

Non-Isolated

Converter

Switches

Advantages Disadvantages

Active Passive

Boost converter 2 0 Simple control Limited voltage & current capability

Interleaved boost converter 6 0 Simple control, modular, high

voltage, and current capability

Limited voltage capability

Three-level boost converter 4 0 Small charging current ripples Non-modular

Flying capacitor converter 4 0 Modular &

Stable operation

Limited protection

Isolated

Phasde shifted full-bridge 4 4 Simple control, Low efficiency

LLC converter 4 4 Soft switching, high PF Low efficiency, complex control

Dual active bridge converter 8 0 Wide output voltage range Soft switching not possible, low

efficiency

CLLC converter 8 0 High PF Complex control

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/

Author Name: Preparation of Papers for IEEE Access (February 2017)

2 VOLUME XX, 2017

G. Impact on Grid Losses

The losses in the grid due to EV chargers are because of

increased RMS current which in turn increases the I2R losses,

where I is the RMS value of current drawn and R is the

equivalent resistance of the grid [165]-[167]. The increased

losses in the grid are also responsible for deteriorating the

life span of grid components. These losses are increased by

40% during the off-peak charging period, while 62% during

the peak period. To reduce these losses the EV charger must

draw the input line current with lower harmonic content and

at a high power factor.

H. Initiatives to Reduce Grid Impact

To reduce the negative impact of EV chargers, various

measures are proposed and are discussed in the literature.

The EV chargers do not overload the grid if it is connected in

a well-planned coordinated way [193]. The losses in the grid

can be minimized by incorporating the smart metering

system to maintain the supply and demand balance [194],

[195]. For reduction of current harmonics in the line current

drawn by the EV chargers, the proposed methods include the

deployment of EV chargers with input line filters for power

conditioning, adopting advanced PWM techniques for

reducing lower order harmonics, and avoiding common

mode current to reduce electromagnetic interference (EMI)

[195]. Usage of RES also reduces the negative impacts of EV

chargers on the grid.

X. International Standards for EV Chargers

The international standards are developed by a team of

experts and are adopted universally. For deployment of EV

chargers successfully various international standards are

developed and published. These are well developed to fulfill

the safety issues, reliability, and interoperability issues of the

EV industry [196]. Various industries that utilize these

standards include EV manufacturers, ESS manufacturers,

utility companies, EV charger manufacturers, code officials,

EV charger safety equipment manufacturers, and insurance

companies.

Different EV charging standards [196]-[204] in the

literature that is utilized are discussed as follows-

A. Society For Automobile Engineers (SAE)

J1772: EV conductive connector/charging method.

J2894: Issues of power quality.

J2836/2847/2931: Communication purposes.

J1773: Inductive coupled charging.

J2293: For energy transfer systems to find the

requirements for EVs.

B. National Fire Protection Association (NFPA)

NFPA 70: Safety management.

NEC 625/626: Charging systems for EVs.

NFPA 70E: For safety.

NFPA 70B: Maintenance of electrical equipment.

C. Institute of Electrical and Electronics Engineers

(IEEE)

IEEE 2030.1.1: Quick DC charging for EVs.

IEEE P2690: Charging network management,

Vehicle authorization.

IEEE P1809: Electric transportation guide.

IEEE 1547: Interconnecting electric system with

distributed resources/Tie Grid.

IEEE 1901: Provide data rate while vehicles are

charged overnight.

IEEE P2030: Interoperability of smart grid.

IEEE 519-2014: Power quality standards.

D. International Electromechanical Commission (IEC)

IEC-1000-3-6: Issues of power quality.

IEC TC 69: Regarding infrastructure of charging

and safety requirements.

IEC TC 64: Electrical installation, electric shock

protection.

IEC TC 21: Regarding battery management.

E. Underwriters Laboratories (UL) Inc.

UL 2231: Safety Purposes.

UL 2594/2251,2201: EVSE.

F. International Organization for Standardization

ISO 6469-1:2009: Used for on-board rechargeable

energy storage systems.

ISO/CD 6469-3.3: Safety specifications.

G. Japan Electric Vehicle Association

JEVS C601: EVs charging plugs.

JEVS D701: Batteries.

JEVS G101-109: Fast Charging.

H. Isolation and Technical Safety Standards

SAE J-2929: This standard is related to the safety of

the propulsion battery system.

SAE J-2910: This standard deals with the electrical

safety of buses and test for hybrid electric trucks.

SAE J-2344: Defines rules for EV's safety.

SAE J-2464: Standard defines the safety rules for

recharge energy storage systems (RESS).

ISO 6469-1:2009 (IEC): Standard is related to

electrically road vehicles, on-board RESS, inside

and outside protection of a person.

ISO 6469-2:2009 (IEC): Safe operation of EVs,

protect against inside failure.

ISO 6469-2:2001 (IEC): Electrical hazard

protection.

IEC TC 69/64: EVs infrastructure safety, electrical

installation, electric shock protection.

NFPA 70/70 E: Standards related to workplace

safety, charging system safety, branch circuit

protection.

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/

Author Name: Preparation of Papers for IEEE Access (February 2017)

2 VOLUME XX, 2017

UL 2202: Standard is related to the protection of the

charging system.

UL 2231: This standard deals with the protection of

the supply circuits.

UL 225a: It provides rules of protection regarding

couplers, plugs, and receptacles.

DIN V VDE 0510-11: Provides safety regulations

for battery installation and secondary batteries.

XI. Near to Future Advancements in EV Technology

Since EVs are supposed to take the place of conventional

vehicles, the development in technology is growing every

day. At present, there are lots of EV charger manufacturers

and these are being even deployed in most of the developed

and developing countries. However, research is going on

towards further improvement and currently, researchers are

more focused towards:

1) Development of robust and cost-effective off-board and

on-board EV chargers with improved power quality at

grid and EV side.

2) Development of high-voltage (1100 V DC) off-board

chargers to reduce the overall footprint of the charging

station.

3) Development of on-board charger with the minimum

requirement of additional PEI.

4) New and optimized design of power pads for efficient

WPT.

5) Optimized planning of EV charging such that the grid

stability is improved and the EV owner can earn by

selling its extra energy either to utility (V2G operation)

or to other EV owners (V2V operation).

6) Usage of wide band-gap power semiconductor devices

such as silicon carbide (SiC) and gallium nitride (GaN).

Key features of these devices are high efficiency, high

power density, and low thermal stress.

7) Development of ESS with high energy density, low cost,

volume, and weight.

XII. Conclusion

This paper describes the need for EVs in the transportation

sector and provides a comprehensive review of different

components of EV technology. EVSE is mentioned along

with the different ESS for EVs. The detailed classification of

EVs is mentioned that include BEVs, PHEVs, and BEVs.

Different on-board and off-board chargers are discussed with

low-/high-frequency transformers in the front-stage and end-

stage, respectively. It is shown that the on-board chargers are

integrated with EVs and are usually low power chargers that

take a long time to fully charge the EVs. While off-board

chargers are high-power chargers that are deployed outside

the EVs and take less than an hour to charge the EV. The

different charging standards, CHAdeMO, GB/T, and CCS

are discussed along with their specifications and connectors.

The concept of IPT for charging the EV while moving is

explained. Furthermore, the negative impacts of EV chargers

on the grid are mentioned along with the remedial solutions.

Different international standards for EV technology are

mentioned that need to be followed universally for the

successful penetration of EVs in the transportation sector.

Finally, the future trends and research areas have been

highlighted that need to be worked on.

References

[1] Mohd Rizwan Khalid, Mohammad Saad Alam, Adil Sarwar,

vehicles charging infrastructures and their impacts on power-

eTransportation, vol.1, 2019.

[2] U.S. Energy Information Administr

Outlook, vol. 0383,

March, pp. 221, 2009.

[3] E-Mobility Options for ADB Developing Member Countries,

ADB Sustainable Development Working Paper Series

pp.1-10, 2019.

[4] Global EV Outlook 20 pp.8-

25, 2020.

[5] IEA, Transport sector CO2 emissions by mode in the Sustainable

Development Scenario, 2000-2030, IEA, Paris, 2020 [Online].

