Article

Sliding Mode Control of Single Phase Interleaved Totem-Pole PFC for Electric Vehicle Onboard Chargers

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Abstract

In this paper, a comprehensive sliding mode control (SMC) loop design for single-phase interleaved totem pole (ILTP) power factor correction (PFC) converters for electric vehicle (EV) onboard charger applications is proposed. The major objectives of the proposed SMC are to improve the converter dynamics, ensure a tight output voltage regulation under fast load fluctuations, and maintain a unity power factor. The sliding mode coefficients are selected to ensure both small signal and large signal stability for the robustness of the converter in wide operating conditions. As verification to the proof-of-concept, a hardware prototype of a single-phase ILTP PFC is developed and tested to validate the effectiveness of loop design by the load transient tests. The steady state results exhibit a power factor > 0.995 and total harmonic distortion (THD) < 3% at 800W load power. At a 25% step-change in load power, SMC achieves 80 ms settling time, which is approximately 200 ms faster than the conventional PI control.

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... The totem-pole bridgeless boost converter is a type of bridgeless boost converter. Among the various bridgeless boost converters, it has high efficiency and low common-mode (CM) noise compared [12][13][14][15][16][17]. But, due to the totem-pole structure of Q B1 and Q B2 , a reverse recovery current of Q B1 flows to Q B2 when Q B1 is turned on in the positive cycle, which causes large switching loss at Q B2 [18][19][20]. ...
... The totem-pole bridgeless boost converter is a type of bridgeless boost converter. Among the various bridgeless boost converters, it has high efficiency and low common-mode (CM) noise compared [12][13][14][15][16][17]. But, due to the totempole structure of QB1 and QB2, a reverse recovery current of QB1 flows to QB2 when QB1 is turned on in the positive cycle, which causes large switching loss at QB2 [18][19][20]. ...
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A totem-pole bridgeless boost converter is one of the most promising topologies for the power factor correction (PFC) stage in high-power applications due to its high efficiency and small number of components. However, due to the totem-pole structure of the field-effect transistor (FET), very high switching loss occurs via the reverse recovery current of the body diode. To solve these problems, critical mode (CRM) control is a good solution to achieve the valley switching technique. With valley switching of CRM control, the switching loss decreases drastically with decreasing turn-on voltage. But, although the CRM control enables valley switching, it is hard to make an exact valley switching control with general zero-voltage detection circuits. In addition, when a frequency limitation scheme is applied to prevent a very high frequency, the switch can operate with hard switching at the boundary of the frequency limitation. Furthermore, the CRM boost PFC has a low PF and high total harmonic distortion (THD) under light-load conditions due to the large negative current resulting from resonance between the inductor and parasitic capacitance. It becomes worse at near-zero input voltage since the resonance current becomes larger near zero-input voltage. Therefore, in this paper, a totem-pole bridgeless boost PFC converter with high efficiency, high PF, and low THD is developed using TMS320F28377 by Texas Instruments. Based on the basic digital structure of the totem-pole bridgeless converter, the proposed controls help with exact valley switching, PF and THD improvement, and frequency limitation. The prototype converter is verified using 90–264 VAC input voltages and 450 V/3.3 kW output specifications.
... As shown in Fig. 1, considering the dc link capacitor (C DC ) of an OBC, the ripple content (V ripple ) is proportional to the load power and its fast Fourier transformation (FFT) contains all even multiple components of the grid frequency, i.e., 2 f g , 4 f g , . . . , 2k f g [19]. As per the conventional current control loop of grid connected OBC, the grid current reference is obtained by multiplying the dc link voltage controller output with the line current (of fundamental frequency f g ), which introduces (2k + 1) f g frequency components in the reference grid current waveform. ...
... Considering the magnitude of predominant second-order effective sinusoidal terms from (16) and equate it to V o in (19), it results in the following equation that relates coefficients in the current equation to the output power and input voltage values (related to block F in Fig. 6): ...
Article
This paper presents a novel active compensation-based harmonic reduction (ACHR) technique in order to mitigate the existing third harmonic component in the input current of the power factor corrector (PFC) circuit in electric vehicle (EV) charging systems. Traditional PFC control scheme includes an outer voltage loop to control the output DC voltage and an inner current loop to ensure that the grid current is sinusoidal. The work shows how third and other high-order harmonic components are created while the signal is transmitting through the voltage control loop, and then an analytical model is developed to calculate the dominant third harmonic magnitude according to the circuit specifications and control parameters. The ACHR approach takes advantage of multi-level filter design to prevent the presence of high-order odd harmonics in addition to mitigating the existing third harmonic component created by the voltage control loop before it is passed through the current control loop. ACHR is designed optimally, and its performance is analyzed in detail to have a robust and stable closed loop system while keeping the characteristics of fundamental harmonic. A totem-pole boost PFC proof-of-concept is built to verify the proposed ACHR technique. The results show that the third harmonic magnitude is reduced from 244 mA in conventional control scheme to 130 mA in proposed ACHR technique. Moreover, total harmonic distortion (THD) in input current is decreased from 4.88% to 4.03%.
... On the basis of average current control, an improved double feedforward control including input and load feedforward was proposed in [14] to optimize the dynamic response of the system, and the peak voltage prediction was used to further improve the performance of the control. A real-time load prediction voltage loop output was proposed, and then the duty cycle was calculated directly from the voltage loop output in [15]. An adaptive constant power control method, adaptive constant power angle operation, has been proposed to achieve efficiency control under light load, while still meeting the output voltage requirements [16]. ...
... The first-order Pade approximation of Equation (5) is used to synthesize a delay system to eliminate the negative modulation, as shown in Equation (15). ...
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In order to improve the charging speed and reduce the occupied volume of an electric vehicle charger, a single-phase boost power factor corrector (PFC) system with cascade CHB (cascaded H-bridge) topology was adopted. Due to the periodic fluctuation of single-phase AC input, there is a large double power frequency ripple component in the output voltage of an AC-DC converter. When capacitor voltage is used as output for feedback control, the control system has the characteristics of a non-minimum phase system. In light of these factors that affect the dynamic stability of the system, a control method is proposed to improve the dynamic characteristics of the system without affecting its steady-state performance. The predictive PI control strategy was adopted to predict the error input signal of the lag process to attenuate the jitter in the control system and improve the dynamic performance and anti-interference of the system. Finally, the feasibility of the scheme was verified by experiments.
... Because of using the non-PWM sliding mode controller, the switching frequency is variable. A cascade buck and boost are applied in [13] in which different duty cycles with variable phase shift structures are considered. The efficiency and power factor are increased. ...
... By considering an additional integral variable at the sliding surface, the ISMC controller's steady-state error is improved in this strategy. The sliding surface and the duty cycle equations are presented as (13) and (14), respectively [17]. ...
Article
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An Electric Vehicle Battery Charger (EVBC) faces serious challenges such as continuous charging voltage ripple, charging speed, input voltage level variations, and its ability to adapt to the Battery State of Charge (BSOC). A proper controller has an important role to play in preparing for all mentioned above. A nonlinear controller such as a Sliding Mode Controller (SMC) is eminently suitable for solving these problems. Therefore, this work presents an improved SMC for taking the control of a DC/DC boost converter such as an EVBC. The proposed controller has a more robust structure when exposed to significant variations of input voltage than the other SMCs. Therefore, this allows the application of various power supplies as input voltages in EVBC stations. The EVBC power and battery voltage/capacity in this converter are assumed to be 14 kW and 400V/60Ah, respectively. The simulation results in Matlab Simulink verify the controller’s high performance compared with other SMCs.
... Moreover, it can directly provide the switching signals of power switches by means of hysteresis modulation. Consequently, the dynamic response in closed loop is the fastest possible [19][20][21][22][23][24]. ...
