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30 October 2025, Volume 23 Issue 6
  

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    DC-DC Converters
  • Research on Charge Active Disturbance Rejection Control Strategy for LLC Resonant Converter
    CHEN Zongxiang, ZHAO Xinyu, ZHANG Wulin, LIU Kang, LI Song
    2025, 23(6): 1-9. https://doi.org/10.13234/j.issn.2095-2805.2025.6.1
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aimed at the problem that it is difficult for an LLC resonant converter to strike a balance between its dynamic performance and disturbance rejection capability in applications with high dynamic demand and frequent load changes, a charge active disturbance rejection control strategy is proposed. In this method, charge control is carried out in the inner loop of the resonant converter by collecting the resonant capacitor voltage, and active disturbance rejection control is introduced in the outer loop to form a compound control strategy of dual-closed-loop control. By deducing the relationship between the resonant capacitor voltage and resonant current of the LLC resonant converter, the controller parameters in the inner voltage loop of the converter are designed by using the charge control method, and an outer voltage loop controller is designed based on linearized active disturbance rejection control, thus further improving the anti-interference capability of the whole system. An experimental prototype with rated power of 300 W was designed and built, and the feasibility and effectiveness of the improved control strategy was verified by comparing with the traditional PID-PI control.
  • Review of Optimization Methods for Switch Mode Power Supply Based on LLC Resonant Converter
    GU Yanjie, Student Member, CPSS, YU Renjie, ZHANG Yan, Member, CPSS
    2025, 23(6): 10-22. https://doi.org/10.13234/j.issn.2095-2805.2025.6.10
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The DC-DC converter in a switch mode power supply (SMPS) is the core part that affects the device’s volume, weight and working efficiency. As a classic DC-DC topology, the LLC resonant converter uses the soft switching technology and magnetic integration technology, which has characteristics such as a high efficiency, a high power density and harmonics suppression. The research status of optimization methods for LLC resonant converters applied in SMPS is reviewed, starting from the transformer winding structure schemes and control topology optimization schemes. In addition, suggestions on the effects of synchronous rectification and the planar transformers under an all-primary-referred (APR) magnetic integration model on the circuit are given. Finally, the optimization methods based on the third-generation wide bandgap material and electromagnetic compatibility are prospected.
  • Optimal Design of Integrated High-frequency Transformer for LLC Resonant Converter Based on Finite Element Simulation
    GU Zeyu, XIE Xiaogao, Member, CPSS
    2025, 23(6): 23-31. https://doi.org/10.13234/j.issn.2095-2805.2025.6.23
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    The air gap in an integrated high-frequency transformer of an LLC resonant converter is usually placed at the center of magnetic core, and a single air gap structure is adopted. The nonlinear three-dimensional transformer models with different air gap positions are established using a finite element analysis method based on the software Ansys, and the influence of air gap position on loss is studied. Through simulations, the curves of loss versus air gap positions are obtained, and it is proved that the loss of transformer can be reduced and the converter efficiency can be improved if the air gap is located in the region of secondary windings, providing a reference for the optimal design of the integrated high-frequency transformer. On this basis, an integrated high-frequency transformer structure with three air gap magnetic circuits on the secondary side is proposed, so as to further reduce the transformer loss. Finally, an experimental prototype of a 160 W LLC dimmable LED driver was built, and experimental results verified the correctness and feasibility of the proposed method.
  • Optimization Method for Backflow Power of Half-bridge CLL Resonant Converter Based on Equivalent Resonant Cavity
    HUANG Hewei, Student Member, CPSS, CAO Taiqiang, LI Wei, GUO Junhong
    2025, 23(6): 32-44. https://doi.org/10.13234/j.issn.2095-2805.2025.6.32
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aimed at the problem of backflow power generated by a half-bridge CLL resonant converter, a parameter design method based on the equivalent resonant cavity is proposed to optimize the backflow power and improve the conversion efficiency. First, according to the operating characteristics of an LLC converter, it is concluded that the value of backflow power can be characterized by the zero-crossing time of resonant current. Under the conditions of satisfying the voltage gain and zero-voltage switching of a switch on the primary side, the optimal resonant cavity parameters are selected according to the function curve representing the backflow power. Second, through the quantitative relationship between the CLL and the LLC resonant cavity, the resonant cavity is adjusted to be equivalent, so that the CLL has the same backflow power characteristics as the LLC. Finally, two sets of resonant cavity parameters meeting the design conditions were used for comparison and verification through simulations and experi-ments. Resultsshow that under the condition of equivalent resonant cavity, both converters had the same zero-crossing time of resonance current, and the conversion efficiency was improved by about 1.3% under the conditions of quasi-resonance and full load, thus verifying the correctness and feasibility of theoretical analysis.
  • Optimization Control Strategy for Dual Active Bridge Converter under New Phase Shift Angle
    LIU Xiaoyue, LI Yue, LIU Feilong
    2025, 23(6): 45-56. https://doi.org/10.13234/j.issn.2095-2805.2025.6.45
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    The typical isolated dual-active bridge (DAB) converter with a simple circuit structure and easy control is widely applied under scenarios where the bidirectional energy flow is required. Therefore, it is particularly important to study how to improve the working efficiency of the converter. First, the efficiency optimization strategies proposed by domestic and foreign scholars are compared and analyzed, and it is found that the intra-and inter-bridge phase shift angles on two sides have a strong correlation, which causes the difficulty in analyzing the working characteristics of the converter. Second, the rectified average current of the converter based on extended-phase-shift (EPS) control is optimized, a new phase shift angle is defined, and the transmission power and average current of the converter under the new phase shift angle are analyzed. Finally, a simulation platform based on Simulink and an experimental platform were set up for verification.