Available: https://www.iea.org/data-and-

statistics/charts/transport-sector-co2-emissions-by-mode-in-the-

sustainable-development-scenario-2000-2030. [Accessed: 30-

May-2021].

[6] M. Ehsani, Y. Gao, and A. Emadi, Modern Electric, Hybrid

Electric, and Fuel Cell Vehicles, 2nd ed. CRC Press, 2010.

[7] Adoption of the Paris Agreement, United Nations, New York,

NY, USA, Dec. 2015.

[8] B. Nykvist

Nature Climate Change, vol. 5, no.

4, p. 329, 2015.

[9]

Nature Energy, vol. 3, no. 4, p. 279, 2018.

[10] S. Ahmed et al. A battery technology

J. Power Sources, vol. 367, pp. 250 262, Nov.

2017.

[11] M. Keyser et al. battery thermal

J. Power Sources, vol. 367, pp. 228 236, Nov.

2017.

[12] J. Beretta, Automotive Electricity. New York: Wiley, 2010.

[13]

IEEE Trans. Ind. Electron., vol. 44, no. 1,

pp. 3 13, Feb. 1997.

[14] H. Tu, H. Feng, S. Srdic and S. Lukic, "Extreme Fast Charging of

Electric Vehicles: A Technology Overview," in IEEE

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/

Author Name: Preparation of Papers for IEEE Access (February 2017)

2 VOLUME XX, 2017

Transactions on Transportation Electrification, vol. 5, no. 4, pp.

861-878, Dec. 2019, doi: 10.1109/TTE.2019.2958709.

[15] M. Yilmaz and P. T. Krein, "Review of Battery Charger

Topologies, Charging Power Levels, and Infrastructure for Plug-

In Electric and Hybrid Vehicles," in IEEE Transactions on

Power Electronics, vol. 28, no. 5, pp. 2151-2169, May 2013, doi:

10.1109/TPEL.2012.2212917.

[16] Netherlands Enterprise

pp.4-10, Jan. 2019.

[17] Vehicle Technologies Program, U.S. Dept. Energy, Washington,

DC, USA, Oct. 2011.

[18] M. Ehsani, Y. Gao, S. E. Gay, and A. Emadi, Modern Electric,

Hybrid Electric, and Fuel Cell Vehicles. Boca Raton, FL: CRC

Press, 2005.

[19] A. Emadi,M. Ehsani, and J.M.Miller, Vehicular Electric Power

Systems: Land, Sea, Air, and Space Vehicles. New York: Marcel

Dekker, 2003.

[20] J. Larminie and J. Lowry, Electric Vehicle Technology

Explained. New York: Wiley, 2003.

[21] ne million plug-in

Proc. IEEE Intell.

Trans. Syst. Conf., Oct. 2009, pp. 141 147.

[22]

of high quality power converters for level 3 off-

in Proc. IEEE Veh. Power Propulsion Conf. , Sep. 2011, pp. 1

10.

[23] S. Vazquez, S. M. Lukic, E. Galvan, L. G. Franquelo and J. M.

IEEE Trans. Ind. Electron., vol. 57, no.12, pp.

3881 3895, Dec. 2010.

[24] -

Proc. WESCON/94, Sept. 27-29, 1994, pp. 242-248

[25]

lithium- Proc.

Battery Conference on Applications and Advances1997, Jan. 14-

17, 1997, pp. 121-125.

[26] GAIA datasheet.

[27] -ion Batteries of

presented

in 2009 ZEV Symposium, Sept. 22, 2009.

[28] Kokam Co., Ltd., datasheet.

[29] A123 Systems, datasheet.

[30] Altairnano, datasheet.

[31] EIG Battery, datasheet.

[32] Thunder Sky/Winston Battery, datasheet.

[33] BYD, datasheet.

[34] RFE, datasheet.

[35] Lishen, datasheet.

[36] -

IEEE Spectrum, April 2010.

[37] -Ion Battery Charger With

Smooth Control Circuit and Built-In Resistance Compensator for

Achieving Stable and Fast Charging IEEE Trans. Circuits and

Systems I: Regular Papers, vol. 57, no. 2, pp. 506-517, 2010.

[38]

Charge Method for Lead- in

, May 2009, pp. 1-5.

[39] L. Chen, R

Variable Frequency Pulse Charge Strategy for Li- in

, June 20-23, 2005, vol. 3, pp. 995-1000.

[40] IEEE Electrification Magazine, vol.9, no.2, June 2021.

[41] B. Singh, B. N. Singh, A. Chandra, K. Al-Haddad, A. Pandey,

-phase improved power

quality ac IEEE Trans. Ind. Electron., vol. 51,

no. 3, pp. 641 660, Jun. 2004.

[42] -to-grid benefits

with unidirectional electric and plug-

in Proc. IEEE Veh. Power and Propulsion Conf., Sep. 2011, pp.

16.

[43] K. Drobnic et al., "An Output Ripple-Free Fast Charger for

Electric Vehicles Based on Grid-Tied Modular Three-Phase

Interleaved Converters," in IEEE Transactions on Industry

Applications, vol. 55, no. 6, pp. 6102-6114, Nov.-Dec. 2019, doi:

10.1109/TIA.2019.2934082.

[44] -board charger for plug-in hybrid

Proc. Power electronics, machine and drives;

pp.1-6, 2010..

[45]

Proc. Int. conf. Electrical

Machines, pp.1-6, 2010.

[46] Esteban Bryan, Maher Sid-

study of power supply architectures in wireless EV charging

IEEE Trans. Power Electron., vol. 30, no.11, pp. 64-

72, 2015.

[47] -effectiveness comparison of coupler designs

Energies, vol.9, no.11, 2016.

[48]

and constant voltage charge of inductive power transfer systems

with the double-sided LCC compensation topology for electric

IEEE Trans Power

Electron., vol 33, Sept. 2018.

[49]

IEEE

Electrification Mag., 2013.

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/

Author Name: Preparation of Papers for IEEE Access (February 2017)

2 VOLUME XX, 2017

[50] S. Li, Z. Liu, H. Zhao, L. Zhu, C. Shuai and Z. Chen, "Wireless

Power Transfer by Electric Field Resonance and Its Application

in Dynamic Charging," in IEEE Transactions on Industrial

Electronics, vol. 63, no. 10, pp. 6602-6612, Oct. 2016, doi:

10.1109/TIE.2016.2577625.

[51] B. Singh, B. N. Singh, A. Chandra, K. Al-Haddad, A. Pandey,

-phase improved power

quality AC IEEE Trans. Ind. Electron., vol. 50,

no. 5, pp. 962 981, Oct. 2003.

[52] -to-

grid regulation services of unidirectional charging of electric

Proc. IEEE Energy Convers. Congr. Expo., Sep.

2011, pp. 827 834.

[53] G. Kissel, SAE J1772 Update for IEEE Standard 1809 Guide for

Electric-Sourced Transportation Infrastructure Meeting, Standard

SAE J1772, SAE International, Sep. 2010.

[54] M. Y. Metwly, M. S. Abdel-Majeed, A. S. Abdel-Khalik, R. A.

Hamdy, M. S. Hamad and S. Ahmed, "A Review of Integrated

On-Board EV Battery Chargers: Advanced Topologies, Recent

Developments and Optimal Selection of FSCW Slot/Pole

Combination," in IEEE Access, vol. 8, pp. 85216-85242, 2020,

doi: 10.1109/ACCESS.2020.2992741.

[55] T. Chen et al., "A Review on Electric Vehicle Charging

Infrastructure Development in the UK," in Journal of Modern

Power Systems and Clean Energy, vol. 8, no. 2, pp. 193-205,

March 2020, doi: 10.35833/MPCE.2018.000374.

[56] A. Salem and M. Narimani, "A Review on Multiphase Drives for

Automotive Traction Applications," in IEEE Transactions on

Transportation Electrification, vol. 5, no. 4, pp. 1329-1348, Dec.

2019, doi: 10.1109/TTE.2019.2956355.