... Mallik et al. [23] implemented an AC/DC converter based on totem-pole topology with a hybrid PI-SMC controller. AC current and DC voltage errors were considered in the sliding surface design. ...
Article
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This paper proposes a new sliding surface for controlling a Semi-Bridgeless Boost Converter (SBBC) which simultaneously performs Power Factor Correction (PFC) and DC bus regulation. The proposed sliding surface is composed of three terms: First, a normalized DC voltage error term controls the DC bus and rejects DC voltage disturbances. In this case, the normalization was performed for increasing system robustness during start-up and large disturbances. Second, an AC current error term implements a PFC scheme and guarantees fast current stabilization during disturbances. Third, an integral of the AC current error term increases stability of the overall system. In addition, an Adaptive Hysteresis Band (AHB) is implemented for keeping the switching frequency constant and reducing the distortion in zero crossings. Previous papers usually include the first and/or the second terms of the proposed sliding surface, and none consider the AHB. To be best of the author’s knowledge, the proposed Sliding Mode Control (SMC) is the first control strategy for SBBCs that does not require a cascade PI or a hybrid PI-Sliding Mode Control (PI-SMC) for simultaneously controlling AC voltage and DC current, which gives the best dynamic behavior removing DC overvoltages and responding fast to DC voltage changes or DC load current perturbations. Several simulations were carried out to compare the performance of the proposed surface with a cascade PI control, a hybrid PI-SMC and the proposed SMC. Furthermore, a stability analysis of the proposed surface in start-up and under large perturbations was performed. Experimental results for PI-SMC and SMC implemented in a SBBC prototype are also presented.
... This design also enhances thermal management, improving system reliability and efficiency [2]. Interleaved bidirectional PFC converters are particularly valuable in EV chargers due to their bidirectional power flow capability, supporting both Grid-to-Vehicle (G2V) and Vehicle-to-Grid (V2G) operations [3]. This feature is crucial for energy storage and smart grid applications, as it allows EVs to function as distributed energy resources [4]. ...
Article
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This paper presents an optimized control strategy for a bidirectional interleaved totem pole Power Factor Correction (PFC) converter, employing a combination of Model Predictive Control (MPC) and a Proportional-Integral (PI) controller. The converter’s mathematical model is used to implement the MPC, which ensures a unit power factor during both Grid-to-Vehicle (G2V) and Vehicle-to-Grid (V2G) operations. Meanwhile, the PI controller regulates the DC-side voltage. It is worth noting that the MPC’s design eliminates the need for a comparator to generate the Pulse Width Modulation (PWM) signal, simplifying the control architecture. The proposed control technique’s effectiveness is validated through various simulation scenarios in both G2V and V2G power transfer modes, demonstrating satisfactory performance. This integrated approach provides a robust solution for efficient energy management and high-quality power conversion in bidirectional PFC converters.
... At an 800 W load power, the sustained state measurements show a power factor > 0.995 and a total harmonic distortion (THD) of 3%. SMC achieves an 80 ms settling period for a 25% step-change in demand power, which is about 200 ms quicker than the traditional PI control [4]. ...
Article
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This work recommends using an electric vehicle (EV) charging station employing a Vienna rectifier (VR) with sliding mode control. The Vienna rectifier is preferred for high-power applications due to its reduced harmonic distortion and improved power factor correction. Sliding mode control is used to regulate the rectifier's output voltage and current, allowing for reliable and efficient charging of EVs. The suggested system is modeled, and the simulation outcomes are presented to demonstrate the value of the recommended approach concerning stability, strength, and unexpected responsiveness. The proposed technology is expected to contribute to developing more dependable and effective EV charging stations.
... Although SMC has been used in many applications, it was rarely applied in the field of EV battery charging. This control method is particularly well-suited for applications characterized by fluctuating system dynamics, such as EV charging Rathore et al. (2020) and unknown loading conditions Mallik et al. (2018). ...
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This paper describes a digital sliding mode control (SMC) technique applied to a three-phase four-wire rectifier operating at a fixed frequency for ultra-fast charging of electric vehicle (EV) battery. The control algorithm employs three decoupled sliding mode controllers to achieve loss-free resistor (LFR) behavior in each phase for power factor correction (PFC). The design of the sliding mode controller is twofold. The first one is to guarantee convergence of the sliding variable to zero. The equivalent control and the discrete-time dynamic model of the rectifier are obtained by imposing sliding-mode regime in discrete-time. The second one is to stabilize the inner-loop under the obtained control law. Theoretically, the resulting inner-loop is stable with a deadbeat behavior in the inner current loop. The results are validated by numerical simulations using on a 350 kW AC-DC rectifier for EV battery ultra-fast charging applications. The numerical simulation results performed on the switched model implemented in PSIM© software are in close agreement with the theoretical analysis.
... However, in peak and valley control, both analog and digital circuits could be required, while in deadbeat control, performance is affected by distorted grid voltage, circuit parameter mismatch, and control delay [22]. Other control methods in the literature include but are not limited to average currentmode control [23,24], pulse train control [23,25], one-cycle control [26,27], synchronous rectifier control (SR) [28], dynamic evolution control [29], sliding mode control [30][31][32][33], feedforward control [34][35][36][37], dual-division-summation control (D-D-∑) [38], fuzzy logic control [39], double degree-of-freedom variable control [40], finite state machine (FSM) [41], critical conduction mode control (CRM) [42,43], phase shifting control [44], adaptive control [45][46][47], and sinusoidal input current discontinuous conduction mode control [48]. ...
Article
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This paper expands a recently proposed peak current-mode (PCM) control method for a power factor correction (PFC) boost converter to include the totem-pole converter and solves the controller’s compatibility problem with the totem-pole converter by proposing three input current sensing methods. Using MATLAB/Simulink 2023b, simulation experiments on a 2 kW totem-pole converter utilizing the PFC PCM controller were carried out to assess the performance of the controller with the proposed sensing methods. The findings indicate that under steady-state conditions, all three proposed sensing methods performed input current shaping successfully and yielded nearly identical THD% of about 4.4% in the input current waveform. However, it is noteworthy that method 2, referred to as the memory method, exhibited a sluggish and less robust transient response in comparison to the swift and resilient responses observed with method 1 and method 3. Additionally, the third proposed method, which involves a single current sensor positioned across the input inductor, emerged as the optimal and cost-effective sensing solution. This method achieved the same desirable attributes of fast and robust control while utilizing only a single current sensor, a notable advantage over method 1, which employs two current sensors.
... Lately, many control strategies have been proposed, there is no single "perfect" controller for interleaved totem pole AC/DC converters, as the best choice of controller will depend on the specific requirements of the system [11]. That being said, some advanced control techniques that are commonly used for interleaved totem pole AC/DC converters [12,13]. In this present research the control strategy based on the PI controller, by a system consisting of two controllers, an outer-loop DC voltage controller and an inner-loop current controller to ensure the PFC [6,14]. ...
Chapter
This article introduces the modeling and control design of an Interleaved Totem Pole (ITP) Power Factor Correction (PFC) AC/DC converter intended for use in the context of wireless power transfer (WPT) chargers designed for electric vehicles (EVs),based on SIC MOSFET.This converter is employed at 85 kHz in CCM. The main objectives of this research are system modeling, design of control strategies to ensure the global stability, equal sharing between the two parallel legs, and improvement of Total Harmonic Distortion (THD). To achieve these objectives, the system dynamic behavior of the AC/DC interleaved totem pole PFC converter was modeled using mathematical equations and the state space equations. A PI control strategy was then designed to ensure the stability regulation in output voltage and ensuring the PFC power transfer during grid to vehicle G2V modes. The suggested control method underwent testing and validated using MATLAB/Simulink software. The simulation results obtained demonstrating its effectiveness in achieving the desired objectives. The results of this study contribute to the development of advanced control techniques for AC/DC interleaved totem pole PFC converters, improving the reliability and efficiency of power conversion systems.