  • Backflow Power and Inductance Peak Current Optimization Strategy for Dual-active-bridge DC-DC Converter with Triple-phase-shift
    YANG Kangyi, CHEN Difa, CHEN Yanhui
    2025, 23(6): 57-65. https://doi.org/10.13234/j.issn.2095-2805.2025.6.57
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    A dual-active-bridge DC-DC converter is taken as the research object, and a triple-phase-shift (TPS) control strategy with an optimization objective of reducing the backflow power and inductance peak current is proposed. Through the analysis of characteristics in six operating modes with TPS, the input-side zero-backflow power mode and bilateral zero-backflow power mode with smaller inductance peak current in Boost and Buck modes are obtained, and the constraint of phase-shift ratio and power range in different operating modes are given. The inductance peak current in bilateral zero-backflow power mode is smaller, and the zero switching of the power device can be realized. On this basis, the working point with the smallest inductance peak current at different values of transmission power is further obtained through optimizations using the KKT method. Finally, the proposed TPS optimization method and the inductance peak current optimization method under extended-phase-shift were verified by experiments. Experimental results show that the proposed optimization strategy can eliminate the backflow power, reduce the current stress and improve the conversion efficiency, thus verifying the theoretical analysis.
  • Dynamic Response Optimization Method for Multi-phase Interleaved Buck Converter Based on Model Predictive Control
    ZHANG Peng, Member, CPSS, LIU Yang, WANG Weikang, CHEN Zhixiu, XIA Ye
    2025, 23(6): 66-75. https://doi.org/10.13234/j.issn.2095-2805.2025.6.66
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    Aimed at the problems of insufficient dynamic performance and poor robustness in the traditional linear control, a dynamic response optimization method based on the model predictive control of a multi-phase interleaved Buck converter is proposed in this paper. First, the state space model of the interleaved Buck converter is optimized, and a virtual impedance method is put forward to realize the decoupling control of each phase converter. Second, a load disturbance observer and a continuous set model predictive controller based on one-step prediction are designed. The reference current is calculated based on the load current observation and the output voltage deviation, and the optimal duty cycle in each phase is obtained by substituting it into the predictive model with an objective of minimizing the current deviation. Finally, a simulation platform was built on Matlab/ Simulink for simulation verification, and experiments were conducted on a three-phase Buck converter. Simulation and experimental results show that the proposed algorithm can effectively suppress the output voltage variations caused by load disturbances, improve the dynamic performance of the system, and ensure its robustness at the same time.
  • Variable Universe Fuzzy PI Predictive Control for Novel On-board Charging DC-DC Converters
    SHANG Junjie, Student Member, CPSS, CAO Taiqiang, LIN Xuan, DAI Jin, ZHENG Min
    2025, 23(6): 76-85. https://doi.org/10.13234/j.issn.2095-2805.2025.6.76
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    Aimed at the problems in traditional on-board charging DC-DC converters such as a narrow soft switching range, poor dynamic response and rectifier diode voltage spike, a novel wide-range soft switching full-bridge converter is designed, and a double-closed-loop control strategy combining variable universe fuzzy PI with model prediction is adopted. First, the working mode of the novel full-bridge converter is analyzed, and its simplified state space average model is established. Second, model predictive control is used in the current loop, and compensation improvements are made to obtain the predictive expression of inductance current at the time point of k+2, thereby improving the large time delay of an actual system. Third, the control of voltage loop is changed to the transform domain fuzzy PI control with fuzzy universe self-adaptation, so as to optimize the system adaptability and improve the control precision. Simulation results show that the soft switching range of the novel converter is extended to 30% of load, and the rectifier diode voltage spike is also eliminated. Under sudden changes in load, the proposed control strategy reduces the output voltage regulation time by 17.8% and 25.6%, as well as 12.9% and 9.1%, respectively. Finally, the effective-eness of the proposed topology and control strategy was verified by experimental results.
  • Passivity-based Adaptive Control of Boost Converter Based on Neural Network
    WANG Lu, WANG Jiuhe, ZHAO Yan, LI Jianguo, ZHANG Yajing, Member, CPSS
    2025, 23(6): 86-94. https://doi.org/10.13234/j.issn.2095-2805.2025.6.86
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To improve the dynamic performance of passivity-based control (PBC) of a Boost converter with constant power load under external disturbances, a passivity-based adaptive control strategy based on neural network was proposed. Under this strategy, a passivity-based adaptive control structure with proportional and integral terms was adopted, and a single-neural network was used to optimize the injection damping, proportional coefficient and integral coefficient in real time. In addition, a power observer was used to observe the power of unknown constant power load (CPL) in real time, thus improving the dynamic and steady-state performances of the Boost converter when the CPL changes. Compared with PI+PBC and PI double-closed-loop control strategies, the passivity-based adaptive control based on neural network can make the Boost converter have a better performance. The results of computer simulations show that the proposed control strategy is feasible.
  • Current-sharing Control Strategy for Input-series Output-parallel Combined System
    QU Lu, LIU He, TONG Qiang
    2025, 23(6): 95-104. https://doi.org/10.13234/j.issn.2095-2805.2025.6.95
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    The input-series output-parallel combination technology for DC-DC converters is widely applied in high-power and high-voltage fields. To realize an average operation after the expansion and connection of modules, the characteristics of input voltage-sharing and output current-sharing after the series-parallel combination of module power supplies are studied, and a control strategy for module current-sharing on the output side is proposed, which consists of an output voltage loop and an output current-sharing loop. The common output voltage loop of all the modules samples the output voltage from the combined system for feedback regulation, while the output current-sharing loop of each module samples the output current from the module for average control. All the sampling and control chips under the proposed control strategy are on the low-voltage output side, which can eliminate an isolation unit and improve the system reliability. A half-bridge LLC resonant topology was selected as a sub-module to build a prototype, and results verified the effectiveness of the proposed output current-sharing control method.