[57]

bidirectional battery charger for electric vehicles using

Proc. IEEE Veh. Power

Propulsion Conf., Sep. 2010, pp. 1 6.

[58]

power isolated bi-directional DC-DC converters for PHEV/EV

Proc. IEEE Energy Conversion

Congr. Expo., Sep. 2011, pp. 553 560.

[59] E. Sortomme and M. El-

for unidirectional vehicle-to- IEEE Trans. Smart Grid, vol.

2, no. 1, pp. 131 138, Mar. 2011.

[60]

bidirectional AC/DC and DC/DC converter for plug-in hybrid

Proc. IEEE Veh. Power Propulsion Conf.,

Sep. 2011, pp. 1 6.

[61] erformance of a

bidirectional isolated DC DC converter for a battery energy

IEEE Trans. Power Electron., vol. 27, no. 3, pp.

1237 1248, Mar. 2012.

[62]

electrification of transportation

IEEE Trans. Ind. Inf., vol. 8, no. 1, pp. 1 10, Feb. 2012.

[63] in Proc. Electric

Power Res. Inst. (EPRI), CPUC Electric Veh. Workshop, Mar.

2010.

[64] SAE Electric Vehicle Inductive Coupling Recommended

Practice, SAE 5-1773, Feb. 1, 1995.

[65] De-

multiphase electric drive and fast battery charger for electric

in Proc. IEEE Veh. Power and Propulsion Conf., Sep.

2010, pp. 1 6.

[66] D. P. Tuttle -in electric

IEEE Trans. Smart Grid, vol. 3, no. 1,

pp. 500 505, Mar. 2012.

[67]

[Online]. Available:

http://chademo.com/01_What_is_CHAdeMO.html

[68] -

Available:http://www1.eere.energy.gov/vehiclesandfuels/avta/lig

ht_duty/fsev/fsev_battery.chargers

[69] ric

IEEE Trans. Smart Grid, vol. 3, no. 1,

pp. 394 403, Mar. 2012.

[70] -stage

power factor corrector with a boost type input-current-

IEEE Trans. Power Electron., vol. 16, no. 3, pp. 360 368, May

2001.

[71]

Proc. IEEE Int. Conf. Ind. Appl., Sao Paulo, Brazil, Nov. 2010,

pp. 1 6.

[72] F. Musavi, W. Eberle -performance

single phase bridgeless interleaved PFC converter for plug-in

IEEE Trans. Ind.

Electron., vol. 47, no. 4, pp. 1833 1843, Aug. 2011.

[73] F. Musavi, W. Eberle, and W. G. Dunford,

semi-bridgeless boost power factor corrected converter for plug-

Proc. IEEE Appl.

Power Electron. Conf. Expo., Fort Worth, TX, Mar. 2011, pp.

821 828.

[74] D. C. Erb, O. C. Onar, and A. Khaligh, -directional charging

topologies for plug- Proc. IEEE

Appl. Power Electron. Conf. Expo., Feb. 21-25, 2010, pp. 2066

2072.

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/

Author Name: Preparation of Papers for IEEE Access (February 2017)

2 VOLUME XX, 2017

[75] Y. Du, S. Lukic

power isolated bi-directional dc/dc converters for PHEV/EV DC

Proc. IEEE Energy Convers. Congr.

Expo., Phoenix, AZ, Sep. 2011, pp. 553 560.

[76] D. Gautam, F. Musavi, M. Edington, W. Eberle, and W. G.

-board 3.3 kW battery charger for

in Proc. IEEE Veh. Power Propulsion Conf.,

Chicago, IL, Sep. 2011, pp. 1 6.

[77] D. Gautam, F. Musavi, M. Edington, W. Eberle, and W. G.

ing full-bridge DC DC

converter with capacitive output filter for a plug-in-hybrid

in Proc. IEEE Appl. Power

Electron. Conf. Expo., Orlando, FL, May 2012, pp. 1381 1386.

[78] -board battery charger

for PHEV without high- Electron.

Lett., vol. 46, no. 25, pp. 1691 1692, Dec. 2010.

[79] H. J. Chae, W. Y. Kim, S. Y. Yun, Y. S. Jeong, J. Y. Lee, and H.

Proc. Int. Conf. Power Electron., Shilla Jeju, Korea, Jun. 2011,

pp. 2717 2719.

[80] J. S. Kim, G.-Y. Choe, H.-M. Jung, B.-K. Lee, Y.-J. Cho, and K.-

-efficiency on-

board battery charger for electric vehicles with frequency control

Proc. IEEE Veh. Power Propulsion Conf., Lille,

France, Sep. 2010, pp. 1 6.

[81]

bidirectional ac/dc and dc/dc converter for plug-in hybrid electric

IEEE Trans. Veh. Technol., vol. 58, no. 8, pp. 3970

3980, Oct. 2009.

[82]

bidirectional power electronic converter with multi-level AC

DC/DC AC converter and non-inverted buck-boost converter for

PHEVs with minimal grid lev

Power Propulsion Conf., Sep. 1-3, 2010, pp. 1 6.

[83]

bidirectional ac/dc and dc/dc converter for plug-in hybrid electric

Proc. IEEE Veh. Power Propulsion Conf., Sep. 6 9,

2011, pp. 1 6.

[84] -

board charger topology for electric vehicles and plug-in hybrid

Proc. Appl. Power Electron. Conf., Feb.

2012, pp. 2611 2616.

[85] S. Dusmez and -3

on- Proc. Appl. Power Electron. Conf.,

Feb. 5-8, 2012, pp. 2121 2127.

[86]

battery charger with power factor correction for el

IEEE Trans. Power Electron., vol. 25, no. 3, pp. 751 759, Mar.

2010.

[87]

reluctance motor drive using three- IEEE

Trans. Ind. Electron., vol. 58, no. 5, pp. 1763 1775, May 2011.

[88]

U.S. Patent 5 341 075, Aug. 23, 1994.

[89] -wheel

IEEE Trans. Ind. Appl., vol. 31, no. 5, pp.

1096 1099, Sep./Oct. 1995.

[90] -board charger for electric

IEEE Trans. Veh. Technol., vol. 50,

no. 1, pp. 144 149, Jan. 2001.

[91] E. Loveday. Rare Look Inside Tesla Supercharger.

Accessed: Jul. 10, 2021. [Online]. Available:

https://insideevs.com/news/322486/rare-look-inside-tesla-

supercharger/

[92] Plugs, Socket-Outlets, Vehicle Connectors and Vehicle Inlets

Conductive Charging of Electric Vehicles Part 3: Dimensional

Compatibility and Interchangeability Requirements for D.C. and

A.C./D.C. Pin and Contact-Tube Vehicle Couplers, Standard IEC

62196-3:2014, Jun. 2014, p. 1.

[93] A. Yoshida. Chademo Quick Charger Connector with Excellent

Operability.

Accessed: Nov. 15, 2019. [Online]. Available:

https://globalsei.com/technology/tr/bn84/pdf/84-05.pdf

[94] A. Burnham et al. infrastructure and

J. Power Sources, vol. 367, pp. 237

249, Nov. 2017.

[95] Electric Vehicle Conductive Charging System Part 1:

GeneralRequirements, Standard IEC 61851-1:2017, Feb. 2017,

pp. 1 287.

[96] Electric Vehicle Conductive Charging System Part 23: DC

Electric Vehicle Charging Station, Standard IEC 61851-23:2014,

Mar. 2014, pp. 1 159.

[97] Electric Vehicle Conductive Charging System Part 24: Digital

Communication Between A D.C. EV Charging Station and an

Electric Vehicle for Control of D.C. Charging, Standard IEC

61851-24:2014, Mar. 2014, pp. 1 63.

[98] -Rapid

Electric Car Charging Station?

[Online]. Available:

https://www.drivezero.com.au/charging/whats-involved-in-the-

construction-of-an-ultra-rapidelectric-car-charging-station/

[99] M. S. Agamy et al. r processing

IEEE Trans.

Power Electron., vol. 29, no. 2, pp. 674 686, Feb. 2014.

