Yongheng Yang

Zhejiang University | ZJU · Department of Electrical Engineering

In distributed power generation systems, the inherent resonance phenomena of LCL-filtered grid-connected inverter is one of the major challenges faced by the integration of renewable energy resources with the electric power grid. In this context, the capacitor current based multi-loop active damping method is employed due to lossless resonance damp...

Partial shading and other non-ideal conditions cause electrical mismatches that reduce the output power generated by a photovoltaic (PV) system. It affects the overall performance and efficiency of PV systems. Therefore, a model is developed in MATLAB, which analyses the performance of the PV systems under real irradiance profiles and temperatures...

1500-V Photovoltaic (PV) configuration is the standard design in the solar PV industry. Extending the maximum DC voltage from 1000 V to 1500 V can reduce the installation cost of the entire power plant. However, it may affect the reliability of the corresponding 1500-V PV inverters, due to the increased loading stresses, i.e., voltage stress and th...

Recent energy systems have witnessed a large number of extreme weather events due to the global climate change, resulting in severe damages and economic losses. To address this problem, this paper proposes a multi-stage stochastic programming model for resilient integrated electricity and natural gas distribution systems under typhoon natural disas...

Building photovoltaic (PV) may provide a growing share of electricity for big cities. However, lack of measured radiation data on vertical surface remains a critical problem for building PV deployment. With the development of urbanization and industrialization, high aerosol load is altering the nature of solar radiation in Beijing. Hence, ten in‐pl...

The increasing deployment of power converters has led to a significant reduction in the power system inertia and consequently resulted in frequency stability issues. To improve the robustness of the grid against frequency disturbances, it is becoming more expected in many countries that renewable energy generation, such as wind turbine power system...

Learning methods have been increasingly used in power engineering to perform various tasks. In this paper, a fault selection procedure in double-circuit transmission lines employing different learning methods is accordingly proposed. In the proposed procedure, the discrete Fourier transform (DFT) is used to pre-process raw data from the transmissio...

The use of costly speed sensors challenges the overall system reliability in induction motor drives. Hence, speed-sensorless control techniques are desired in high-performance induction motors, where estimating the motor speed is of importance. Distinctive advantages, e.g., structural and control simplicity and acceptable performance, have pushed t...

Electric vehicles (EVs) have attracted enormous attention in re-cent years due to their potentials in mitigating energy crisis and air pollutions. However, the long battery charging time and lack of sufficient charging infrastructure highly restrict the populari-zation of EVs. In this context, it is promising to establish battery charging and swapp...

In this paper, the dual-active-bridge (DAB) DC-DC converter with phase-shift control is explored extensively, and the optimal performances obtained with different objectives are comparatively analysis in each mode. Firstly, the principle and operating modes of the TPS control are introduced in detail. Secondly, the electrical characteristics of the...

Flexible active power control (FAPC) is becoming mandatory for PV systems, which is to limit/reserve the PV power below certain constraints as commanded, including the power ramp-rate control (PRRC), power limiting control (PLC), and power reserve control (PRC). In practice, energy storage such as batteries can be adopted to reduce the PV energy di...

For N-cells cascaded H-bridge (CHB) inverters based on unipolar double frequency phase-shifted pulse-width modulation (PS-PWM), the output voltage is distorted and its harmonics are difficult to be suppressed under unbalanced conditions (different dc voltages and/or modulation indices). This article proposes a closed-loop harmonic suppression schem...

To enhance the power quality and stability of photovoltaic (PV) systems, energy storage elements such as batteries can be included. Among various structures of PV-battery-hybrid (PVBH) systems, the series configuration attracts much popularity. However, certain operating conditions have not previously been considered for the series PVBH system. For...

This paper proposes two improved cascaded H-bridge (ICHB) multilevel inverters that feature voltage-boosting capability. The conventional H-bridge with a front-end dc-dc boost converter was restructured for single-stage operation. The developed three-level topology not only saves one power switch but also exhibits lower voltage stress across its ca...

The drastically increased integration of renewable energy in the power grid is of significance in the transition to a sustainable energy future. The grid integration of renewables will be continuously enhanced in the future. According to the International Renewable Energy Agency (IRENA), renewable technology is the main pathway to reach zero carbon...

Phase-locked loops (PLLs) and frequency-locked loops (FLLs) are of importance in power and energy applications. Both technologies have been introduced to speed-sensorless-controlled motor drives, and increasing applications of PLLs and FLLs for speed estimation are foreseen. To enable a proper and good design, a thorough review of the PLL-and FLL-b...