... In [97], a high-performance and constant switching frequency SMC was proposed for a single-phase inverter that operates with 95.5% efficiency and provides THD less than 1.1% and 1.7% at maximum linear and non-linear loads. To enhance the converter dynamics, guarantee secure regulation of the output voltage under rapid load variations, reduce THD (< 3%), and maintain a PF close to unity (0.995), a complete SMC for single-phase interleaved totem pole PF correction converters in EV on-board charger applications was developed in [98]. In [99], the viability of a novel SMC strategy to control a BDC in a specified powertrain configuration of an EV with an output filter was evaluated. ...
Article
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With the evolution of the smart grid concept, the production of electric vehicles (EVs) is predicted to rise because of environmental concerns, technological advancements, and improvements in EV management. Vehicle‐to‐grid (V2G) is an enabling, realistic, and affordable technology to cope with a large number of EVs, increase energy sustainability, provide economical solutions, satisfy user‐side consumers, and facilitate power flow to the grid. Power electronics (PE) converters, particularly bidirectional power converters, are promising interfaces for V2G infrastructure because they determine the characteristics and functionalities of V2G. Therefore, this study provides an extensive review of the characteristics, technological aspects, and visions of V2G infrastructure. This review helps to identify the current state, most recent developments, and problems related to bidirectional interface topologies and control strategies in V2G infrastructure. It further examines the classification of chargers or dischargers based on numerous factors, including limitations and impacts. Furthermore, the benefits, challenges with possible mitigation solutions, and future outlooks in the implementation of V2G technology are discussed. This review is planned to serve as a reference for existing work in V2G frameworks, PE interfacing topologies, and control strategies, and to also facilitate a guideline for future work that can be implemented to flourish V2G technology.
... • Reduced input and output ripple currents: Interleaved Totem-Pole PFC reduces the input and output ripple currents by interleaving multiple totem-pole converters, which reduces the switching losses in the power switches [86]. • Improved efficiency: Interleaved Totem-Pole PFC improves the efficiency of the power conversion process by reducing the conduction losses and the switching losses in the power switches [87,88]. • Reduced electromagnetic interference (EMI): Interleaved Totem-Pole PFC can reduce EMI by spreading the switching frequency spectrum over a wider range, which reduces the peak EMI levels [89,90]. ...
Article
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Catalyzed by the increasing interest in bi-directional electric vehicles, this paper delves into their significance and the challenges they encounter. Bi-directional electric vehicles not only serve as transportation but also function as essential electricity resources. Central to this energy revolution are On-Board Chargers (OBCs), which are pivotal in converting alternating (AC) energy into direct (DC) energy and vice versa. In this context, we explore the various circuit architectures of OBCs employed in bi-directional electric vehicles. We delve into the intricacies of rectifiers, switching converters, and the application of advanced control and filtering technologies. Our analysis extends to the implications of these circuit architectures on aspects such as voltage regulation capability, energy efficiency, and thermal management. Furthermore, we address the broader significance of these developments in the integration of bidirectional systems, which are driving advances in circuit architectures to better harness the energy flexibility of electric vehicles. We emphasize the critical role of bi-directional electric vehicles in the transition toward a smart and sustainable energy grid. To enhance accessibility for a diverse readership, we will provide concise definitions or explanations for technical terms used throughout the paper, ensuring that our work is approachable even for those who may not be experts in the field.
... In [18], real-time implementation of a power factor correction boost converter with higher-order sliding mode control was introduced (HOSMC). In [19], a simplified sliding mode control for the onboard charger's power factor correction converter was proposed. An adaptive sliding mode control for an AC-DC converter in an electric vehicle system was designed by Rathore et al. [20]. ...
Article
Transformerless power converters are trending in automotive sector as the demand for onboard chargers rises. The high efficiency and leakage current mitigating property of highly efficient and reliable inverter concept (HERIC) converter make it an excellent choice among transformerless topologies. By using appropriate modulation technique, the HERIC converter can transmit bidirectional power. This article presents design of sliding mode controller (SMC) for bidirectional HERIC converter to enhance the tracking performance. The SMC parameters are selected utilizing Harris hawks optimization (HHO) algorithm. During vehicle-to-grid (V2G) operation, sliding mode controller is developed for reactive power regulation of the grid connected HERIC converter and for grid-to-vehicle (G2V) operation, the converter is operated with very low voltage ripples in the DC side. The stability analysis is done by considering model uncertainties to guarantee sinusoidal grid current, low THD, and unity power factor even in the presence of grid disturbances and parametric variations. The Typhoon Hardware in the Loop (HIL) 402 device is used to execute the real-time testing. The results confirmed the efficacy and robustness of the designed controller under different scenarios for both modes of operation.
... Moreover, the CV mode does not cause rapid changes in power consumption. It should be noted that such EV onboard chargers are power electronic systems with built-in regulators [55,56]. For example, a power factor compensation (PFC) [54,57] is commonly built in. ...
Article
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The paper presents the results of the monitoring process of the charging of an electric vehicle battery pack. Battery pack charging with a capacity of 58 kWh was monitored in a single-phase 230 V/50 Hz circuit. The slow charging system used was configured to obtain a current of 10 A. During monitoring, the focus was on the recognition of the charging, considering the impact of this process on power quality and, consequently, on the reliability of electrical machines. Research results show that the monitored charges are one-, two-, or three-stage processes. The variations in the currents, power, and higher harmonic contents were observed. The effects of such variations depend on the properties of the power grid at the point of connection of the charging system. Knowledge of the variation of the voltages, currents, and active and reactive power allows for the determination of the requirements of the measuring equipment used for charging the monitoring, including the selection of discrimination/averaging time of monitored quantities. The research results also indicate the need for continuous monitoring of the power quality in the power supply circuit of electrical loads, e.g., electrical machines. Continuous monitoring supports the diagnostics of electrical machines and allows the appropriate measures to increase their reliability.
... In order to solve these problems, the application of SMC in the converter is proposed in [11,12]. The SMC is a nonlinear control method based on a large-signal model, with features such as wide stability range, fast dynamic response, robustness, and simplicity. ...
Article
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A CLLC resonant converter’s gain is easily influenced by the operating frequency, and when the operating frequency is adjusted over a wide range, the efficiency of the converter is greatly reduced. Traditional closed-loop control strategies also have disadvantages such as slow dynamic response and vulnerability to load. In this paper, a high-order sliding mode control (SMC) design method is proposed based on the current problems and the characteristics of automotive CLLC resonant converters. A sliding mode surface based on the output voltage characteristics of the CLLC converter includes higher-order differential terms for voltage and current and an error integral term for the output voltage, which reduces the operating frequency range of the converter and improves its dynamic responsiveness, thus increasing its efficiency. In order to verify the accuracy of the algorithm, a simulation model is built in MATLAB to verify the stability of the controller by varying the input voltage and the magnitude of the load and to verify the dynamics by abruptly varying parameters such as load and voltage. Comparing high-order SMC with PID control also shows that high-order SMC is more suitable for automotive converters.
... In the context of EV chargers, several control approaches have been developed by contemporary researchers such as model predictive control (MPC) [8], sliding mode control (SMC) [9,10], active disturbance rejection control (ADRC) [11], backstepping control [12], and LSTM neural network [13]. However, most the robust controllers need the system model be accurately identified. ...