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/

Author Name: Preparation of Papers for IEEE Access (February 2017)

2 VOLUME XX, 2017

[100] -efficiency DC-DC

IEEE Trans.

Power Electron., vol. 26, no. 8, pp. 2095 2100, Aug. 2011.

[101]

power DC-DC converter for electric vehicle fast charging

Proc. 43rd Annu. Conf. IEEE Ind. Electron. Soc.

(IECON), Oct. 2017, pp. 5274 5279.

[102] V. M. Iyer, S. Gulur, G. Gohil and S. Bhattacharya, "An

Approach Towards Extreme Fast Charging Station Power

Delivery for Electric Vehicles with Partial Power Processing," in

IEEE Transactions on Industrial Electronics, vol. 67, no. 10, pp.

8076-8087, Oct. 2020, doi: 10.1109/TIE.2019.2945264.

[103]

Albuquerque, NM, USA, Tech. Rep. SAND2018-8853, 2018.

[104] D. Salomonsson, L. Söde

IEEE Trans. Power Del., vol. 24, no. 3,

App. 1045 1053, Jul. 2009.

[105] D. M. Bui, S. Chen, C. Wu, K. Lien, C. Huang, and K. Jen,

of an effective protection coordination system for DC

in Proc. IEEE PES Asia Pacific Power Energy Eng.

Conf. (APPEEC), Dec. 2014, pp. 1 10.

[106] J.-

voltage DC- s. Power Del., vol.

28, no. 2, pp. 779 787, Apr. 2013.

[107] -phase PFC

rectifier systems IEEE Trans. Power Electron., vol. 28,

no. 1, pp. 176 198, Jan. 2013.

[108] D. Aggeler, F. Canales, H. Zelaya-De La Parra, A. Coccia, N.

-fast DC-charge infrastructures

Proc. IEEE PES

Innov. Smart Grid Technol. Conf. Eur. (ISGT Eur.), Oct. 2010,

pp. 1 8.

[109] T. Kang, C. Kim, Y. Suh, H. Park, B. Kang, an

design and control of bi-directional non-isolated DC-DC

Proc.

27th Annu. IEEE Appl.Power Electron. Conf. Expo. (APEC),

Feb. 2012, pp. 14 21.

[110] sive study of

neutral point voltage balancing problem in three-level neutral-

point- IEEE Trans.

Power Electron., vol. 15, no. 2, pp. 242 249, Mar. 2000.

[111]

vehicle charging station using a neutral point clamped converter

IEEE Trans. Ind. Electron., vol. 62, no. 4,

pp. 1999 2009, Apr. 2015.

[112]

voltage balance control for bipolar-DC-bus-fed EV charging

station with three level DC IEEE Trans. Ind.

Electron., vol. 63, no. 7, pp. 4031 4041, Jul. 2016.

[113] H. Akagi, T. Yamagishi, N. M. L. Tan, S. Kinouchi, Y.

-loss breakdown of a 750-V

100-kW 20-kHz bidirectional isolated DC DC converter using

SiC- IEEE Trans. Ind. Appl., vol.

51, no. 1, pp. 420 428, Jan. 2015.

[114] -state

IEEE

Trans. Smart Grid, vol. 10, no. 1, pp. 317 326, Jan. 2019.

[115]

a bidirectional isolated DC-DC converter for a battery energy

IEEE Trans. Power Electron., vol. 27, no. 3, pp.

1237 1248, Mar. 2012.

[116]

minimization in a bidirectional isolated DC DC converter for

IEEE Trans. Ind. Electron., vol. 61,

no. 12, pp. 6822 6831, Dec. 2014.

[117] A. Rodríguez, A. Vázquez, D. G. Lamar, M. M. Hernando, and J.

improve the performance of a dual active bridge with phase-shift

IEEE Trans. Power Electron., vol. 30, no. 2, pp. 790

804, Feb. 2015.

[118] B. Zhao -stress-

optimized switching strategy of isolated bidirectional DC DC

converter with dual-phase- IEEE Trans. Ind.

Electron., vol. 60, no. 10, pp. 4458 4467, Oct. 2013.

[119] G. Oggier, G. O. García

to operate the dual active bridge DC-DC converter under soft

IEEE Trans. Power

Electron., vol. 26, no. 4, pp. 1228 1236, Apr. 2011.

[120] -optimized high-current

IEEE

Trans. Ind. Electron., vol. 59, no. 7, pp. 2745 2760, Jul. 2012.

[121] -phase-shift

control to minimize current stress and achieve full soft-switching

of isolated bidirectional DC- IEEE Trans. Ind.

Electron., vol. 63, no. 7, pp. 4169 4179, Jul. 2016.

[122] J. Hiltunen, V. Väisänen, R. Juntunen, and P. Silventoinen,

ive

IEEE Trans. Power Electron., vol. 30, no. 12,

pp. 7138 7148, Dec. 2015.

[123] -efficiency DAB converter

IEEE Trans. Power

Electron., vol. 31, no. 3, pp. 2069 2082, Mar. 2016.

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/

Author Name: Preparation of Papers for IEEE Access (February 2017)

2 VOLUME XX, 2017

[124] A. Taylor, G. Liu, H. Bai, A. Brown, P. M. Johnson, and M.

-phase-shift control for a dual active

bridge to secure zero-voltage switching and enhance light-load

IEEE Trans. Power Electron., vol. 33, no. 6, pp.

4584 4588, Jun. 2018.

[125] DC

converter with new CLLC resonant tank featuring minimized

IEEE Trans. Ind. Electron., vol. 57, no. 9, pp.

3075 3086, Sep. 2010.

[126] Z. U. Zahid, Z. M. Dalala, R. Chen, B. Chen, and J.-S. Lai,

-DC resonant converter for vehicle-

to- IEEE Trans. Transport. Electrific.,

vol. 1, no. 3, pp. 232 244, Oct. 2015.

[127] J.-H. Jung, H.-S. Kim, M.-H. Ryu, and J.-W. Baek

methodology of bidirectional CLLC resonant converter for high-

IEEE Trans.

Power Electron., vol. 28, no. 4, pp. 1741 1755, Apr. 2013.

[128] -frequency

transformer design for modular power conversion from medium-

IEEE Trans. Power Electron., vol. 33,

no. 9, pp. 7545 7557, Sep. 2018.

[129] C.-S. Wang, S.-H. Zhang, Y.-F. Wang, B. Chen, and J.-H. Liu,

-kW isolated high voltage conversion ratio bidirectional

CLTC resonant DC DC converter with wide gain range and high

IEEE Trans. Power Electron., vol. 34, no. 1, pp.

340 355, Jan. 2019.

[130] -

type DC transformer in the hybrid AC DC IEEE

Trans. Ind. Electron., vol. 66, no. 3, pp. 1906 1918, Mar. 2019.

[131] -efficiency

high density wide-bandgap device-based bidirectional on-board

IEEE J. Emerg. Sel. Topics Power Electron., vol. 6, no.

3, pp. 1627 1636, Sep. 2018.

[132] -bridge

in Proc.

IEEE Int. Conf. Power Electron., Drives Energy Syst. (PEDES),

Dec. 2016, pp. 1 6.

[133] -

IEEE Trans. Ind. Electron., vol. 65, no. 5, pp. 3879 3889, May

2018.

[134] F. Z. Peng, H. Li, G.- S

bidirectional DC-DC converter for fuel cell and battery

IEEE Trans. Power Electron., vol. 19, no. 1, pp.

54 65, Jan. 2004.

[135] H. Li, D. Liu, F. Z. Peng, and G.-

a dual half bridge isolated ZVS bi-directional DC-DC converter

in Proc. IEEE 36th Power

Electron. Spec. Conf., Jun. 2005, pp. 2777 2782.

[136]

digital controller for a dual half bridge isolated bi-directional

DC-DC in Proc. 21st Annu. IEEE Appl. Power

Electron. Conf. Expo. (APEC), Mar. 2006, p. 5.

[137]

DC-DC bidirectional converter made with many interleaved buck

IEEE Trans. Power Electron., vol. 21, no. 3, pp. 578

586, May 2006.