Over the past decade, the high penetration of renewable-based distributed generation (DG) units has witnessed a considerable rise in electrical networks. In this context, direct current (DC) microgrids based on DGs are being preferred due to having less complexity for the establishment and control. At the same time, they offer higher efficiency and...

This paper presents a generalized restructured topology for boost, buck-boost and its derived dc/dc converters with rearranging branches to enhance the reliability of the converter. This paper instigates the derivation of state-of-the-art topologies with reduced capacitor voltage stress. Mainly in the restructured topology, the capacitor branch is...

In this letter, an improved model predictive control (MPC) has been proposed for single-phase grid-tied converter with virtual vectors in a reshaped and compacted solution space, while improving ac power quality, without increase of the virtual vectors number. Combining linear solution space reconstruction method, the global optimization solution s...

This paper presents a generalized restructured topology for boost, buck-boost and its derived dc/dc converters with rearranging branches to enhance the reliability of the converter. This paper instigates the derivation of state-of-the-art topologies with reduced capacitor voltage stress. Mainly in the restructured topology, the capacitor branch is...

Transformerless single-phase inverters are preferring in residential grid-connected PV systems when compared to galvanic-isolated ones (i.e., transformer-based inverters). In addition to the special leakage current issue, high efficiency, power quality and reactive power injection are of concern that should be considered in grid-connected applicati...

This letter proposes a method to model the power converter availability for power system adequacy assessment. The proposed method considers wear-out as well as chance failures and calculates an equivalent failure rate accordingly. In this regard, it is shown that neglecting the wear-out failures and the dynamic behavior of adequacy indices can lead...

Internet of Things (IoT) and advanced communication technologies have demonstrated great potential to manage residential energy resources by enabling demand-side management (DSM). Home energy management systems (HEMSs) can automatically control electricity production and usage inside homes using DSM techniques. These HEMSs will wirelessly collect i...

Using a multi-port converter to integrate renewable energy and energy storage into the bipolar dc bus is a desirable solution due to its high efficiency and reliability. In this paper, a series of bipolar output active rectifiers with center-tapped winding are proposed to serve as secondary rectification circuits. Then, a family of isolated four-po...

In this paper, we investigate the management of energy storage control and load scheduling in scenarios considering a grid-connected photovoltaic (PV) system using packetized energy management. The aim is to reduce an average aggregated system cost through the proposed \textit{packetized energy management controller} considering household energy co...

An LLC-DAB bidirectional converter with reduced switch count as a DC-DC transformer (DCX) is proposed in this paper. It can achieve voltage regulation, full load range zero voltage switching (ZVS) for eight main switches and wide load range ZVS for four auxiliary switches, with consideration of the switch junction capacitors under different power d...

An LLC-DAB bidirectional converter with reduced switch count as a DC-DC transformer (DCX) is proposed in this paper. It can achieve voltage regulation, full load range zero voltage switching (ZVS) for eight main switches and wide load range ZVS for four auxiliary switches, with consideration of the switch junction capacitors under different power d...

Hybrid energy storage systems (HESSs) can simultaneously harness the advantages of batteries and supercapacitors (SCs) in various loading situations. Coupled with communication links, cyber-physical HESSs (CPHSs) would be threatened by unexpected cyber attacks that may cause damage to electrical devices and even collapse the entire system. To overc...

Cascaded multilevel inverter produces a step-up output voltage by series-connection of several submodules supplied by isolated dc sources which can be implemented by photovoltaic (PV) sources. The unbalanced power provided by different PV sources may however distort the output voltage. To use a single dc source while retaining the voltage boosting,...

With the presence of speed sensors, challenges, including deteriorated system reliability hut increased system cost, have been imposed on induction motor drives. Hence, speed-sensorless control techniques are required in highperformance induction motor drives. Distinctive advantages, e.g., structural and control simplicity and acceptable performanc...

This paper investigates the potential to enhance the reliability of 1500-V single-stage photovoltaic (PV) inverters with a junction temperature control strategy, where PV inverters can operate either in the maximum power point tracking mode or a junction temperature limit control mode depending on the thermal stress on the inverter power devices. W...

The increasing amount of solar photovoltaic (PV) penetration substitutes a large portion of conventional synchronous power plants. During the peak power production period, it may lead to reduced the rotational inertia and thereby deteriorate inherent inertial response of the power system. It is assumed that the conventional generators mainly provid...