Article
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With the increase in the number of electric vehicles (EVs) and developments in their related charging infrastructures, consumers have still some concerns about some limiting factors in the EV industry such as battery life, charging station availability, electric grid capacity, limited driving range, and slow charging of batteries. Although some solutions are proposed for these limitations, they are not sufficiently efficient and cost-effective. Moreover, charging of EVs on-the-road is still a challenging issue which requires more innovation. This paper proposes a novel battery charger, known as an Emergency EV-to-EV Portable Battery Charger (EPBC), which provides a cost-effective solution for charging EVs on-the-road in emergency mode. The suggested smart charger can charge another EV based on the state of charge (SOC), capacity, and other important technical specifications of batteries in a safe and reliable manner. The smart charger can regulate the output voltage and the injected current to the EV simultaneously. To realize these features, a model free nonlinear integral backstepping control (MF-NIBC) is adopted to regulate the output voltage of the battery charger. By utilizing the actor and critic networks, a deep deterministic policy gradient (DDPG) is adopted to adjust the MF-NIBC controller. Finally, real-time tests based on the OPAL-RT setup are conducted to confirm the applicability and feasibility of the proposed EV-to-EV portable battery charger.
... The interleaving of the converter circuit reduces the stress on the charger as similar and parallel paths are available for both the cycles of input voltages. Different interleaved converters are being presented in [13]- [15] which are having inherent benifits like smaller size of inductor, low ripple percentage in output current but the interleaved connection has no positive impact on the heating problem on input end DBR like boost rectifier (conventional). But it has a negative impact of greater current stresses on switches of power factor enehancement circuit. ...
... Interleaving technique provides parallel paths arrangements because of which the average stress developed due to voltages and current got reduced. Having benefits like low percent of ripple in outcomming current, lower inductor ratings, some charging systems utilizing interleaved converters are filed in [13]- [15]. The charging systems utilizing interleaved converters suffers a greater current stresses on switches of power quality improvement circuit. ...
... The work in [14] introduced real-time implementation of power factor correction boost converter with a higher-order sliding mode control (HOSMC). A simplified sliding mode control for power factor correction converter for the onboard charger was presented in [15]. In [16], an adaptive sliding mode control for ac-dc converter in electric vehicle application was developed. ...
Article
High-performance onboard chargers are needed to proliferate the popularity of electric vehicles considering the charging convenience and flexibility. In this study, a sliding mode controller (SMC) for power converters is presented to enhance the performance of the onboard battery charger. The SMC parameters are selected using the particle swarm optimization (PSO) algorithm. A two-stage charging topology is adopted with independent controllers. The grid side AC–DC converter mitigates the harmonic content in the grid current and smoothens the voltage and current in the dc bus. The bidirectional DC–DC converter at the battery side regulates the charging characteristics of the Li-ion battery with a constant current–constant voltage (CC–CV) profile. The steady-state and dynamic behavior of the charging system is presented. Hardware in the loop real-time emulator is utilized to confirm the validity of this study. Experiments show that optimization-based SMC contributes to the overall dynamic performance of the onboard battery charger.
... Ding et al. [19] constructed a second-order sliding mode control law for non-linear constrained systems by using saturation technique and back stepping-like method. Mallik et al. [20] proposed a comprehensive sliding mode control loop design for single-phase interleaved totem-pole power factor correction converters in EV on-board charger applications. Han et al. [21] proposed a special type of sliding mode controller which used a non-linear characteristic of the tire for hybrid four-wheel-drive vehicles. ...
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For attenuating the shimmy phenomenon appeared in an electric vehicle (EV) with independent suspension, this study proposes a finite‐time active shimmy stability control method based on an uncertainty estimation observer. Firstly, a four‐degree‐of‐freedoms shimmy model of an EV with independent suspension is constructed. Secondly, in order to deal with the uncertainties in the shimmy model, a finite‐time control method via a non‐linear uncertain disturbance observer is proposed. The direct Lyapunov function method is used to analyse the global stability of the closed‐loop system, and the results show that the system outputs globally converge to zero. Simulation and hardware‐in‐the‐loop simulation test results verify the built shimmy model and show the effectiveness of the designed control method compared with the sliding mode control method.
... 11 The SMC of a cascaded boost converter for a "fuel cell"-based energy generation system is introduced in Mallik and Khaligh. 12 Only the output voltage is controlled in this work. A unique SMC method for "interleaved totem pole power factor correction converters" is reported in Tian et al., 13 where the sliding surface consists of two variables. ...
Article
This paper develops a hysteresis band‐based multivariable sliding mode control (SMC) for the double input buck buck–boost fused converter. The considered converter is operated at a controlled output voltage, while supplied from two different levels of input voltages from two different sources. The proposed control is to ensure the faster time of responses during the variation in the dual references, the output voltage, and low‐voltage source current, simultaneously. The controller is developed by considering these two controlled variables, which are directly dependent on each other. This multivariable SMC is shown to perform successfully to maintain the controlled variables at their desired values despite the variation in the input voltage sources and also during perturbation in the load impedance. The stability analysis for the closed‐loop system is established with the Lyapunov method, which confirms that both of the controlled variables reach the desired stable band at the steady state. The control is implemented in the simulation environment for different operating conditions. A laboratory prototype is developed to implement the multivariable SMC. The experimental results successfully validate their simulated counterparts.
Article
This paper deals with the control problem of a single‐phase bidirectional alternating current/direct current (AC/DC) totem‐pole power factor correction (PFC) converter intended to be used in wireless power transfer (WPT) chargers for electric vehicles (EVs). The converter is operating as a bridgeless boost rectifier with the PFC functionality during grid to vehicle (G2V) mode and as a PFC inverter during vehicle to grid (V2G) mode. Firstly, the operating principle is presented. Secondly, an overall mathematical model governing all the operating modes of the converter is elaborated. Thirdly, due to the nonlinearity of the studied system, a nonlinear controller–based Lyapunov technique is designed to achieve the following control objectives: (i) unity power factor (UPF) during both power transfer modes G2V and V2G, (ii) regulation of the DC‐link voltage, and (iii) asymptotic stability of the closed‐loop system. Further, as the developed control law requires the measurement of all voltages and currents, an adaptive observer–based Kalman‐like technique is designed to estimate all the required signals and parameters. The performances of the proposed output feedback control technique are validated through several simulation scenarios showing that all control objectives are achieved. It should be noted that the use of the Kalman observer reduces the complexity of the systems as it requires only two measurements (grid voltage and current) making it an advantageous solution over existing solutions where three measurements are generally used. Furthermore, due to the low‐pass filtering behavior of the observer and its susceptibility to estimate the converter's parameters, the robustness of the controller and its insensitivity to the parameter uncertainties are greatly improved.
Article
The most common factors influencing performance of on-board EV chargers are grid voltage and a diverse loading pattern. Furthermore, the proportion of ripples in charging current affects charger and battery health. To overcome these concerns, a model predictive (MP) hybrid dual phase shift modulation (hy-DPSM) approach is developed. It arrives with both unidirectional and bidirectional conduction angle control. Here, cost functions emerge from the refined phase shift (PS) parameter expressions. This is intended to lower peak current stress while retaining in zero-voltage switching (ZVS) region. This results in a secured flat efficiency profile with significant reduction in current ripples throughout a large battery voltage and loading range (maximum to cut-off value). Additionally, a modified per-filtering stage is proposed to safeguard active front end rectifier from grid voltage uncertainties. It is accomplished by integrating a DC offset rejection loop into a conventional second order sequence filter (SOSF). This provides combined immunity to the presence of lower-order harmonics and DC offset in sensed and conditioned grid voltage. In this regard, a 3.3kW hardware prototype is designed in the laboratory to validate the proposed control over numerous charging circumstances.
Conference Paper
The growing demand for high power-density power factor corrector (PFC) solutions for compact adaptors, electric vehicle chargers, light-emitting diode (LED) drivers, etc, necessitates high-performance energy-efficient control to achieve ultra-fast load transient with reduced output capacitor size. In this paper, a trajectory-based controller tuning approach is proposed in a boost PFC converter under digital constant on-time average current mode control (CMC) with normalized load current feedforward, which can achieve near-time-optimal recovery with reduced voltage undershoot/overshoot. Also, a CCM-DCM (continuous \& discontinuous conduction mode) boundary detection technique is incorporated, which offers a natural transition with reduced switching/driving losses. Structural stability analysis is carried out using a discrete-time modeling framework, and the effect of parameter variations is discussed. The effectiveness of the proposed control technique and the performance improvement are demonstrated using simulation results.