[138] J. Zhang, J.-S. Lai, R.- -power density

design of a soft-switching high-power bidirectional DC DC

IEEE Trans. Power Electron., vol. 22, no. 4, pp.

1145 1153, Jul. 2007.

[139] D. Chris -fast charging station for

in Proc. 17th

Eur. Conf. Power Electron. Appl. (EPE ECCE-Eur.), Sep. 2015,

pp. 1 11.

[140] M. T. Zhang, Y. Jiang, F. C. Lee, and M. M. Jovanovic,

phase three- in

Proc. 10th Annu. IEEE Appl. Power Electron. Conf. Expo., vol.

1, Mar. 1995, pp. 434 439.

[141] P. J. Grbovic, P. Delarue, P. Le Moigne, and P. Bartholomeus,

-level DC DC converter for the

IEEE Trans. Ind. Electron., vol. 57,

no. 10, pp. 3415 3430, Oct. 2010.

[142]

analysis of bidirectional three-level DC DC converter for

automotive applications IEEE Trans. Ind. Electron., vol. 62, no.

5, pp. 3305 3315, May 2015.

[143] R. M. Cuzner, A. R. Bendre, P. J. Faill, and B. Semenov,

-isolated three level DC/DC converter

in Proc. IEEE Ind. Appl. Annu.

Meeting, Sep. 2007, pp. 2001 2008.

[144]

eliminating circulating current of parallel three-level DC DC

converter- IEEE Trans. Ind. Electron.,

vol. 63, no. 3, pp. 1362 1371, Mar. 2016.

[145]

nonisolated bi-directional DC-DC converters for plug-in hybrid

electric vehicle charge station application at municipal parking

in Proc. 25th Annu. IEEE Appl. Power Electron. Conf.

Expo. (APEC), Feb. 2010, pp. 1145 1151.

[146]

power balance management in high-power three-level DC DC

IEEE Trans. Power

Electron., vol. 31, no. 1, pp. 89 100, Jan. 2016.

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/

Author Name: Preparation of Papers for IEEE Access (February 2017)

2 VOLUME XX, 2017

[147] -efficiency silicon carbide (SiC) converter

Proc. IEEE Energy Convers. Congr. Expo. (ECCE), Sep. 2019,

pp. 2471 2477.

[148] W. Qian, H. Cha, F. Z. Peng, and L. M. Tol -kW variable

3X DC-DC converter for plug- IEEE

Trans. Power Electron., vol. 27, no. 4, pp. 1668 1678, Apr.

2012.

[149] -state transformers Key

design challenges, applicability, and future c in Proc.

17th Int. Conf. Power Electron. Motion Control (PEMC), Varna,

Bulgaria, Sep. 2016, p. 26.

[150] -kV

single-stage solid-state transformer based on the current-fed

series resonant converter and 15- IEEE

Trans. Power Electron., vol. 34, no. 2, pp. 1099 1112, Feb.

2019.

[151]

of solid- IEEE Trans.

Smart Grid, vol. 3, no. 2, pp. 975 985, Jun. 2012.

[152] Frauke Heider MB, et al. Vehicle to Grid: realization of power

management for the optimal integration of plug-in electric

vehicles into the grid. In: EVS24 international battery, hybrid and

fuel cell electric vehicle symposium stavanger, Norway; 2009.

pp.1-12.

[153] S. Deb, K. Kalita and P. Mahanta, "Review of impact of electric

vehicle charging station on the power grid," 2017 International

Conference on Technological Advancements in Power and

Energy ( TAP Energy), 2017, pp. 1-6, doi:

10.1109/TAPENERGY.2017.8397215.

[154]

Electric Vehicle Charging Station Load on Distribution

Energies, vol. 11, no. 1, p. 178, Jan. 2018.

[155] Gamboa G, et al. Control strategy of a multi-port, grid connected,

direct-DC PV charging station for plug-in electric vehicles. In:

Energy Conversion Congress and exposition (ECCE). IEEE;

2010.

[156] Deb S, Tammi K, Kalita K, Mahanta P. Review of recent trends

in charging infrastructure planning for electric vehicles. WIREs

Energy Environ. 2018; pp.306. https://doi.org/10.1002/wene.306

[157] S. M. Shariff, M. S. Alam, F. Ahmad, Y. Rafat, M. S. J. Asghar

and S. Khan, "System Design and Realization of a Solar-Powered

Electric Vehicle Charging Station," in IEEE Systems Journal,

vol. 14, no. 2, pp. 2748-2758, June 2020, doi:

10.1109/JSYST.2019.2931880.

[158] Onar O C, Khaligh A. Grid interactions and stability analysis of

distribution power network with high penetration of plug-in

hybrid electric vehicles. In: Applied power electronics

conference and Exposition (APEC). Twenty-Fifth Annual IEEE;

2010.

[159] Das T, Aliprantis DC. Small-signal stability analysis of power

system integrated with PHEVs. In: Energy 2030 conference,

2008. ENERGY 2008. IEEE; 2008.

[160] Jingyu Y, et al. Battery fast charging strategy based on model

predictive control. In: Vehicular technology conference fall (VTC

2010-fall). IEEE 72nd; 2010. pp. 1-8.

[161] D. Z. B. Wang, P. Dehghanian, Y. Tian and T. Hong,

"Aggregated Electric Vehicle Load Modeling in Large-Scale

Electric Power Systems", IEEE Transactions on Industry

Applications, pp. 5796-5810, 2020.

[162] U. C. Chukwu, "The Impact of Load Patterns on Power Loss: A

case of V2G in the Distribution Network," 2020 Clemson

University Power Systems Conference (PSC), 2020, pp. 1-4, doi:

10.1109/PSC50246.2020.9131314.

[163] U. C. Chukwu, "The Impact of V2G on Power Factors," 2020

Clemson University Power Systems Conference (PSC), 2020, pp.

1-4, doi: 10.1109/PSC50246.2020.9131328.

[164] V system impacts of large scale

Universities

power engineering conference (AUPEC), 2010 20th australasian;

2010.

[165] K. Kaur, S. Garg, G. Kaddoum, S. H. Ahmed, F. Gagnon and M.

Atiquzzaman, "Demand-Response Management Using a Fleet of

Electric Vehicles: An Opportunistic-SDN-Based Edge-Cloud

Framework for Smart Grids," in IEEE Network, vol. 33, no. 5,

pp. 46-53, Sept.-Oct. 2019, doi: 10.1109/MNET.001.1800496.

[166] power

Vehicle power and propulsion

conference, 2009, IEEE; 2009.

[167] -in hybrid electric vehicles on

Innovative technologies for

an efficient and reliable electricity supply (CITRES). IEEE

Conference on 2010.

[168] H. Yano, K. Kudo, T. Ikegami, H. Iguchi, K. Kataoka and K.

Ogimoto, "A novel charging-time control method for numerous

EVs based on a period weighted prescheduling for power supply

and demand balancing," 2012 IEEE PES Innovative Smart Grid

Technologies (ISGT), 2012, pp. 1-6, doi:

10.1109/ISGT.2012.6175612.

[169] S. Canevese, D. Cirio, M. Gallanti and A. Gatti, "EV Flexibility

Supply via Participation in Balancing Services: Possible

Profitability for Italian End Users," 2019 AEIT International

Annual Conference (AEIT), 2019, pp. 1-6, doi:

10.23919/AEIT.2019.8893332.

[170] I. S. Bayram, G. Michailidis and M. Devetsikiotis, "Unsplittable

Load Balancing in a Network of Charging Stations Under QoS

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/

Author Name: Preparation of Papers for IEEE Access (February 2017)

2 VOLUME XX, 2017

Guarantees," in IEEE Transactions on Smart Grid, vol. 6, no. 3,

pp. 1292-1302, May 2015, doi: 10.1109/TSG.2014.2362994.

[171] M. A. H. Rafi and J. Bauman, "A Comprehensive Review of DC

Fast-Charging Stations With Energy Storage: Architectures,

Power Converters, and Analysis," in IEEE Transactions on

Transportation Electrification, vol. 7, no. 2, pp. 345-368, June

2021, doi: 10.1109/TTE.2020.3015743.