  • Output-capacitorless LDO Regulator with Fast Transient Response
    CHENG Tiedong, TAN Zehui, XU Lijun, XU Zhenxuan
    2025, 23(6): 105-113. https://doi.org/10.13234/j.issn.2095-2805.2025.6.105
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    In view of the poor tiansient response of the output-capacitorless, an output-capacitorless low dropout (LDO) regulator with fast transient response is proposed, and the voltage overshoot and undershoot suppression circuits are used to suppress voltage jumps, thus improving the transient response characteristics of the LDO regulator. An improved error amplifier is designed, whose gain is larger than that of a general error amplifier in static working states. In addition, the transient output current from the designed error amplifier can be increased when the output voltage jumps, and the charging and discharging of the power tube can be accelerated. By using Current buffer Miller compensation, the phase margin of the circuit is compensated with a smaller capacitive area. Simulation results show that when the voltage range is 2.8~3.3 V, the output voltage from the circuit is 1.8 V and the maximum load current is 50 mA. When the load current jumps between 1 and 50 mA, the undershoot amplitude of output voltage is reduced by 46 mV (51%) and the response time is 1.16 µs under the effect of the transient enhancement circuit. Meanwhile, the overshoot amplitude is reduced by 29 mV (35%), and the response time is 1.18 µs.
    • DC-AC Inverters
  • Frequency Self-adaptive and Selective-order Harmonic Repetitive Control Strategy for Grid-connected Converter under Non-ideal Grid Conditions
    HU Licong, Student Member, CPSS, LU Wenzhou, Senior Member, CPSS, WANG Wei, ZHOU Keliang, ZHOU Xiaoqi
    2025, 23(6): 114-122. https://doi.org/10.13234/j.issn.2095-2805.2025.6.114
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Under the non-ideal conditions of grid such as frequency fluctuation due to the access of various new energy to power system, the quality of grid-connected current of a grid-connected converter will be seriously degraded under the traditional repetitive controller with fixed parameters. Therefore, it is important to improve the frequency self-adaptability of the grid-connected converter under non-ideal grid conditions. To solve this problem, a frequency self-adaptive and selective-order harmonic repetitive con-troller ( FSA-SHRC) is proposed, which can accurately approximate and compensate the part of parameter trans-formation due to fundamental frequency fluctuation by com-bining the internal mode with an infinite impulse response ( IIR) filter. Compared with the conventional repetitive controller, the proposed FSA-SHRC has advantages of fewer memory cells required by the internal mode, a better error convergence rate and an accurate performance, and it has certain frequency adaptive performance by tuning the coefficients of IIR online when the fundamental frequency fluctuates. FSA-SHRC was applied to a three-phase grid-connected inverter control system, and the superiority of the theory and the corresponding adaptability under non-ideal grid conditions were verified.
  • Differential Flatness Control Strategy for Grid-connected Inverter Based on Virtual Synchronous Generator Control
    LI Ziyang, Member, CPSS, WANG Hongxi, WANG Pu, WANG Yongchen
    2025, 23(6): 123-131. https://doi.org/10.13234/j.issn.2095-2805.2025.6.123
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    To solve the problems of slow dynamic response speed and poor robustness in the conventional voltage and current dual-closed-loop control for grid-connected inverters based on virtual synchronous generator (VSG) control, a novel dual-closed-loop control strategy for VSG based on the differential flatness theory was proposed. First, a mathematical model under the dq coordinate axis was established according to the topology of a three-phase grid-connected inverter, and the flatness of the system was proved based on the differential flatness theory. Second, a voltage and current differential flatness controller including feedforward reference locus and error feedback compensation was designed. Finally, a simulation model of the system was constructed in MATLAB/Simulink. Simulation results show that the proposed control strategy improves the dynamic response speed and robustness of the VSG-based grid-connected inverter under the operating conditions of power disturbance and three-phase short-circuit fault of the grid, thereby verifying the effectiveness and feasibility of the differential flatness control strategy when it is applied to VSG.
  • Optimal Control Strategy for Multi-functional Grid-connected Photovoltaic Inverter
    JIANG Zhoupeng, HAO Wubang, LI Yan
    2025, 23(6): 132-141. https://doi.org/10.13234/j.issn.2095-2805.2025.6.132
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    With the higher requirements for the safety and stability of traditional power grids, the energy crisis and environmental pollution problems are increasing. As a result, “Green” and “Low carbon” have become the urgent needs of the development of power systems. Based on the current situation, a multi-functional photovoltaic grid-connected inverter with power quality control is proposed. First, according to an improved adaptive harmonic detection method, the harmonic component in the grid-connected current is detected. Second, the command current is tracked and controlled by quasi-proportional resonance. Through the subjective and objective criteria importance through intercriteria correlation (CRITIC) game theory combination weighting method, a comprehensive evaluation model of power quality is established to evaluate the harmonic and reactive components. Third, considering the limited capacity of the inverter in practice, a capacity matching coefficient is formulated to compensate the dominating problems. Finally, simulation results show that the harmonic and reactive components are optimized and compensated in the grid-connection process of the inverter, which improves the power quality at the grid-connected point and greatly increases the utilization rate of the inverter. Therefore, the effectiveness and feasibility of the proposed strategy are verified.