Article
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In this paper, a high-efficiency and high-density 2.5 kW four-level interleaved flying capacitor multilevel (FCML) totem-pole bridgeless power-factor-correction (PFC) rectifier with 200 V GaN devices is analyzed, designed, and tested. This 2.5 kW four-level continuous conduction mode (CCM) GaN totem pole PFC operates with three times inductor current ripple frequency than that of the switching frequency which significantly reduces the size of the inductors while also supporting switching loss reduction. This article compares the loss of the two-level CCM GaN totem-pole PFC, four-level non-interleaved FCML PFC and interleaved four-level FCML PFC with the same ripple frequency (300 kHz) and shows that the interleaved four-level CCM GaN PFC has much less device loss. In addition, this article discusses the detailed EMI spectrum analysis and derivation of the mathematical model for determining the attenuation requirement of the four-level interleaved FCML PFC converter followed by volumetric co-optimization of AC-side passives i.e., the boost inductor and differential mode (DM) EMI filter. A 2.5 kW four-level interleaved FCML GaN totem-pole PFC prototype with an optimized 94 kHz switching frequency is developed and tested in this article. The converter exhibits a peak efficiency of 99.14% with system power density reaching 89.47 W/inch 3 .
Article
This article proposes a hybrid control strategy for a single-stage interleaved totem-pole LLC ac–dc converter. Because the totem-pole power factor correction front cell provides bidirectional inductor current, this converter is restricted by operating in continuous conduction mode or critical conduction mode. The traditional control strategy shows a variable duty cycle of the resonant tank voltage to the instantaneous ac input voltage. Therefore, the line-frequency variation from the ac input-end will be easily interfaced with the load and bring a large fluctuation of output voltage. To tackle this issue, this article proposed a novel control strategy that utilizes pulsewidth modulation (PWM) to shape the input current, and pulse frequency modulation to regulate the output voltage. As a positive consequence, the large output voltage ripple brought by the variation of duty cycle for traditional PWM-based control is therefore effectively compensated by the variation of switching frequency, and the power decoupling between the ac pulse input power and constant dc output power is achieved. The numerical-based calculation method is utilized to develop the time-domain analysis of the converter, and a 500 W/150 V experimental prototype has been built to verify the proposed control strategy and theoretical analysis.
Article
This paper proposes a non‐fragile control approach for a non‐isolated two‐switch buck‐boost converter used as an on‐board charger for electric vehicles. The control scheme is based on a cascaded two‐loop configuration with non‐fragile Proportional Integral controllers in the inner current and the outer voltage loop. The control approach is based on designing a control law that can stabilize the closed‐loop system subject to uncertainties in the controller parameters while satisfying the H ∞ norm bound constraint on disturbance attenuation. The proposed control technique helps to deal with inevitable uncertainties during the implementation of any control scheme. The proposed control technique is compared with the conventional approach and validated through experimental results. The experimental results are obtained from a 1‐kW laboratory prototype of a TSBB converter with an output voltage range of 150–400 V. The results demonstrate that the proposed approach effectively achieves good robustness against controller parameter variations and disturbances under various operating conditions.
Article
This paper proposes a fast-response sliding mode controller (SMC) for a semi-bridgeless boost converter under large and quick load fluctuations to ensure tight output voltage regulation and unity power factor correction (PFC) at the line side. In this sense, a novel approach for estimating the reference current profile is presented focusing on the real-time phasor estimation via the O-splines of the discrete-time Taylor-Fourier transform (DTTFT). This method allows for improving the computational efficiency and dynamic performance of the estimations of amplitude, frequency and phase of the network voltage used for the generation of the reference current profile. Several aspects of the controller design are discussed, including the choice of the sliding surface, the existence and stability conditions, and the implementation of an adaptive hysteresis band to fix the switching frequency and reduce zero-crossing distortion. Experimental results of a GaN-based prototype validate the theoretical predictions, exhibiting a PF close to 1 and a total harmonic distortion lower than 3.2% in presence of load changes of up to 50% and changes in the output voltage set point. Several comprehensive experimental comparisons between the proposed framework and the most widely used methods recently reported in the literature are accomplished in terms of transitory and steady-state responses. The robustness of the proposed control approach is experimentally demonstrated under sag conditions and a wide operating range of the input voltage.
Article
This paper analyzes and develops a generalized harmonic approximation (GHA) based small-signal modeling approach, thus incorporating the effect of all the higher order harmonic components present in the system. Adhering to the plant response extracted from the small-signal model, a comprehensive sliding mode control (SMC) based closed loop controller is employed, with thoroughly laid constraints pertaining to the dynamic response of the system, thus ensuring faster transient response and better stability under various operating conditions. An all-GaN based 700W, high power density (6.2 W/cm 3 ) experimental proof-of-concept was built for a conversion from a variable input bus voltage (380-420V) to 12V output at a resonant frequency of 2MHz. The results portrayed a steady state peak efficiency of 95.65%, with an improvement of 2.2% over the state-of-the-art (SOA) operable at MHz frequency. Further, comparison of the dynamic response of the proposed control scheme with the conventional FHA-derived SMC controller for two load changes (10% -90% load step up and 90% -10% load step down) portrayed a 62.9% reduction in settling time and a 44.1% reduction in over/undershoot.
Conference Paper
The Totem-Pole Power Factor Correction (TP-PFC) boost converter is gaining popularity due to its bridgeless topology for rectification purpose. The performance of such converter is affected by numerous factors as reported in the literature. In this work, a new control strategy for the improved performance of the TP-PFC boost converter is proposed with a focus on the following issues. The occurrence of current spike at the zero-crossing of input current is eliminated by introducing a dead-zone. The mixed conduction mode operation of the TP-PFC is avoided at light load conditions using a variable switching frequency scheme, which also improves the THD. Further, the response of the slow DC voltage control loop affects the dynamic response of the converter. The occurrence of a transient condition is detected in this work, and the voltage controller parameters are modified to speed up the voltage response. Thus, a unified controller combining all the above aspects has been developed, and the working of the proposed control strategy is verified through extensive simulation. The improved performance is also validated against that of the conventional control strategy.
Article
This paper discusses the simulation and experimental validation of a curative solution, called power factor correction (PFC), intended to improve the power quality of the single-phase AC/DC converter. A modern control law combined between two methods which are the fuzzy logic theory and the predictive technique is proposed in this research work. The first is reserved to guarantee an intelligent regulation of the DC output voltage while the second aims to the intuitive power switch governance of the boost chopper constituting the PFC. The adopted solution ensures the delivery of a source current of sinusoidal shape, respecting the imposed international standards and the operation of the treated system under a power factor very close to unity. The effectiveness and practical use of the intelligent intuitive PFC control have been experimentally proven using the dSPACE 1104 card for different operating conditions, resulting from the variation of the load and the reference output voltage. The practical results in terms of power quality identified by a total harmonic distortion of the source current of 2.8% and a power factor of 0.995 respect the international standard IEEE 519-2014. Also, they are very convincing compared to those existing and recently published in the literature.
Article
Conventionally, the benchmark proportional-integral control method is implemented to realize power factor correction and output voltage regulation of single-phase ac/dc converters. However, the performance is deteriorated due to the influence of uncertainties and disturbances, e.g., periodic input voltage and load variation. Concerning this problem, this article proposes a model-free control (MFC) strategy of single-phase ac/dc converters. The MFC principle is revisited and a frequency response analysis is presented for the algebraic estimators of uncertainties and disturbances. Consequently, the closed-loop performance of MFC systems is allowed to be analyzed in frequency domain via classical linear control theory. Based on the theoretical results, the model-free current and voltage control systems are synthesized in detail to achieve control objectives of the converter. Simulation results demonstrate the performance of MFC systems in reference tracking and disturbance rejection. The feasibility and validity of the presented MFC strategy for single-phase boost ac/dc converters is also confirmed experimentally as compared to the benchmark scheme.