[172] O. Beaude, S. Lasaulce, M. Hennebel and I. Mohand-Kaci,

"Reducing the Impact of EV Charging Operations on the

Distribution Network," in IEEE Transactions on Smart Grid, vol.

7, no. 6, pp. 2666-2679, Nov. 2016, doi:

10.1109/TSG.2015.2489564.

[173] N. Rodrigues, J. Sharma, S. Vyas and A. Datta, "A Regulated

Electric Vehicle Charging Scheme in Coordination with Utility

Pricing and Transformer Loading," 2019 IEEE Transportation

Electrification Conference (ITEC-India), 2019, pp. 1-5, doi:

10.1109/ITEC-India48457.2019.ITECINDIA2019-135.

[174] S. A. A. Rizvi, A. Xin, A. Masood, S. Iqbal, M. U. Jan and H.

Rehman, "Electric Vehicles and their Impacts on Integration into

Power Grid: A Review," 2018 2nd IEEE Conference on Energy

Internet and Energy System Integration (EI2), 2018, pp. 1-6, doi:

10.1109/EI2.2018.8582069.

[175]

charging system for a large parking de Industry applications

society annual meeting, 2009. IAS 2009. IEEE; 2009, pp.1-6.

[176]

Universities power engineering conference (UPEC) 2010, pp. 1-

[177] A. Hajimiragha, C. A. Canizares, M. W. Fowler and A. Elkamel,

"Optimal Transition to Plug-In Hybrid Electric Vehicles in

Ontario, Canada, Considering the Electricity-Grid Limitations,"

in IEEE Transactions on Industrial Electronics, vol. 57, no. 2,

pp. 690-701, Feb. 2010, doi: 10.1109/TIE.2009.2025711.

[178] H. Ramadan, A. Ali and C. Farkas, "Assessment of plug-in

electric vehicles charging impacts on residential low voltage

distribution grid in Hungary," 2018 6th International Istanbul

Smart Grids and Cities Congress and Fair (ICSG), 2018, pp.

105-109, doi: 10.1109/SGCF.2018.8408952.

[179] -term electric system investments to

support plug- Power and energy

society general meeting - conversion and delivery of electrical

energy in the 21st century. IEEE, 2008; 2008, pp.1-6.

[180]

43rd Hawaii international

conference on. System Sciences (HICSS); 2010, pp. 1-10.

[181] L. Pieltain Fernández, T. Gomez San Roman, R. Cossent, C.

Mateo Domingo and P. Frías, "Assessment of the Impact of Plug-

in Electric Vehicles on Distribution Networks," in IEEE

Transactions on Power Systems, vol. 26, no. 1, pp. 206-213, Feb.

2011, doi: 10.1109/TPWRS.2010.2049133.

[182] V. Zdraveski, P. Krstevski, J. Vuletic, J. Angelov, A. K. Mateska

and M. Todorovski, "Analyzing the Impact of Battery Electric

Vehicles on Distribution Networks Using Nondeterministic

Model," IEEE EUROCON 2019 -18th International Conference

on Smart Technologies, 2019, pp. 1-7, doi:

10.1109/EUROCON.2019.8861984.

[183] E. Veldman, M. Gibescu and A. Postma, "Unlocking the hidden

potential of electricity distribition grids," CIRED 2009 - 20th

International Conference and Exhibition on Electricity

Distribution - Part 1, 2009, pp. 1-4.

[184] J. Schlee, A. Mousseau, J. Eggebraaten, B. Johnson, H. Hess and

B. Johnson, "The effects of plug-in electric vehicles on a small

distribution grid," 41st North American Power Symposium, 2009,

pp. 1-6, doi: 10.1109/NAPS.2009.5484055.

[185] P. B. Evans, S. Kuloor and B. Kroposki, "Impacts of plug-in

vehicles and distributed storage on electric power delivery

networks," 2009 IEEE Vehicle Power and Propulsion

Conference, 2009, pp. 838-846, doi:

10.1109/VPPC.2009.5289761.

[186] J. A. P. Lopes, F. J. Soares, P. M. R. Almeida, P. C. Baptista, C.

M. Silva and T. L. Farias, "Quantification of technical impacts

and environmental benefits of electric vehicles integration on

electricity grids," 2009 8th International Symposium on

Advanced Electromechanical Motion Systems & Electric Drives

Joint Symposium, 2009, pp. 1-6, doi:

10.1109/ELECTROMOTION.2009.5259139.

[187] M. Tabari and A. Yazdani, "A DC distribution system for power

system integration of Plug-In Hybrid Electric Vehicles," 2013

IEEE Power & Energy Society General Meeting, 2013, pp. 1-5,

doi: 10.1109/PESMG.2013.6672772.

[188] J. A. Orr, A. E. Emanuel and D. G. Pileggi, "Current Harmonics,

Voltage Distortion, and Powers Associated with Battery Chargers

Part I: Comparisons Among Different Types of Chargers," in

IEEE Transactions on Power Apparatus and Systems, vol. PAS-

101, no. 8, pp. 2703-2710, Aug. 1982, doi:

10.1109/TPAS.1982.317641.

[189] T. Song, P. Wang, Y. Zhang, F. Gao, Y. Tang and S. Pholboon,

"Suppression Method of Current Harmonic for Three-Phase

PWM Rectifier in EV Charging System," in IEEE Transactions

on Vehicular Technology, vol. 69, no. 9, pp. 9634-9642, Sept.

2020, doi: 10.1109/TVT.2020.3005173.

[190] L. Kütt, E. Saarijärvi, M. Lehtonen, H. Mõlder and J. Niitsoo,

"Harmonic distortions of multiple power factor compensated EV

chargers," 2014 16th European Conference on Power Electronics

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/

Author Name: Preparation of Papers for IEEE Access (February 2017)

2 VOLUME XX, 2017

and Applications, 2014, pp. 1-7, doi:

10.1109/EPE.2014.6911035.

[191] A. Megha, N. Mahendran and R. Elizabeth, "Analysis of

Harmonic Contamination in Electrical Grid due to Electric

Vehicle Charging," 2020 Third International Conference on

Smart Systems and Inventive Technology (ICSSIT), 2020, pp.

608-614, doi: 10.1109/ICSSIT48917.2020.9214096.

[192] L. Kütt, E. Saarijärvi, M. Lehtonen, H. Mõlder and J. Niitsoo,

"Electric vehicle charger load current harmonics variations due to

supply voltage level differences Case examples," 2014

International Symposium on Power Electronics, Electrical

Drives, Automation and Motion, 2014, pp. 917-922, doi:

10.1109/SPEEDAM.2014.6872009.

[193] S. Rahman and G. B. Shrestha, "An investigation into the impact

of electric vehicle load on the electric utility distribution system,"

in IEEE Transactions on Power Delivery, vol. 8, no. 2, pp. 591-

597, April 1993, doi: 10.1109/61.216865.

[194] K. Clement, E. Haesen and J. Driesen, "Stochastic analysis of the

impact of plug-in hybrid electric vehicles on the distribution

grid," CIRED 2009 - The 20th International Conference and

Exhibition on Electricity Distribution - Part 2, 2009, pp. 1-7.

[195] H. Wu, M. Shahidehpour, A. Alabdulwahab and A. Abusorrah,

"A Game Theoretic Approach to Risk-Based Optimal Bidding

Strategies for Electric Vehicle Aggregators in Electricity Markets

With Variable Wind Energy Resources," in IEEE Transactions

on Sustainable Energy, vol. 7, no. 1, pp. 374-385, Jan. 2016, doi:

10.1109/TSTE.2015.2498200.

[196] M. C. Falvo, D. Sbordone, I. S. Bayram, and M. Devetsikiotis,

"EV charging stations and modes:International standards," in

2014 International Symposium on Power Electronics, Electrical

Drives, Automation and Motion, 2014, pp. 1134-1139.

[197] Society of Automation Engineering - Interantional Standards on

EV Charging Stations. Available: https://www.sae.org/

[198] "IEEE standard for interconnection and interoperability of

distributed energy resources with associated electric power

systems interfaces," IEEE Std, pp. 1547-2018, 2018.