  • Robust Backstepping Control Strategy for Grid-connected Inverter Based on Weighted Average Current
    ZHOU Zichun, HE Guofeng, Member, CPSS, LUO Shuang, LI Guojiao
    2025, 23(6): 142-151. https://doi.org/10.13234/j.issn.2095-2805.2025.6.142
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    To solve the problems of computational complexity and exponential amplification of measurement noise under the traditional backstepping control strategy applied to an LCL grid-connected inverter, an improved backstepping control strategy based on weighted average current control (WACC) is proposed in this paper. First, the order of the LCL filtering system is reduced from third-order to first-order by means of the WACC strategy, which effectively alleviates the overall computation load and decreases the number of derivations required for virtual control quantities. Then, a sliding-mode observer is utilized to observe the weighted average current, so as to lessen the influence of LCL filter parameter perturbation on the accuracy of weighted average current. Finally, a backstepping controller is designed to regulate the grid-connected current based on the established equivalent system model. Simulation and experimental results prove that the proposed control strategy has a good steady-state performance and high robustness.
  • DC Offset Suppression Strategy for Quasi-Z-source Inverter Based on Observer under Weighted Average Current Control
    LIN Junfang, HE Guofeng, Member, CPSS, ZHOU Zichun, WANG Hang
    2025, 23(6): 152-161. https://doi.org/10.13234/j.issn.2095-2805.2025.6.152
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    Aimed at the issue of DC offset injection to the grid when the topology of a quasi-Z-source grid-connected inverter without isolation transformer is adopted, a DC offset suppression strategy based on an observer under weighted average current control is proposed in this paper. First, the topology of the quasi-Z-source inverter and the causes of DC offset are analyzed. Second, the order of an LCL filter is reduced from the third-order to first-order by weighted average current control, thus simplifying the system model and eliminating the resonance problem. Then, a disturbance observer is utilized to observe the DC offset of inverter output voltage in realtime, the DC offset disturbance is dynamically compensated by feedback, and its stability is analyzed. Finally, the proposed strategy was validated by experiments. Experimental results show that the proposed strategy can effectively reduce the DC offset of grid-connected current, meet the grid-connected DC offset requirement of less than 0.5%, and ensure good steady-state and dynamic performances of the inverter.
    • AC-DC Converters
  • Research on High-power Electrolytic Hydrogen Production Power Supply with High Reliability and High Efficiency
    HE Mingzhi, TAN Yang, MENG Xin, CHEN Maolin
    2025, 23(6): 162-171. https://doi.org/10.13234/j.issn.2095-2805.2025.6.162
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    To address the problem that phase-controlled and fully-controlled rectifiers cannot combine high power level, high hydrogen production efficiency and high reliability in the field of electrolytic hydrogen production at present, a hybrid rectifier topology which consists of a main power rectifier and an auxiliary converter in parallel and its control strategy are proposed. The main power rectifier is a thyristor rectifier, and the auxiliary converter consists of a pulse width modulated voltage source converter and a phase-shifted full-bridge converter in cascade. Through an analysis of the mathematical model of the auxiliary converter, the compensation of ripple current and the absorption of harmonic current are taken as control objectives, and a current control method of repetitive control with proportional resonance control is given to realize an efficient operation of the hydrogen production unit while optimizing the input current quality. In addition, three fault-tolerant operation modes of the hybrid rectifier topology are proposed to improve its reliability. An electrolytic hydrogen production platform was built and semi-physical simulations were performed to verify the hybrid rectifier topology and its control strategy, and results proved the topology’s correctness and effectiveness.
  • Improved Power Control Strategy for Vienna Rectifier under Asymmetric Grid
    GAO Liang, ZHANG Qingyan, HU Yebo
    2025, 23(6): 172-179. https://doi.org/10.13234/j.issn.2095-2805.2025.6.172
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    Aimed at the problems of active power fluctuation and current asymmetry of a Vienna rectifier caused by asymmetric grid, active power fluctuation suppression control (APFSC) and symmetric positive-sequence current control (SPSCC) are introduced. Due to the current limitation of power devices, the use of APFSC will reduce the maximum active power of the Vienna rectifier. In comparison, the use of SPSCC can expand its maximum active power at the cost of significant active power fluctuation. With the comprehensive consideration of disadvantages of the above two methods, an improved power control (IPC) strategy is proposed. When the processing power of the Vienna rectifier is small, keeping the active power without fluctuation is the primary control target. In this case, the effects of IPC and APFSC are the same. The active power fluctuation under IPC is effectively suppressed, while that under SPSCC is large. When the processing power of the Vienna rectifier is large, meeting the power demand is the primary control target, but the active power fluctuation should be reduced as much as possible. Under this circumstance, IPC can meet the active power demand, but APFSC cannot meet the power demand. On the premise of meeting the power demand, the fluctuation of active power under IPC is smaller than that under SPSCC. Finally, experimental results verified the advantage of the proposed control method.
    • AC-AC Converters
  • Electrified Railway Dual-network Interconnection Converter with Current Limiting
    LIU Yijun
    2025, 23(6): 180-189. https://doi.org/10.13234/j.issn.2095-2805.2025.6.180
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    The contradictions faced in practical engineering and design have proved the necessity and urgency of research on electrified railway dual-network interconnection converters. The major needs and engineering challenges in practical applications of dual-network interconnection converters are analyzed. According to the characteristics of the railway electric power supply and distribution network, a topological structure of an electrified railway dual-network interconnection converter with current limiting is proposed, its working principle and composition are analyzed in detail, and its variable impedance control strategy in voltage control mode and current limiting switching control mode is put forward. Moreover, the feasibility of the variable impedance control strategy is proved by a simulation model. In particular, an engineering prototype was used to prove that the voltage control mode of the converter has good practicability, and it can solve the difficulty in actual survey design, high cost, power quality degradation and other issues. Finally, the development potential of the interconnected converter in the future is prospected.