Article
On-board charger (OBC) is key part of electric vehicles. Limited to space and weight, design objectives of OBC are high power-density and high efficiency. Two-stage circuit is commonly used for 3.3 kW OBC, interleaved power factor correction (ILPFC) is utilized for power factor correction and DC bus voltage regulation, LLC resonant converter is utilized for voltage and power regulations. In this paper, the relationships between the internal parameters and efficiency of ILPFC are studied by discrete iterative method, and the internal parameters are optimized to improve ILPFC`s efficiency. Meanwhile, the relationships between the resonant parameters and efficiency of LLC converter are also studied by fundamental harmonic approximation method to optimize the efficiency in wide charging voltage. A 3.3 kW OBC prototype is developed to verify the effectiveness and correctness of the optimal method, the power factor and total harmonic distortion at full-load state are about 99.99% and 2.98% with the charging voltage ranging from 230 to 430 V, respectively.
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This special issue contributes theoretical and practical advances to the state-of-the-art field at the crossroads of power electronics and control systems. The seven included papers cover particular applications requiring either DC–DC, DC–AC or AC–DC conversion stages.
Article
This paper presents a sigma-modified adaptive control algorithm to enhance the charging profile in a multi-objective electric vehicle (EV) charging installation. The present algorithm takes care of multiple parametric uncertainties and grid non-idealities to provide an instantaneous control updation in order to achieve well-regulated charging dynamics. With the support of renewable energy and battery energy storage (BES), the present algorithm also ensures an uninterrupted charging profile with controller robustness and stability for bi-directional EV charging. The sigma-mod adaptive controller provides an iterative error convergence at each clock interval of supply voltage dynamics to guarantee improved power quality operation in presence of grid distortions. To further improve the reliability of EV charging opportunities, a solar photovoltaic (PV) array in conjunction with the battery energy storage supports the ancillary services through maximum power point operation. Multivariable sliding mode control and rule-based phase-shift adaptation at different stages of power transformation assure faster convergence, parameter uncertainty and controller stability for the bi-directional EV charging operation. A 3.3 kW PV-integrated off-board charging facility is designed and developed as a laboratory prototype to validate the multi-mode charging architecture with minimal grid dependency.
Article
Single-stage three-phase isolated matrix rectifiers (TIMRs) have high efficiency and compact configurations and are very suitable for electric vehicle (EV) chargers. However, external and internal disturbances challenge the robustness and tracking performance of EV chargers, and conventional PI controllers cannot solve the unmodeled dynamics and the uncertainty of model parameters in the system, so other feedback controllers, which have disturbance rejection performance, need to be designed. Therefore, this paper proposes a dual-loop control strategy based on active disturbance rejection control (ADRC) to guarantee high-speed dynamic response and strong robustness against disturbances. First, the dynamic model of the TIMR is established and divided into two parts to facilitate controller design. Second, the extended state observer is designed to estimate and compensate for the disturbances of the system, and the inner current loop and the outer current loop are designed based on the second-order ADRC. In addition, a simplified parameter-tuning method of the proposed control scheme is presented in detail. Finally, a frequency-domain analysis is given to explain the robust performance of the proposed control scheme. The effectiveness and feasibility of the proposed controller are verified by simulation and experimental results.
Article
This paper presents a double integral sliding mode control (DSMC) and a variable phase-shift algorithm for a bi-directional EV (BEV) charger based on a front-end bridge-less converter. An interleaved phase-shifted bridgeless converter is widely preferred for AC-DC bi-directional power conversion due to its reduced switching loss and a significant decrease in passive filter components. However, the converter commutation process during phase-reversal in presence of grid distortion often adds complexity to achieve zero voltage switching. Estimation of grid frequency and closer zero-crossing detection (ZCD) at the point of common coupling (PCC) during abnormal grid conditions are the key challenges for the successive operation of bridgeless converter topology. This paper describes an adaptive grid-frequency identification technique with noise uncertainty to identify a closer phase-reversal occurrence for ZCD. The DSMC, in addition, offers flexibility towards parametric variation with a gain adaptive control. A modification in the phase-shift algorithm of the DC-DC power converter is also explained with the inclusion of charging dynamics of battery operation. The DSMC and phase-shift control with improved ZCD, are implemented in the Opal-RT platform to verify the charging performance with severe distorted grid conditions. A laboratory prototype for a 3.3kW EV charger is also developed to validate the controller implementation for BEV charging operation.
Article
This paper proposes a modification in the interleaved negative output elementary Luo converter to act as front‐end power factor correction converter for on‐board electric vehicle (EV) charger. The proposed converter is simple in design and offers non‐inverted DC link output voltage. The proposed converter has the advantages—high efficiency, near unity power factor, low AC source current distortion resulting in power quality enhancement, better DC load voltage regulation, and reduced component count. Due to interleaved configuration, rating of circuit components gets greatly reduced. Also, minimum numbers of circuit components pave the way for simple system design of on‐board EV charger. The steady‐state performance of the designed 100‐W, 48‐V converter with closed‐loop controller is analyzed under universal input voltage variation and wide range of load power variation. The converter is designed to provide stable operation when subjected to sudden disturbance in load power/supply voltage. The simulation analysis is done using MATLAB/Simulink platform. A prototype of 48‐V, 100‐W converter is built and tested. Results obtained reveal the superior performance of proposed converter under steady‐state and transient conditions. The closed‐loop control of single‐phase interleaved Luo front‐end power factor correction converter providing non‐inverted output voltage for on‐board EV charger is presented. The ultimate aim is to design simple system for providing better load voltage regulation along with reduced source current harmonics at unity power factor for wide range of load power/supply voltage.
Article
Purpose With the advancement of technology, size, cost, and losses of the switched mode power supply (SMPS) have been decreasing. However, due to the high frequency switching, design of magnetic drives and isolation circuits are becoming a crucial factor in SMPS. This paper presents design criteria, procedure and implementation of AC-DC half bridge (HB) converter with lower cost, smaller size and lower voltage stress on the power switch. Design/Methodology/approach The HB converter is designed in a symmetrical mode with a series coupling capacitor. Isolated power supplies are used for the converter and control circuit. Further, a transformer based isolated gate driver is used to drive both MOSFETs. The control IC works in voltage control mode to regulate voltage by controlling the duty cycle of the MOSFETs. Findings Control characteristics and performance of the HB converter is simulated using the MATLAB software and prototype of 170 W HB converter is built to validate the analytical results under variable load current and source voltage. The power quality and variation of load voltage at 2 A, 5 A, 7 A are reported. Originality/value This paper presents the design of a low-cost HB converter in a symmetrical mode which saves the additional cost of symmetric correction circuit normally required in asymmetrical mode design. This paper also focuses on the selection of primary and secondary side switch, series coupling capacitor, commuting diode, isolated drive and charge equalizer resistor.
Article
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In this paper, an optimal time-varying compensation method with zero eigenvalue is first put forward for peak current-controlled power factor correction (PFC) boost converter, which can eliminate the fast-scale instability without zero current dead zone and achieve unity power factor. First, a time-varying mathematic model of a peak current-controlled PFC boost converter under continuous conduction mode is established. Then, based on the theoretical and experimental analyses of the traditional ramp compensation, a time-varying dynamic compensation model and method are presented to obtain zero eigenvalue during the whole line cycle. Therefore, the PFC boost converter occupies the strongest stability control during each switching cycle and can run into stable operation in one switching cycle under any external interference. Finally, the proposed compensation method is verified with experiments. Results show that a unity power factor and the stability in the whole line cycle can be obtained simultaneously.