[199] U. Laboratories. Electric Vehicle Infrastrucure Services - UL.

Available: https://www.ul.com/services/electric-vehicle-ev-

infrastructure-services

[200] N. F. P. Association, NFPA 70: National Electrical Code.

National Fire Protection Assoc., 2011.

[201] Electric Vehicle Charging Stations - Standards. Available:

https://www.iso.org/standards.html

[202] CHAdeMO protocol development. 2018. Available:

https://www.chademo.com/activities/protocol-development/

[203] A. Oran, "Top 10 countries in the global EV revolution: 2018

edition," insideevs. com, 2019.

[204] IEC-Electric Vehicles Charging Stations.

Available: https://www.iec.ch/transportation/electricvehicles

Unraveling the Smart Charging Technologies, Energy Sources, and Regulatory Standards for EVs

Article

Full-text available

Jan 2025

Electric Vehicles (EVs) are anticipated to be pivotal contributors to the global energy transformation in the automobile industry, ignited by their rapid proliferation. However, the widespread integration of EVs requires rigorous research and synthesis in charging solutions and EV supply equipment to meet the expected performance and improve ancillary services. Analysing the current landscape of EV charging technologies is essential to accelerate EV adoption, incorporating advanced control strategies to mitigate negative impacts and improve charging efficiency. Thus, this study presents a meticulous review that culminates in a curated anthology of 81 pivotal articles, with a predominant emphasis on charging EVs and associated technologies. The findings constitute extensive potential in this domain and we have carefully scrutinised the research studies to discern potential EV charging technologies, encompassing their taxonomy, on-board and off-board charging infrastructures, and the global standards regulating EV charging systems. The revelations of the study elucidate the prevailing paradigms within the EV research nexus, charting a course for future scholarly pursuits and practical applications.

Viability and impact of existing urban minibus taxi mobility with electric vehicles

Article

Full-text available

Jan 2025

Sub-Sahara’s paratransit sector is yet to take off in the electrification of its minibus taxis. More than two thirds of daily commuters are transported by minibus taxis in cities. However, the electrification process is prohibited by multiple factors, such as an already fragile grid network, and an energy scarcity in the region. Planning for eventual electrification is further complicated by the sector’s unique, decentralised, unscheduled, and demand-driven nature. We use the concepts of vehicle-day and fleet-day to quantify the relationship between mobility and electricity demand, which are linked by the charging infrastructure and charging strategies. To investigate the effects of the charging requirements, data from 17 minibus taxis in Stellenbosch, South Africa was used with a bespoke software built to simulate the driving and charging of the taxis. Different charging rates (7.2 kW, 22 kW and 50 kW) were tested as well as having different charging locations, that of the depot and home and a combination of the two. The effectiveness of each scenario is assessed on the success rate of the vehicle-days. A depot charging rate of 22 kW had a success rate of 55%, with the furthest a vehicle can travel being 200 km. This increases with home charging to a 79% success rate (250 km), and can be further increased with 50 kW charging and home charging to 86% success rate (280 km). However, home-only charging provides comparable results and should be a consideration in the electric transition.

Profiling Electric Vehicles via Early Charging Voltage Patterns

Preprint

Full-text available

Jun 2025

Electric Vehicles (EVs) are rapidly gaining adoption as a sustainable alternative to fuel-powered vehicles, making secure charging infrastructure essential. Despite traditional authentication protocols, recent results showed that attackers may steal energy through tailored relay attacks. One countermeasure is leveraging the EV's fingerprint on the current exchanged during charging. However, existing methods focus on the final charging stage, allowing malicious actors to consume substantial energy before being detected and repudiated. This underscores the need for earlier and more effective authentication methods to prevent unauthorized charging. Meanwhile, profiling raises privacy concerns, as uniquely identifying EVs through charging patterns could enable user tracking. In this paper, we propose a framework for uniquely identifying EVs using physical measurements from the early charging stages. We hypothesize that voltage behavior early in the process exhibits similar characteristics to current behavior in later stages. By extracting features from early voltage measurements, we demonstrate the feasibility of EV profiling. Our approach improves existing methods by enabling faster and more reliable vehicle identification. We test our solution on a dataset of 7408 usable charges from 49 EVs, achieving up to 0.86 accuracy. Feature importance analysis shows that near-optimal performance is possible with just 10 key features, improving efficiency alongside our lightweight models. This research lays the foundation for a novel authentication factor while exposing potential privacy risks from unauthorized access to charging data.

Review on optimal planning and operation of charging stations for electric vehicles

Article

Full-text available

Jun 2025

Several factors need to be taken into account while planning the locations of electric vehicle charging stations. The thoughtful design and arrangement of charging stations, as a crucial component of the infrastructure supporting electric vehicles, is essential for the advancement of these kinds of vehicles. However, a number of intricate aspects, including policy economics, charging demand, user comfort when charging, and traffic circumstances, influence the design and arrangement of charging stations. With the goal to uncover competing interests and opportunities for collaboration in the operation and development of charging infrastructure, this study intends to assist researchers and technology developers in investigating cutting-edge techniques from the viewpoint of each constituent. Additionally, only a strong electric vehicle charging station (EVCS) infrastructure may provide some of the answers to the most basic EV concerns, like EV cost and range. The literature claims that several sorts of techniques, objective functions, and constraints for issue formulation have been used by the scholars. In addition, sensitivity analysis, vehicle to grid strategy, integration of distributed generation, charging kinds, objective functions, restrictions, EV load modelling, uncertainty, and optimization methodologies are examined for the most recent research publications. Discussions occur as well regarding the effects of the EV load on the distribution network, the environment, and the economy.

A new SiC-based 1.8-kW 9-level buck PFC rectifier with single/multiple output capabilities for EV charging applications

Article

Full-text available

May 2025
ELECTR ENG

This article presented a novel silicon carbide (SiC)-based boost-packed nine-level (9L) bidirectional buck power factor correction (9L-BBPFC) rectifier, designed to optimize efficiency and enhance power quality. The operation of the proposed 9L-BBPFC topology significantly lessens the total harmonic distortion (THD) in the input current and mitigates voltage stress across switches. With its bidirectional power flow capability, the rectifier is well-suited for diverse DC-load applications, supporting both single and multiple loads, which may be identical or different loads. The series–parallel capacitor switching mechanism ensures automatic voltage balancing across varying load conditions, simplifying control strategy and improving system stability under dynamic operation with fewer sensors. Significantly, the rectifier exhibits fault-tolerant operation, maintaining consistent output power during open-circuit faults, comparable to its performance in healthy mode. Detailed analyses of modulation technique, control strategy, component ratings, power losses, and topology assessments are provided. Experimental validation is done with an experimental setup of 1.8 kW, confirming the rectifier’s superior performance, achieving an optimal efficiency of 98.63%, a THD of 2.53%, and a unity power factor at rated condition. The results demonstrate that the proposed 9L-BBPFC rectifier is a highly efficient and reliable solution for PFC, offering robust operation even in fault conditions, and making it an attractive solution for modern power electronics systems.

Impacts of Electric Vehicle Charging System on the Distribution Grid and Remedial Measures

Conference Paper

Oct 2024

Design and Hardware Implementation of Dynamic Coil Alignment in Static Wireless EV Charging

Conference Paper

Apr 2025

A Comprehensive review on AIoT applications for intelligent EV charging/discharging ecosystem

Article

Jun 2025

As a prompt solution to air pollution, global warming, and fossil fuel shortages, electric vehicle (EV) penetration has been massively increasing. Spontaneously, higher EV utilization increases electricity demand. With the advent of vehicle-to-grid (V2G) technology, EVs play the prosumers’ role in the power system. However, this role necessitates an intelligent EV charging ecosystem (IEVC-eco) that coordinates all components effectively, transforming EVs from a potential threat of power system overload into a valuable resource for ancillary services. AI and IoT (AIoT) are robust technologies, and with their contribution, the idea of IEVC-eco will become true. Therefore, in this paper, in addition to the IEVC-eco elements and tool determination, we investigate their AIoT requirements, including communication protocols, standards, and optimization techniques. Additionally, due to the importance of electric vehicle charging station (EVCS) recommendation tools, we endeavor to provide an efficient framework as a versatile gadget that considers all IEVC-eco stakeholders’ desires.