    • Modeling and Control
  • Equivalent Mechanism and Simulation Analysis of Current-Internal Voltage and Terminal Voltage-Current Excitation-response Characteristics of Grid-connected Converter
    FU Tianzhao, YUAN Xiaoming, Senior Member, CPSS, GONG Xuan
    2025, 23(6): 190-198. https://doi.org/10.13234/j.issn.2095-2805.2025.6.190
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    During the dynamic process of a system, the current control of a converter realizes a balance between current and reference by adjusting the output voltage when the grid-side current changes, which is represented as voltage response under the current excitation. Since the AC voltage of the converter is generated by controlling the amplitude/frequency and the amplitude/frequency of voltage is required to be maintained during the system operation, the current control should be described as the internal voltage amplitude/frequency response under active/reactive current excitation when a power imbalance occurs. At the same time, from the perspective of a grid-connected converter’s influence on the grid, the active/reactive current response under the terminal voltage amplitude/frequency excitation is another perspective for understanding the characteristics of the grid-connected converter. Therefore, for the current control of the converter, the active/reactive current-internal voltage characteristics used in the dynamic analysis of large systems and the terminal voltage-active/reactive current characteristics from the perspective of the influence of equipment (e.g., single machine) on the grid are presented. On this basis, it is determined that the two kinds of characteristics are essentially equivalent by explaining the redundant relationship between current and terminal voltage under the current control. Finally, the equivalence is verified by simulations, and the influence of phase-locked control parameters on current control characteristics is preliminarily explored.
  • Fault-tolerant Control Method for Cascaded H-bridge Multilevel Converter
    ZHU Xu, Student Member, CPSS, HU Changsheng, Member, CPSS, DONG Bitao, Student Member, CPSS
    2025, 23(6): 199-207. https://doi.org/10.13234/j.issn.2095-2805.2025.6.199
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    A cascaded H-bridge (CHB) multilevel inverter is composed of many unit modules, and the probability of failure is relatively high. The fault-tolerant operation can effectively improve the reliability and performance of a system. By injecting zero-sequence voltage to enhance the output capability after fault, the fault-tolerant control method has advantages of not adding any additional cost and simple implementation. As a result, it has attracted wide attention. The zero-sequence voltage value and fundamental component value injected by different implementation methods are different, and an excessive zero-sequence voltage will have a great impact on the motor bearing and insulation in the motor drive. Aimed at this problem, a zero-sequence voltage (containing third harmonic component) injection method is discussed to reduce the fundamental component of injected zero-sequence voltage, so as to decrease the influence of injected zero-sequence voltage on the motor operation. The effectiveness of the proposed fault-tolerant control strategy was verified by simulations and a 10 kW 7-level converter prototype.
    • Renewable Energy System
  • Wide-frequency Operation Control Method for Double-fed Wind Power Generation System Connected to Medium-voltage DC Grid with Uncontrolled Rectifier
    CUI Xueshen, Member, CPSS, LIU Yongxin, ZHANG Qiwei, LUO Huida, LIU Qihui
    2025, 23(6): 208-217. https://doi.org/10.13234/j.issn.2095-2805.2025.6.208
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    The connection of distributed generations to DC grid can improve the consumption level of new energy. In view of the fact that the doubly-fed wind turbine is connected to medium-voltage DC grid through a diode uncontrolled rectifier, a wide-frequency operation control method is proposed, which can limit the rotor-side feed power in the whole wind speed range and further greatly reduce the cost of a rotor-side converter. When the wind speed and rotational speed are high, the stator frequency is properly increased, and the rotor-side power is limited to a small constant power with a certain negative slip. When the wind speed is low, the rotor-side power is operated at a constant stator frequency lower than the power frequency, so as to make the slip rate change positively or negatively in a small range and limit the absolute value of rotor-side power accordingly. A simulation example is taken, in which the absolute value of rotor-side power of a 1.5 MW doubly-fed wind turbine is limited within 140 kW in the full wind speed range, and results verify the effectiveness of the proposed wide-frequency operation control method in reducing the capacity of the rotor-side converter. Finally, the feasibility of the proposed wide-frequency operation control technology was verified through a laboratory-scale experimental platform of 5.5 kW doubly-fed unit connected to DC grid with uncontrolled rectifier.
  • Hybrid DC Energy-consuming Device for Offshore Wind Power DC Transmission System and Its Modulation Strategy
    LI Feng, PENG Sui, WANG Yanfeng, YU Hao, REN Zijun, QU Xiaohui, Member, CPSS
    2025, 23(6): 218-226. https://doi.org/10.13234/j.issn.2095-2805.2025.6.218
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    In a flexible DC transmission system for offshore wind power generation, surplus power will be generated in the system when the land end is greatly unloaded or the AC system fails, resulting in a rapid increase in the DC transmission voltage. A DC energy-consuming device can quickly dissipate the surplus power, which is a key technical solution to ensuring smooth fault ride-through and reliable operation of the system. However, the modulation voltage of the energy-consuming valve will become negative when the surplus power is large. To solve this problem, a hybrid DC energy-consuming device based on half-bridge and full-bridge sub-modules and its modulation strategy are proposed in this paper. By using the negative-voltage output capability of the full-bridge sub-module, the matching range of the surplus power can be expanded, and the recovery speed of DC voltage can be speeded up. The effectiveness of the proposed energy-consuming device and its modulation strategy is verified through theoretical analysis. Besides, a simulation model of the offshore wind power flexible DC transmission system was built on a PSCAD/EMTDC electromagnetic tran-sient simulation platform, and the feasibility of the proposed DC energy-consuming device and corresponding modulation strategy was verified under conditions of different values of surplus power.