Conference Paper
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In this paper current sensorless solutions for AC-DC boost converter Power Factor Control (PFC) have been presented. A Passivity-Based Control (PBC) and a Sliding Mode Control (SMC) with input voltage feedforward have been implemented to increase Power Factor (PF) and their performance has been compared. A robust current observer has been adopted in order to eliminate the need for expensive current sensors. The proposed solution has been numerically tested on a powerful software simulation platform.
Article
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In this paper, a new front end ac-dc bridgeless interleaved power factor correction topology is proposed for level II plug-in hybrid electric vehicle (PHEV) battery charging. The topology can achieve high efficiency, which is critical for minimizing the charger size, PHEV charging time and the amount and cost of electricity drawn from the utility. In addition, a detailed analytical model for this topology is presented, enabling the calculation of the converter power losses and efficiency. Experimental and simulation results are included for a prototype boost converter converting universal ac input voltage (85-265 V) to 400 V dc output at up to 3.4 kW load. The experimental results demonstrate a power factor greater than 0.99 from 750 W to 3.4 kW, THD less than 5% from half load to full load and a peak efficiency of 98.9% at 70 kHz switching frequency, 265 V input and 1.2 kW load.
Article
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In this paper, a systematic review of bridgeless power factor correction (PFC) boost rectifiers, also called dual boost PFC rectifiers, is presented. Performance comparison between the conventional PFC boost rectifier and a representative member of the bridgeless PFC boost rectifier family is performed. Loss analysis and experimental efficiency evaluation for both CCM and DCM/CCM boundary operations are provided.
Article
This paper proposes a systematic approach to model and optimize an integrated transformer for on-board chargers in electric vehicles. The proposed approach includes a comprehensive transformer loss model with accurate electromagnetic description of leakage inductance and optimization process. The multi-objective optimization using genetic algorithm is presented to optimize the performancespace variables i.e. volume, weight and losses by appropriate selections of design-space parameters i.e. winding specifications and core candidacies. Four sets of integrated transformers are optimally designed and compared in terms of the theoretical analyses; finite element analyses (FEA) and experimental performance. As verification to the proof-ofconcept, the integrated transformers are implemented and tested on a 3.3kW on-board charger prototype. It has been shown that the measured losses agree with the theoretical computation. The peak efficiency of CLLC stage with the optimal selection of transformer reaches 98.2%, achieving efficiency enhancement and temperature improvement in comparison to other feasible candidates.
Article
This paper presents a systematic and comprehensive approach for differential mode (DM) EMI filter design in a three-phase boost-type power factor correction rectifier. Since the DM EMI filter forms a significant portion of the overall filter as well as converter volume, reduction of DM filter component size is kept as a major objective in the filter design process in order to improve the power density. In addition to the objectives of volume optimization and conducted emission attenuation requirement to comply with the EMI standard, the filter design process also ensures a near-unity power factor operation with the optimal set of EMI filter parameters. To accomplish this, the paper analyzes the effect of EMI filter component selection on the overall lower order (1-100 kHz) frequency response, which is important for evaluating the dynamic response and stability. The results from the proposed design approach are validated through simulation, the DM Bode plot, and frequency response of the input current with and without EMI filter. As a proof-of-concept verification, the proposed EMI filter is implemented in a 4 kW three-phase boost-PFC prototype, which demonstrates minimal phase displacement (<5o) of the input current.
Article
This paper proposes a unique integrated and isolated dual-output dc-dc resonant converter, which can interface both HV traction batteries and LV loads. In addition, the proposed topology is bidirectional, capable of delivering power from HV traction batteries to the grid for vehicle-to-grid (V2G) applications. To increase the power density of the converter, the dual-output dc-dc resonant converter combines magnetic components of resonant networks into a single three-winding electromagnetically integrated transformer. The resonant converter uses a half-bridge topology with split capacitors as the resonant network components to further reduce the size of converter. The variable DC-link voltage strategy is utilized to enhance the efficiency over the entire output voltage range. A 3.3-kW converter is designed and developed for validation of various operation modes, including G2V, V2G and HV-to-LV (H2L) charging.
Article
This paper presents a method for efficiency estimation of boost derived continuous conduction mode power factor correction (CCM-PFC) converters for electric vehicle (EV) onboard chargers (OBC). The proposed methodology incorporates converter non-idealities, especially caused by magnetic components. The value of the magnetizing inductance in an inductor or transformer core does not remain constant over variable current levels, which cause non-uniform power losses at different current levels. The method proposed in this paper considers a time variant inductance over various current levels and accordingly, establishes a dynamic model of loss estimation. As a proof-of-concept verification, the approach is applied to three different PFC topologies for EV applications and the estimated conversion efficiencies exhibit good agreement with experimentally obtained efficiency values over a wide range of load power from 400W to 4.6 kW. The deviation of the predicted efficiency from the experimental data is considerably lower in comparison with the existing estimation methods with fixed inductance assumption.
Article
This paper presents a methodology to control a two-staged AC/DC converter, which is a cascade combination of a three-phase AC-DC boost power factor correction (PFC) rectifier and a phase-shifted full bridge (PSFB) DC/DC converter. This manuscript explains the issues of instability and losing unity power factor operation i.e. high reactive power transfer with conventional PI compensator due to the sensitive variation of output impedance of the PFC stage at different loads. In our work, this instability issue is resolved by the proposed state-feedback control methodology, which shows that there exists a load-insensitive range of controller parameters, providing unity PFC. As an additional benefit of this control, total number of sensors are reduced by three (an input phase current, a DC/DC primary current and an output DC voltage), in comparison to the conventional PI-based control. This reduction is achieved by introducing two augmented state variables followed by their reduced state observer design. A 6kW laboratory prototype of the integrated three-phase PFC and PSFB DC/DC is developed and designed to validate the proposed control algorithm. The experimental results show a conversion efficiency of 95.4% at full load, input total harmonic distortion (THD) of 4.1%, power factor of 0.998 and output voltage ripple of ±1%.
Article
This paper deals with the switching regulation of boost power factor correction (PFC) converter under large and quick load fluctuation to ensure tight output voltage regulation and unity PF (UPF) at line side. In this sense, the sliding-mode control (SMC) technique based on current-controlled manifold is proposed. Input current distortion is limited even during light loading condition. In addition, the dead-zone issue related to light load near to the crossover of input current is resolved in this paper. To execute the proposed SMC algorithm, equivalent control approach is used for the selection of sliding coefficients, ensuring the system stability. The control operation manipulates both inner SM current controller to frame input current and an outer PI controller to maintain desired regulated output voltage. For experimental validation, a 500-W, 390 V/dc boost PFC prototype, controlled by dSPACE 1104 signal processor is framed. The presented simulation and experimental results infer that the proposed converter controller offers UPF, tight output voltage regulation, and percentage total harmonic distortion standard even under fluctuating load behavior. In this paper, the performance of the proposed control scheme is experimentally verified with different load behaviors and external references, which explains the robustness and effectiveness of the proposed system.
Article
In this paper, the single-loop current sensorless controls (SLCSC) for single-phase boost-type switching-mode-rectifiers (SMRs) are developed and digitally implemented in DSP-based system. Compared to the conventional multi-loop control with one inner current loop and one outer voltage loop, there is only one voltage loop in the proposed SLCSCs where its output is used to shift the nominal duty ratio pattern generated from the sensed input and output voltage. Because of no current loop, the efforts of sampling and tracking inductor current are unnecessary. It implies that the proposed SLCSCs are simple and very adaptable to the implementation with mixed-signal integrated circuits. It is also noted that the proposed SLCSCs are operated at continuous-current- mode (CCM). In this paper, first, the effects of shifting nominal duty ratio pattern on the input current waveform are analyzed and modeled with considering the inductor resistance and conduction voltages. It shows that the aligned current waveform can be inherently generated by the nominal duty ratio pattern and the current amplitude is roughly proportional to the shifting phase of nominal duty ratio pattern. Then, a voltage controller is included to regulate the dc output voltage by tuning this controllable phase. Finally, some simulated and experimental results have been given to demonstrate the performances of the proposed SLCSCs.
