Abstract：In recent years, the market share of electric vehicles has been expanding. The development of on-board charger (OBC) provides an efficient, convenient and safe charging solution for electric vehicles. With the improvement of charging technology and the increase of vehicle battery capacity, the optimal design of OBC has become an important link in the electric vehicle industry chain. Aiming at the four major challenges of OBC technology: high power density, high efficiency, wide voltage gain, and multi-function, this paper focuses on the key issue of “wide voltage gain”, and explores how to achieve a wider voltage gain range to improve charging efficiency and flexibility. Based on the comparison and analysis of the existing OBC topologies and its functional characteristics, this paper investigates a new bidirectional two-stage isolated topology, including a front-end bidirectional AC-DC converter and a back-end bidirectional DC-DC converter. The front stage is composed of a single-phase PWM rectifier and a Sepic-Zeta DC-DC converter, and the back stage is a bidirectional CLLLC resonant converter. The proposed topology can effectively adapt to the charging requirements under different battery voltage levels while ensuring bidirectional energy flow. The following section will focus on the analysis of the back-end bidirectional CLLLC resonant converter. As a critical component of the overall topology, the design of this converter is aimed at ensuring high-efficiency power conversion across a wide range of loads. The bidirectional CLLLC converter can achieve high-efficiency power conversion over a wide range of loads. The voltage gain model of the CLLLC resonant converter, established using the fundamental harmonic approximation (FHA) method, can be utilized to analyze the characteristics or design parameters of the CLLLC resonant converter. Based on the gain characteristic curves, the impact of the DC bus voltage on the operating point is analyzed. Consequently, by adopting variable DC bus voltage control, the range of switching frequency variation can be significantly reduced while ensuring a wide range of output voltages. To address the issues of low efficiency in buck-type with pulse frequency modulation (PFM) and high return power and narrow gain in single phase shift (SPS) modulation in the bidirectional CLLLC resonant converter, a segmented hybrid modulation strategy combining “Frequency conversion+Extended Phase Shift” has been investigated. When M≥1, PFM is employed to control the output power efficiently, while extended phase shift (EPS) modulation is utilized when M<1. The conditions for achieving zero-voltage switching (ZVS) under EPS modulation are analyzed. Combined with the variable DC bus voltage control strategy, this approach significantly reduces the range of switching frequency variation, extends the output voltage range, and achieves the objectives of wide voltage gain and high-efficiency control. Finally, the proposed topology and control strategy were simulated and verified in Matlab/Simulink software, and the software and hardware design of OBC were completed. Based on the STM32H750VBT6 controller, a 6.6 kW OBC experimental platform was built for experimental verification. From the experimental results, it is evident that the control strategy exhibits strong robustness against disturbances, achieving a wide output voltage range from 250 V to 750 V. Both forward and reverse operations enable soft switching across the entire gain range, meeting the anticipated control objectives. The segmented hybrid modulation strategy further enhances the overall efficiency of the system.
王建渊, 郭俊玲, 闫瑾, 孙向东. 基于CLLLC变频扩展移相分段调制的宽增益车载充电机研究[J]. 电工技术学报, 2025, 40(18): 5998-6013.
Wang Jianyuan, Guo Junling, Yan Jin, Sun Xiangdong. Research on Wide Gain Vehicle Charger Based on CLLLC Frequency Conversion Extended Phase Shift Segment Modulation. Transactions of China Electrotechnical Society, 2025, 40(18): 5998-6013.
[1] Wouters H, Martinez W.Bidirectional onboard chargers for electric vehicles: state-of-the-art and future trends[J]. IEEE Transactions on Power Elec-tronics, 2024, 39(1): 693-716. [2] 王晓姬, 王道涵, 王柄东, 等. 电动汽车驱动/充电一体化系统及其控制策略综述[J]. 电工技术学报, 2023, 38(22): 5940-5958. Wang Xiaoji, Wang Daohan, Wang Bingdong, et al.A review of drive-charging integrated systems and control strategies for electric vehicles[J]. Transa-ctions of China Electrotechnical Society, 2023, 38(22): 5940-5958. [3] Lipu M S H, Faisal M, Ansari S, et al. Review of electric vehicle converter configurations, control schemes and optimizations: challenges and sug-gestions[J]. Electronics, 2021, 10(4): 477. [4] Safayatullah M, Elrais M T, Ghosh S, et al.A comprehensive review of power converter topologies and control methods for electric vehicle fast charging applications[J]. IEEE Access, 2022, 10: 40753-40793. [5] Ta L A D, Dao N D, Lee D C. High-efficiency hybrid LLC resonant converter for on-board chargers of plug-in electric vehicles[J]. IEEE Transactions on Power Electronics, 2020, 35(8): 8324-8334. [6] Manickam V K, Dhayalini K.Hybrid optimized control of bidirectional off-board electric vehicle battery charger integrated with vehicle-to-grid[J]. Journal of Energy Storage, 2024, 86: 111008. [7] 汪治, 於锋, 朱志豪. 