  • Research on Low Voltage Ride-through Capability of Permanent Magnet Synchronous Generator Used in Wind Power Generation Based on SDBR-SCESS
    LIN Haidong, KUANG Honghai, ZHANG Qunfeng, WANG Jun, YU Xiqi
    2025, 23(6): 227-236. https://doi.org/10.13234/j.issn.2095-2805.2025.6.227
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To improve the low voltage ride-through capability of a permanent magnet synchronous generator (PMSG) grid-connected wind power system, a coordinated control method based on series dynamic braking resistors (SDBR) and a supercapacitor energy storage system (SCESS) is proposed. When the grid voltage drops, the SDBR connected in series across the grid will consume part of the unbalanced energy while raising the voltage at the grid-connected point, and the remaining unbalanced energy will be absorbed by the SCESS connected in parallel to the DC chain. Simulation results based on MATLAB/SIMULINK show that the SDBR-SCESS coordinated control strategy can effectively suppress the peak DC chain voltage and raise the voltage at the grid-connected point under fault, reduce the peak grid-connected current at the moment of fault removal, effectively shorten the recovery time of DC chain voltage and grid-connected current after fault removal, and improve the low voltage ride-through capability of the PMSG. Compared with the control based on SDBR or SCESS alone, the SDBR-SCESS coordinated control has a superior effect.
  • Research on Prefiltering Phase-locked Loop Based on SOGI and CDCCF
    SHI Jing, YANG Jun, WEN Long, SHEN Junqing, CHE Guanglei, LI Songxuan
    2025, 23(6): 237-246. https://doi.org/10.13234/j.issn.2095-2805.2025.6.237
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Phase-locked loop (PLL) is one of the important structures to control photovoltaic inverters to realize grid-connected synchronization. Aimed at the problem that α-PLL will have large errors in the detection frequency and phase when unbalanced faults and harmonic interference occur in power grid, a novel prefiltering PLL (PFPLL) based on cross decoupling complex coefficient filter (CDCCF) and second-order generalized integrator (SOGI) is proposed in this paper. The SOGI with the capability of eliminating specific-order harmonics is used as the prefiltering link of PFPLL, and the CDCCF with a feedback loop is used as the signal decoupling link of PFPLL. The proposed PFPLL structure can eliminate voltage imbalance and harmonic components, thus realizing the frequency self-adaptation. A simulation model and an experimental platform were built, and results verified the filtering capability of PFPLL.
    • Wireless Power Transfer
  • Design and Optimization of Novel Solenoid Magnetic Coupler for Electric Boats Wireless Charging
    WANG Wei, WANG Shuo, LÜ Xiaofei, DOU Zhenlan
    2025, 23(6): 247-257. https://doi.org/10.13234/j.issn.2095-2805.2025.6.247
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The wireless charging technology for electric boats charging applications has gradually attracted attention. Due to the long wireless charging transmission distance of electric boats, the coupling coefficient and anti-misalignment capability of a magnetic coupler will decrease sharply with an increase in the transmission distance, thus reducing the transmission efficiency and output power. A novel solenoid magnetic coupler is proposed, and the finite element simulation models of magnetic couplers with different structures are built to compare their performance. In addition, the proposed solenoid magnetic coupler is optimized, and the corresponding magnetic shielding device is configured. Compared with those of the traditional solenoid magnetic coupler, the use of magnetic core and Litz wires of the novel solenoid magnetic coupler are reduced by 32% and 38%, respectively, thus effectively improving its coupling coefficient and anti-misalignment capability. Finally, a set of wireless charging prototype was built, and the transmission efficiency can reach 88%. The experimental results were consistent with the simulation results.
  • Metal Object Detection Method for WPT System with Vertically Decoupled Coil Sets
    XIANG Fei, ZHONG Wenxing, Member, CPSS
    2025, 23(6): 258-266. https://doi.org/10.13234/j.issn.2095-2805.2025.6.258
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    For a wireless power transfer system with one single planar rectangular pad, a metal object detection (MOD) method based on vertically decoupled coil sets is proposed. The detection coils are combined in a reasonable manner to form a detection coil set, which is decoupled from the transmitting and receiving coils simultaneously. When there is no metal object, the induced voltage of the detection coil set will be close to zero and minimally affected by the offset of the receiving coil. When a metal object falls on the top of the transmitting coil, eddy currents will be generated and induced voltage will appear in the detection coil set. The detection accuracy of the proposed method is not significantly affected by the offset of the receiving coil, and there is no need to reset the detection circuit or adjust the threshold for different offset positions. The parameters of the detection coil are optimized by finite element simulations. Based on a 300 W wireless charging system, MOD experiments were conducted, and results show that the proposed method can accurately identify metal objects even in offset situations. This method solves the problem of a planar detection scheme being affected by the offset of the receiving coil, with high detection sensitivity and great engineering application value.