Conference Paper
In this paper, the variable-bandwidth hysteresis-modulation sliding-mode (VB-HM-SM) method is applied for a single-stage single-switch isolated power-factor-correction (PFC) regulator. In the regulator, the dc-dc stage works in CCM and is regulated by PWM, while the ac-dc boost stage works in DCM and is regulated by PFM. However, both PWM and PFM are realized by a sliding mode (SM) controller, and thus, unity power factor and fast output voltage regulation can be simultaneously achieved. Various aspects of the design, including the associated practical problems and the proposed solutions are detailed. A simple and easy-to-follow design procedure is also described. Simulation results are presented to illustrate the design procedure.
Conference Paper
The digital implementation of a sliding-mode based control for a dual-boost rectifier with power factor correction (PFC) is presented in this paper. The proposed scheme has a current controller tracking a pure sine-wave reference, whose amplitude is a function of the output voltage error affected by proportional and integral terms. Thus, both power factor correction and output voltage regulation are simultaneously achieved. The performance of the overall converter was verified using MATLAB-based simulations and experimental results in a 120 W prototype, obtaining an unitary power factor and a total harmonic distortion (THD) below 3%.
Conference Paper
This paper introduces an input impedance and current (IIC) feedforward control with leading-lagging phase admittance cancellation (LLPAC) for ac-dc boost converter applications requiring higher efficiency and higher power quality. Whereas the conventional voltage feedforward method guarantees its ideal input admittance by generating average switch voltage effectively under well-regulated current compensator, the proposed IIC method contains an extra compensation term reducing the effects of external input parameters as well as an average switch voltage, resulting in improving input power quality in low switching frequency and high line frequency applications. Consequently, the proposed method allows obtaining more constant input admittance in both regions of leading and lagging-phase. In order to compare three different control approaches, the small-signal input admittances of the ac/dc boost converters are modeled and analyzed. A MATLAB/Simulink model and a 1.2kW dual boost PFC prototype board controlled by a digital signal processor are implemented to demonstrate the effectiveness of the proposed IIC feedforward control.
Article
In this paper, the efficiency and power factor performance of improved power factor correction (PFC) topologies suitable for a high density and efficient design are compared. Several topologies, including a conventional average current mode control boost PFC, an interleaved boost PFC, a back-to-back bridgeless boost PFC, and a semi-bridgeless boost PFC, are assessed through loss analysis and simulation using whole height 1 U and 2 kW class prototypes. Based on this, an optimal topology is selected for which an additional comparative analysis involving input line measure improvement control is conducted. The results of these experiments can be adapted for use in the circuit selection of high-performance converters with power factor improvement circuits.
Article
A simple control strategy to reduce the total harmonic distortion in single-stage high-order power factor correction AC-DC circuits is presented. A variable hysteresis window is used to improve the system performance near the zero crossing of the input current by increasing the switching frequency near this region.
Article
In this paper, a phase-shifted semi-bridgeless boost power-factor-corrected (PFC) converter is proposed to simplify the current-sensing technique for the semi-bridgeless PFC converter. The converter features high efficiency at light loads and low ac input lines, which is critical to minimize the charger size, charging time, and amount and cost of electricity drawn from the utility. The converter is applicable for automotive levels I and II but is ideally suited for level-I residential charging applications. A detailed converter description and steady-state operation analysis of this converter is presented. Experimental results of a prototype boost converter, converting the universal ac input voltage to 400 V dc at 3.4 kW, are given, and the results are compared with an interleaved boost converter to verify the proof of concept and the reported analytical work.
Conference Paper
In this paper, a systematic review of bridgeless PFC boost rectifiers, also called dual boost PFC rectifiers, is presented. Performance comparison between the conventional PFC boost rectifier and a representative member of the bridgeless PFC boost rectifier family is performed. Design considerations and experimental results in both CCM and DCM/CCM boundary operations are provided.
Article
In this paper, the first single-loop current sensorless control (SLCSC) in continuous current mode (CCM) for single-phase boost-type switching-mode rectifiers (SMRs) is developed and digitally implemented in a DSP-based system. Compared to the conventional multiloop control with one inner current loop and one outer voltage loop, there is only one voltage loop in the proposed SLCSC, where the voltage loop's output is used to shift the nominal duty ratio pattern generated from the sensed input and output voltages. Because of no current loop, the efforts of sampling and tracking inductor current can be saved. It implies that the proposed SLCSC is simple and very adaptable to the implementation with mixed-signal ICs. First, the effects of shifting nominal duty ratio pattern on the input current waveform are analyzed and modeled by considering the inductor resistance and conduction voltages. The result of analysis shows that the pure sinusoidal current can be inherently generated by the nominal duty ratio pattern where the current amplitude is roughly proportional to the controllable phase of nominal duty ratio pattern. Then, a voltage controller is included to regulate the DC output voltage by tuning this controllable phase. Finally, some simulated and experimental results have been given to demonstrate the performance of the proposed SLCSC.
Conference Paper
Power-factor-correction (PFC) boost converter is the common choice for a pure sinusoidal current with a near unity power factor. The dynamics of PFC converter can be periodic with line frequency or switching frequency. This paper describes low-frequency instability, which has the practical effect on power factor values. The converter has been controlled using a conventional average-current-mode control to operate at continuous-conduction-mode (CCM). Computer simulations based on nonlinear analysis are performed to study the system stability under the variation of some chosen parameters such as load, output capacitor and feedback gain. Also, the regions of instability phenomena of the PFC converter are delimited, which is of practical interest for engineering design. The nonlinear analysis is constructed mainly from the state-space equation averaged over the switching frequency only. Based on this analysis, new two-dimensional bifurcation maps are provided to give some general outstanding about stability conditions and to identify the stable regions in the parameters space. Moreover, these maps provide an indication about the PFC converter dynamics such as its power factor values and load regulations. Beside, a prototype design of the PFC circuit is introduced to detect these instability experimentally and confirm the simulated result. Results show a good agreement between the numerical analysis and experiment.
Conference Paper
This paper reviews the instability problem and the analysis methods for the cascaded power electronics system. Based on the review, a compromised method is proposed. Due to the fact that the instability is caused by impedance interaction, analysis and improvement approaches for the input impedances of both PFC converters and DC/DC converters are presented in this paper. Simulation results verify the theoretical analysis.
Conference Paper
A new AC-to-DC converter is described which improves the power factor of the AC input line. The converter is composed of a forward converter and a flyback-derived voltage-commutated circuit. When the switching transistor is on, the induced voltage across the transformer is applied to the inductor of the feedback circuit, and energy is stored. When the input voltage is high, the voltage across the capacitor of the feedback circuit does not commutate to the input, while when the input voltage is low, the voltage across the capacitor of the feedback circuit is commutated to the input side capacitor. Therefore, the time duration of the input current is longer than the conventional one, and the power factor is improved. Analysis of the converter circuit and experimental results are presented.< >
Article
We investigate the bifurcations that occur when a power-electronic converter moves from continuous conduction mode (CCM) to discontinuous conduction mode (DCM) due to on-load parameter fluctuations. We derive the discrete map and show that the map is piecewise smooth, with the special property that on one side of the borderline, the determinant is less than -1, and on the other side the determinant is zero. We develop the theory of border collision bifurcations for this special condition, and explain the bifurcations observed at the CCM-DCM transition in the current mode controlled boost converter in the light of this theory.