Investigating power quality issues in electric buggy battery charger systems: analysis and mitigation strategies

Article

Full-text available

Jun 2025

This paper investigates power quality issues in the battery charger system of an electric buggy. Key power quality parameters such as total harmonic distortion (THD), power factor (PF), input voltage, and input current, were measured and analyzed during the charging process. The findings reveal significant power quality challenges, with THD levels exceeding IEEE 519 standards, indicating inefficiencies and potential risks such as increased heating and stress on charger components. Power factor readings reveal a substantial reactive power component, further contributing to inefficiency. To address these issues, the study recommends implementing harmonic mitigation techniques, such as passive and active filters, to reduce THD levels, using power factor correction methods, and optimizing charging algorithms to manage power demand more effectively. Continuous monitoring of charging parameters is essential for maintaining optimal performance and reliability. Adhering to standards is crucial for the efficient and reliable operation of electric vehicle (EV) charging systems, with regular compliance testing and benchmarking necessary to identify improvement areas and maintain a high-quality charging infrastructure. The proposed solutions aim to develop a sustainable and efficient charging system for electric buggies, providing valuable insights and recommendations for future research and development in power electronics and drive systems for EV applications.

Single Phase Fast EV Charger Based on Grid Connected Quasi Z-Source Inverter

Conference Paper

Dec 2024

DC-DC Converters for Transportation Electrification: Topologies, Control, and Future Challenges

Article

Full-text available

Jun 2021

DC-DC CONVERTERS ARE SOLID-STATE DC "transformers" that convert one type of dc electricity into another via power electronic circuits. They have been used in a broad range of applications, from IT devices (such as a power supply to provide different dc voltage levels inside a personal computer or a data center server) to medical equipment (e.g., a solar charger for a cardiac pacemaker) and from consumer electronics (e.g., chargers for various smart mobile devices) to high-power industrial applications, which is the focused area of this article. As there has been exponential growth in transportation electrification since the beginning of the 21st century, dc-dc converters have become one of the core devices in electric and autonomous vehicles. Extensive research and development efforts have been made on the design and implementation of dc-dc converters, aiming at higher power density, higher efficiency, and more reduction in cost. In this article, various dc-dc converter topologies and control methodologies for transportation electrification are reviewed. The challenges and future development trends for creating the next-generation dc-dc power converters are also discussed.

Suppression Method of Current Harmonic for Three-Phase PWM Rectifier in EV Charging System

Article

Full-text available

Jun 2020

Under the unbalanced condition of grid voltages, the second-order harmonic voltage ripple will appear on the DC bus of the three-phase PWM rectifier due to the existence of the negative sequence voltages. In addition, the total harmonic distortion (THD) of the grid currents will increase correspondingly. In this paper, the coupling mechanism between the DC bus voltage ripple and the grid harmonic currents is revealed. Based on the situation above, a grid harmonic current suppression method is proposed. Compared with existing methods, the proposed method has the advantages in the following three aspects. Firstly, the proposed method does not require either the extraction of positive/negative sequence or the positive/negative sequence current control, which can highly reduce the complexity of the system. Secondly, the grid current harmonics can be reduced by an improved proportional quasi resonant (IPQR) controller. Thirdly, the IPQR controller has little effect on the parameter design of the control system, which facilitates the control design. Finally, the experiments show the accuracy of the theoretical analysis and the effectiveness of the proposed method.

A Review of Integrated On-Board EV Battery Chargers: Advanced Topologies, Recent Developments and Optimal Selection of FSCW Slot/Pole Combination

Article

Full-text available

May 2020

Integrated on-board battery chargers (OBCs) have been recently introduced as an optimal/elegant solution to increase electric vehicle (EV) market penetration as well as minimize overall EV cost. Unlike conventional off-board and on-board battery chargers, integrated OBCs exploit the existing propulsion equipment for battery charging without extra bulky components and/or dedicated infrastructure. OBCs are broadly categorized into three-phase and single-phase types with unidirectional or bidirectional power flow. This paper starts with surveying the main topologies introduced in the recent literature employing either induction or permanent magnet motors to realize fully integrated slow (single-phase) and fast (three-phase) on-board EV battery charging systems, with emphasis on topologies that entail no or minimum hardware reconfiguration. Although, permanent magnet (PM) motors with conventional double-layer distributed winding layouts have been deployed in most commercial EV motors, the non-overlapped fractional slot concentrated winding (FSCW) has been the prevailing choice in the most recent permanent magnet motor designs due to its outstanding operational merits. Hence, a thorough investigation of the impact different FSCW stator winding designs have on machine performance under the charging process is presented in this paper. To this end, the induced magnet losses, which represent a challenging demerit of the FSCW, have been used to compare different topologies under both propulsion and charging operation modes. Based on the introduced comparative study, the optimal slot/pole combinations that correspond to the best compromise under both operational modes have been highlighted.

Beyond the Datasheet

Article

Jul 2021

Microchip Technology reveals the key benefits of silicon carbide (SiC) semiconductors, including improved system efficiency, reduced power electronics costs, and the ability to support higher operating temperatures

Analysis of Harmonic Contamination in Electrical Grid due to Electric Vehicle Charging

Conference Paper

Aug 2020

Datasheet

Article

Nov 2020

Philippe Darche

In general, manufacturers share technical information in two documents, the characteristic sheet or datasheet and the document describing the architecture and software operation. The datasheet is destined for the electronics technician and gives the electrical, time and mechanical specifications of the component. The electrical specifications include supply voltage, power consumption, power supply profiles, and energy consumption. The microprocessor, when powered up, is in an undetermined state. When the supply voltage has become stable and it is within a range permitted by the electrical characteristics, it is necessary to initialize the microprocessor so that its state is known. The initialization of the microprocessor is done by a time‐calibrated pulse applied to a dedicated microprocessor pin which triggers the execution of the associated initialization routine. An electronic chip can be mounted on a printed circuit without a package. This technology is called chip on board. The welded chip is protected by a resin coating.

Modern Electric, Hybrid Electric, and Fuel Cell Vehicles: Fundamentals, Theory, and Design

Book

Dec 2017

A Comprehensive Review of DC Fast-Charging Stations With Energy Storage: Architectures, Power Converters, and Analysis

Article

Aug 2020

Electric vehicle (EV) adoption continues to rise, yet EV sales still represent a small portion of vehicle sales in most countries. An expansion of the DC fast charging (DCFC) network is likely to accelerate this revolution towards sustainable transportation, giving drivers more flexible options for charging on longer trips. However, DCFC presents a large load on the grid which can lead to costly grid reinforcements and high monthly operating costs – adding energy storage to the DCFC station can help mitigate these challenges. This paper performs a comprehensive review of DCFC stations with energy storage, including motivation, architectures, power electronic converters, and a detailed simulation analysis for various charging scenarios. The review is closely tied to current state-of-the-art technologies and covers both academic research contributions and real energy storage projects in operation around the world.

The Impact of Load Patterns on Power Loss: A case of V2G in the Distribution Network

Conference Paper

Mar 2020

Uwakwe Chukwu

The Impact of V2G on Power Factors

Conference Paper

Mar 2020

Uwakwe Chukwu

A Comprehensive Review on Structural Topologies, Power Levels, Energy Storage Systems, and Standards for Electric Vehicle Charging Stations and Their Impacts on Grid

Abstract and Figures

Recommended publications

HYBRID ELECTRIC VEHICLES: TYPES AND CONTROL, A GENERAL OVERVIEW

Impacts of Renewable Sources of Energy on Bid Modeling Strategy in an Emerging Electricity Market Us...

Extreme Fast Charging of Electric Vehicles: A Technology Overview

Experimental validation of off-board EV charging station with reduced active switch count

Electric Vehicle Charging Stations and their Impact on the Power Quality of Utility Grid