低电压纹波单相电驱重构型车载充电机研究[J]. 电源学报, 2025, 23(1): 59-66. Wang Zhi, Yu Feng, Zhu Zhihao.Single-phase electric drive reconstructed onboard charger with low voltage ripple[J]. Journal of Power Supply, 2025, 23(1): 59-66. [8] 吴维鑫, 张钟艺, 肖晓森, 等. 基于时域分析的CLLC谐振变换器参数优化设计[J]. 电力系统保护与控制, 2023, 51(14): 139-151. Wu Weixin, Zhang Zhongyi, Xiao Xiaosen, et al.Parameter optimization design of a CLLC resonant converter based on time domain analysis[J]. Power System Protection and Control, 2023, 51(14): 139-151. [9] Wang Yadong, Zhao Wencheng, Liu Bangyin, et al.Optimal design of resonant network for resonant converter[J]. IEEE Transactions on Industry Appli-cations, 2022, 58(6): 7469-7478. [10] 王翌琛, 王丰, 卓放, 等. 基于过谐振调频扩展移相控制的CLLC谐振变换器电流优化策略[J]. 电力系统自动化, 2025, 49(3): 178-188. Wang Yichen, Wang Feng, Zhuo Fang, et al.Current optimization strategy for CLLC resonant converter based on over-resonant frequency modulation and extended phase-shift control[J]. Power System Pro-tection and Control, 2025, 49(3): 178-188. [11] Zhang Xiangjun, Tang Weiming, Liu Hao, et al.Design and modeling of CLLC converter for bidirectional on-board charger[J]. IEEE Transactions on Industry Applications, 2023, 59(5): 6095-6102. [12] Li Xiaoqiang, Huang Jinwei, Ma Yongchao, et al.Unified modeling, analysis, and design of isolated bidirectional CLLC resonant DC-DC converters[J]. IEEE Journal of Emerging and Selected Topics in Power Electronics, 2022, 10(2): 2305-2318. [13] 李小双, 田钦元, 王正仕. 双向CLLLC谐振变换器的混合控制策略[J]. 电力电子技术, 2022, 56(6): 111-114, 140. Li Xiaoshuang, Tian Qinyuan, Wang Zhengshi.Hybrid control strategy of bidirectional CLLLC resonant converter[J]. Power Electronics, 2022, 56(6): 111-114, 140. [14] Xue Bo, Wang Haoyu, Liang Junrui, et al.Phase-shift modulated interleaved LLC converter with ultrawide output voltage range[J]. IEEE Transactions on Power Electronics, 2021, 36(1): 493-503. [15] Tang Xinxi, Xing Yan, Wu Hongfei, et al.An improved LLC resonant converter with reconfigurable hybrid voltage multiplier and PWM-plus-PFM hybrid control for wide output range applications[J]. IEEE Transactions on Power Electronics, 2020, 35(1): 185-197. [16] 周国华, 王淇, 邓伦博. 宽增益高效率CLLLC变换器的变频双移相调制策略[J]. 电工技术学报, 2024, 39(8): 2511-2522. Zhou Guohua, Wang Qi, Deng Lunbo.Frequency conversion and double phase shift modulation strategy for wide gain and high efficiency CLLLC converter[J]. Transactions of China Electrotechnical Society, 2024, 39(8): 2511-2522. [17] 邓钦瑞, 何英杰, 雷超, 等. CLLLC谐振变换器变频移相混合控制方法[J]. 电力自动化设备, 2022, 42(2): 148-154. Deng Qinrui, He Yingjie, Lei Chao, et al.PFM+PSM hybrid control of CLLLC resonant converter[J]. Electric Power Automation Equipment, 2022, 42(2): 148-154. [18] Farias Martins L, Stone D, Foster M.Modelling of phase-shift modulated bidirectional CLLC resonant converter[J]. IET Power Electronics, 2020, 13(12): 2628-2637. [19] Zhu Tianhua, Zhuo Fang, Zhao Fangzhou, et al.Optimization of extended phase-shift control for full-bridge CLLC resonant converter with improved light-load efficiency[J]. IEEE Transactions on Power Electronics, 2020, 35(10): 11129-11142. [20] Meinagh F A A, Min J, Ordonez M, et al. Improved triple-phase-shift modulation for bidirectional CLLC converters[J]. IEEE Transactions on Power Elec-tronics, 2023, 38(6): 7348-7361. [21] Chen Huan, Wang Leheng, Sun Kai, et al.A switching delay strategy for sensorless synchronous rectification in CLLC converters[J]. IEEE Transa-ctions on Power Electronics, 2024, 39(1): 280-293. [22] 徐菁涛, 许国, 孙尧, 等. 耦合电感集成型谐振变换器及其自适应频率控制[J]. 电工技术学报, 2023, 38(4): 998-1009. Xu Jingtao, Xu Guo, Sun Yao, et al.Coupled inductor integrated resonant converter with adaptive frequency control[J]. Transactions of China Electrotechnical Society, 2023, 38(4): 998-1009. [23] 黄何伟, 曹太强, 潘光绪, 等. 考虑回流功率因素的全桥CLL谐振变换器参数优化设计[J]. 电工技术学报, 2023, 38(20): 5503-5514. Huang Hewei, Cao Taiqiang, Pan Guangxu, et al.Parameter optimal design of full-bridge CLL resonant converter considering backflow power factor[J]. Transactions of China Electrotechnical Society, 2023, 38(20): 5503-5514. [24] 高祎韩, 周子航, 张欣, 等. 双有源桥串联欠谐振变换器的最小回流电流控制[J]. 电工技术学报, 2024, 39(14): 4480-4494. Gao Yihan, Zhou Zihang, Zhang Xin, et al.Minimum backflow current control of under-resonant-dual-bridge-series-resonant converter[J]. Transactions of China Electrotechnical Society, 2024, 39(14): 4480-4494. [25] 陈庆华, 吴克, 邱荣禄, 等. 一种具有高容错能力的改进型LLC拓扑及其控制策略[J]. 电源学报, 2024, 22(3): 165-171. Chen Qinghua, Wu Ke, Qiu Ronglu, et al.Improved LLC topology with high fault tolerance capability and its control strategy[J]. Journal of Power Supply, 2024, 22(3): 165-171.
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