The manuscripts should be submitted through Manuscript Central at https://mc03.manuscriptcentral.com/tpea-cpss. Submissions must be clearly marked “Special Issue on Power Quality Conditioning in Modern Power Grids Integrated Emerging Power Electronic Systems, 2021” on the cover page. The information about manuscript preparation and requirements is...

Digitalization has led to radical changes in the distribution of goods across various sectors. The tendency is to move from traditional buyer-seller markets to subscriptionbased, on-demand "smart" matching platforms enabled by pervasive information and communications technologies (ICTs). The driving force behind this lies in the fact that assets, w...

The unbalanced power losses of the semiconductor switches affect the thermal loading, and thus, the reliability of power converters is challenged. In this paper, the unbalance loss distribution of power devices has been analyzed in a full-bridge (FB) PV inverter, which employs the traditional hybrid unipolar pulse width modulation (UPWM) for reacti...

Voltage boosting three-level inverters may present a monotonically increasing or decreasing voltage gain when enlarging the pulse-width modulation (PWM) ratio. To produce a flexible voltage gain, this paper proposes a novel three-phase three-level PWM inverter by cascading a traditional two-level three-leg (B6) inverter with half-bridges. The propo...

Grid frequency support, e.g., by the virtual inertia control (VIC), of photovoltaic (PV) systems, is more demanded than ever before. To achieve full-range frequency support (i.e., to tackle the under- or over-frequency issues), the power reserve is necessary for PV systems. Accordingly, a power reserve control (PRC) method based on the maximum powe...

A reconfiguration technique using a switched-capacitor (SC)-based voltage equalizer differential power processing (DPP) concept is proposed in this paper for photovoltaic (PV) systems at a cell/subpanel/panel-level. The proposed active diffusion charge redistribution (ADCR) architecture increases the energy yield during mismatch and adds a voltage...

Partial shading affects the energy harvested from photovoltaic (PV) modules, leading to a mismatch in PV systems and causing energy losses. For this purpose, differential power processing (DPP) converters are the emerging power electronic-based topologies used to address the mismatch issues. Normally, PV modules are connected in series and DPP conv...

To enable more wide-scale exploitation of renewable energy sources (RESs), distributed generations (DGs) as in microgrids have gained prominence recently. This study describes the design, modeling, implementation, and operation of a microgrid, in which a standalone hybrid power system has been installed for an education and research laboratory. The...

Starting from the principle of instantaneous power theory, this paper explores various direct power control (DPC) strategies for three-phase two-level pulse-width modulation (PWM) converters. After summarizing the fundamental power formula of PWM rectifiers, the paper studies the operating principle of the conventional table-based approach and its...

Catastrophic faults in photovoltaic (PV) arrays, if not detected timely, will significantly reduce the output power and even cause fire risks. Thus, fast and accurate fault detection and diagnosis techniques are of importance to enhance the efficiency, reliability, and safety of PV systems. However, conventional methods fail to detect faults at low...

If we look at the history of renewable energy sources (RESs), how it all began, and how rapidly they continue to develop, it can be argued that one of the main reasons is due to the rapid improvements in power electronics technology in interfacing the renewable source to the grid [...]

Switched-capacitor-based multilevel inverters for boost-type dc-ac power conversions usually exhibit a trade-off between the switch count and switch-voltage rating, i.e., a reduction of one necessitating an increase of the other. Such a dilemma is well addressed in this paper by proposing a novel single-phase nine-level inverter based on a switched...

This paper proposes a new switched capacitor nine-level (9L) inverter with reduced switch count. In the proposed topology, floating capacitor (FC) is employed as a voltage booster and it does not need any additional sensors to maintain the voltage across the FC. Due to additional FC, the number of dc sources and voltage stress on switches is reduce...

The series photovoltaic-battery-hybrid (PVBH) system is considered as a promising solution to better integrating distributed energy sources. However, the state-of-the-art controls are either highly dependent on the communication, by which real-time control variables should be transmitted among all converters, or only suitable for PVBH systems with...

Field experiences have shown that sub-synchronous oscillation (SSO) can occur in direct-drive wind farms with VSC-HVDC systems. Due to the complexity of the detailed wind farm model, a dynamic equivalent model, with a reasonable order reduction of the detailed model and still reflecting inside-wind-farm and wind-farm-grid SSO characteristics is ess...