    • Battery and Energy Storage
  • RUL Prediction of Lithium-ion Batteries Based on PCA-CEEMDAN and Improved SVR
    WU Weili, LU Shuangshuang
    2025, 23(6): 267-280. https://doi.org/10.13234/j.issn.2095-2805.2025.6.267
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aimed at the problems that the capacity of a lithium-ion battery is difficult to obtain in the direct prediction of its remaining useful life (RUL) and the characteristic parameters are redundant or insufficient in the indirect prediction, an indirect prediction method for the RUL of lithium-ion battery based on the data preprocessing technology and improved support vector regression (SVR) is proposed. First, multiple indirect characteristic parameters are extracted at the battery charging and discharging stage. Second, principal component analysis is used to remove the redundancy of various parameters, and a fusion health indicator (HI) with sufficient information is reconstructed. Third, a fusion HI prediction model and a capacity prediction model based on the whale optimization algorithm and SVR are built, and the complete ensemble empirical mode decomposition with adaptive noise is used to decompose the fusion HI into several modal components. Each component is input into the fusion HI prediction model for HI prediction, and the prediction results are superimposed into the capacity prediction model to realize indirect RUL prediction. Finally, the NASA battery degradation data set is used for verification, and results show that the mean absolute error and root mean square error of RUL prediction results for the proposed method are controlled within 1.78 % and 2.5 %, respectively, which effectively improves the prediction accuracy of RUL. The research provides a new idea for the RUL prediction of lithium-ion batteries.
  • Optimization Design of PCM-Air Cooling Coupled Lithium-ion Battery Cooling System
    XU Jing, XIANG Feifei, WANG Xiang, XU Xin, SHI Suhang
    2025, 23(6): 281-287. https://doi.org/10.13234/j.issn.2095-2805.2025.6.281
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    In view of the poor cooling effect on a lithium-ion battery module (LIBM) when using one single cooling method, a phase change material (PCM)-air cooling coupled battery cooling system was proposed. First, the influences of different inlet air velocities (IAVs), battery gaps (BGs) and inlet air temperatures (IATs) on the highest temperature and maximum temperature difference of LIBM were discussed. Second, with the IAV, BG and IAT as design variables and the highest temperature and maximum temperature difference as objective functions, the design variables and objective functions were numerically fitted by a response surface model. Third, the non-dominated sorting genetic algorithm-II is used to optimize and predict the response surface model. Finally, the optimization and prediction results were verified by simulations based on computational fluid dynamics. Results show that the optimized cooling system can reduce the highest temperature in LIBM by 4.68 ℃ (13.8%) and the maximum temperature difference by 0.57 ℃(30.3%).
  • SOH Prediction of Electric Vehicle Lithium Battery Based on Integrated Model of Variation Modal Decomposition and Kernel-based Extreme Learning Machine
    WU Chunling, LÜ Jingjing, XIANGLI Kang, MENG Jinhao, HUANG Xinrong, ZHANG Zhen
    2025, 23(6): 288-299. https://doi.org/10.13234/j.issn.2095-2805.2025.6.288
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In the traditional prediction of lithium batteries for electric vehicles, the state-of-health (SOH) prediction is usually regarded as a whole, and the result of single SOH prediction is obtained accordingly. However, in the actual operation of a car, the single prediction of SOH has a large error, and its prediction effect is not satisfying. To improve the accuracy of battery SOH prediction for electric vehicles, a novel prediction method based on variational modal decomposition (VMD) and sparrow search algorithm (SSA) optimization of kernel-based extreme learning machine (KELM) integrated prediction model, i.e., VMD-SSA-KELM, is proposed. First, the battery SOH sequence is decomposed by VMD to reduce the influence of SOH fluctuations. Meanwhile, the Person correlation method is used to reduce the influence of noise and improve the accuracy of prediction. The KELM is introduced, which improves the accuracy of prediction while retaining the advantages of extreme learning machine. The proposed model is validated based on the operation data of four electric vehicles, and experimental results show that compared with the VMD-DBO-KELM, VMD-POA-KELM, VMD-KELM and VMD-ELM models, the proposed model has a prediction trend which is the same as that of the original data, while the results of other models fluctuate a lot. The root mean square error of results predicted by the novel model is less than 0.2%, the prediction accuracy becomes higher, the prediction efficiency is faster and the time used is shorter, indicating that the proposed method has higher accuracy and better robustness.
  • High-precision OCV-SOC Curve Acquisition Method for LiFeO4 Battery
    LIN Jiashun, ZHOU Juan, Member, CPSS, WU Naihao, Student Member, CPSS, YANG Xiaoquan
    2025, 23(6): 300-308. https://doi.org/10.13234/j.issn.2095-2805.2025.6.300
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    The accurate open-circuit voltage-state of charge (OCV-SOC) curve is a basis for ensuring the modeling accuracy of lithium-ion battery. The OCV-SOC curves of LiFeO4 battery obtained by a low-current OCV test cannot describe the OCV characteristics at a non-testing point, while those obtained by an incremental OCV test are interfered by the polarization effect. Therefore, based on the analysis of the characteristics of LiFeO4 battery, a high-precision OCV-SOC curve acquisition method for LiFeO4 battery is proposed by combining the low-current OCV test and incremental OCV test. This method takes the incremental discharge curve which is fitted in piecewise form as its optimization object, designs constraints based on the low-current OCV test data and first-order RC equivalent circuit model, and uses the differential evolution method to acquire the OCV-SOC optimization curve. Experimental results show that the OCV-SOC optimization curve can accurately simulate the OCV characteristics of LiFeO4 battery. Compared with the OCV-SOC curve obtained by the low-current OCV test, the battery modeling and SOC estimation based on the OCV-SOC optimization curve has a higher accuracy, with the model accuracy increasing by 41.8% and SOC estimation accuracy increasing by 58.3%.
  • Model Predictive Control-based Energy Management Strategy for Fuel Cell Buses
    XU Xin, Student Member, CPSS, WU Xiaohua, Member, CPSS, YANG Jialuo, SHU Junhao
    2025, 23(6): 309-319. https://doi.org/10.13234/j.issn.2095-2805.2025.6.309
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To improve the fuel economy of fuel cell buses, an energy management strategy based on model predictive control was proposed to solve the problem that the rule-based energy management strategy depends on engineering experience and parameter calibration. This strategy was implemented in a layered control manner to reduce the amount of computation. At the top level, a dynamic programming energy management strategy was used to determine the best reference trajectory for the lithium battery’s state-of-charge (SOC). At the bottom layer, radial basis function neural network was used to predict the future vehicle speed, with the goal of predicting the efficient output of fuel cell power and SOC to follow the best reference trajectory in the time domain. In addition, the optimal decision making on power distribution was solved by the quadratic programming algorithm. The determination of the speed prediction model and prediction time-domain, the influence of SOC reference trajectories on the proposed strategy, and the changes in SOC and fuel economy under different strategies were studied in detail. Results show that when the initial SOC is 0.7, the fuel economy under the proposed model predictive control-based strategy can reach more than 92.99% of the fuel economy under the dynamic programming strategy, which is at least 11.78% higher than that under the rule-based strategy. Furthermore, the proposed strategy exhibits better fuel economy as the initial SOC increases.
  • Life Prediction of Supercapacitor Based on Improved Support Vector Regression
    LIU Xiaoming, REN Yupeng, Member, CPSS, CHEN Hai, FENG Dawei, TIAN Jun
    2025, 23(6): 320-328. https://doi.org/10.13234/j.issn.2095-2805.2025.6.320
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The service performance and remaining life of a supercapacitor which serves as a novel energy storage device are part of the factors affecting the operation reliability of a system. A 2.7 V/10 F supercapacitor was taken as the research object, an aging experiment and test platform for energy storage devices was built, and the rules for the performance degradation of the supercapacitor and influencing factors were analyzed by collecting the variations in its characteristics. To solve the contradictory relationship between small samples and prediction accuracy of the supercapacitor lifetime prediction training set, a lifetime prediction method combining the non-dominated sorting genetic algorithm II (NSGA-II) with an elite retention strategy and support vector regression (SVR) was proposed, and the average values of charge-discharge cycles and charge-discharge duration were determined as the characterization of supercapacitor performance degradation. Moreover, a dual-objective model with the minimum sample size and highest prediction accuracy in the training set was established. Compared with the BP(back propagation), SVR and LSTM(long short-term memory) methods, the proposed NSGA-II-SVR method improved the evaluation indicators of root mean square error and mean absolute percentage error by 5 to 10 times in supercapacitor lifetime prediction under the premise of a small sample size of the training set. Finally, a generalization experiment was carried out using the open-source data set of lithium-ion batteries provided by NASA, proving that the NSGA-II-SVR method has strong generalization capability.
    • Power Semiconductor Devices
  • Peak Reverse Recovery Current Model for Freewheeling Diode and Its Application in Junction Temperature Prediction
    JIAO Qianming, ZHU Lingyu, ZHAN Cao, LIU Zhanlei, WANG Weicheng, JI Shengchang
    2025, 23(6): 329-339. https://doi.org/10.13234/j.issn.2095-2805.2025.6.329
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    The accurate chip junction temperature prediction of power semiconductor modules is significant for their reliable operation. However, the research about freewheeling diode (FWD) chip junction temperature prediction is not sufficient at present, and the models of temperature sensitive electric parameters and the corresponding evaluation mechanism are lacking. A peak reverse recovery current model is deduced based on the turn-off process of FWD, and the relationship of peak reverse recovery current with bus voltage, load current and junction temperature is established. Then, a parameter identification approach for the peak reverse recovery current model is proposed based on the particle swarm optimization algorithm with random mutation, and the result of double-pulse test is used to extract the model parameters and verify the model. To reduce the model error caused by the linear distribution and linear changes of carriers, the exponential terms of load current and bus voltage are further added, thus optimizing the prediction of peak current. Finally, a junction temperature prediction approach for FWD chips in power semiconductor modules is put forward based on the optimized model, and this approach is more accurate compared with the look-up-table method, indicating that it can satisfy the requirements of FWD junction temperature prediction.
  • Research on Improved Online Dead-time Compensation Method for GaN HEMT Power Devices
    GAO Yunxiang, Member, CPSS, LIU Wei, HUANG Shan, WANG Xiaohong, JIANG Tinghao
    2025, 23(6): 340-352. https://doi.org/10.13234/j.issn.2095-2805.2025.6.340
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    To ensure the safe and reliable operation of a three-phase bridge leg, it is necessary to set a reasonable dead-time. Due to its own characteristics, the voltage variation in the dead-time of a gallium nitride high-electron mobility transistor (GaN HEMT) is different from those of traditional Si devices. In this paper, the problem of large reverse conduction voltage drops in GaN HEMT power devices is analyzed, and an improved online dead-time compensation method based on GaN HEMT power devices is proposed. This method can not only avoid the influence of circuit noise on the judgment of current direction, but also reduce the phase voltage error and current harmonics, thus improving the circuit stability. Finally, the effectiveness of the improved online dead-time compensation method was verified by simulation experiments and the construction of an experimental platform, indicating that it has obvious advantages over the traditional dead-time compensation method under the condition of large reverse conduction voltage drops.
Volume 23 Issue 6
30 October 2025
Supervised by:
China Association for Science and Technology
Sponsored by:
China Power Supply Society
National Ocean Technology Center
Edited by: Editorial Department of JOURNAL OF POWER SUPPLY
Distribution in China: Local Post Offices or Online subscription
Editor-in-Chief: Jiaxin Han
Acting Editor-in-Chief: Xinbo Ruan
Co-Editor-in-Chief: Xiong Du and Wu Chen
Editorial Manager: Guozhen Chen
CN: 12-1420/TM
ISSN: 2095-2805
Postal Code in China: 6-273
International Postal Code: BM8665
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