Abstract：This paper proposes a discontinuous current mode resonant converter with pulse width modulation (PWM) control. The fixed-frequency PWM control is employed, and an auxiliary inductor and an auxiliary capacitor are added to the primary side switch network. By adjusting the duty cycle of the drive signal of the primary side switch, the voltage amplitude between the midpoints of the bridge arm can be changed, and then the voltage gain of the converter can be adjusted. The resonant current works in discontinuous mode through a suitable parameter design for the converter, so there is no reactive current. Meanwhile, all switches can realize soft-switching, which reduces the switching loss. This paper first analyzes the working principle and operating modes of the converter. Then, the characteristics of the converter, including the voltage gain, soft-switching conditions, and discontinuous current mode conditions, are deduced, and a parameter design method is proposed. Finally, a 1 000W prototype is built to verify the feasibility of the converter and the correctness of the theoretical analysis.
[1] 王议锋, 陈博, 吕雯, 等. 拓扑变换型LLC-C谐振软开关直流变换器[J]. 电工技术学报, 2019, 34(18): 3810-3820. Wang Yifeng, Chen Bo, Lü Wen, et al.A topology morphing LLC-C resonant soft-switching DC-DC converter[J]. Transactions of China Electrotechnical Society, 2019, 34(18): 3810-3820. [2] 倪梦涵, 杨晓峰, 王淼, 等. 多电平均压型直流变换器输入电流纹波抑制策略[J]. 电工技术学报, 2021, 36(16): 3354-3364. Ni Menghan, Yang Xiaofeng, Wang Miao, et al.Input current ripple suppression strategy of multilevel voltage-balancing DC-DC converter[J]. Transactions of China Electrotechnical Society, 2021, 36(16): 3354-3364. [3] 赵子先, 康龙云, 于玮, 等. 基于简化时域模型的CLLC直流变换器参数设计[J]. 电工技术学报, 2022, 37(5): 1262-1274. Zhao Zixian, Kang Longyun, Yu Wei, et al.Parameter design method of CLLC DC-DC converter based on simplified time domain model[J]. Transactions of China Electrotechnical Society, 2022, 37(5): 1262-1274. [4] 杨晨, 谢少军, 毛玲, 等. 高输入电压双管Buck- Boost变换器控制策略研究[J]. 电工技术学报, 2014, 29(4): 70-78. Yang Chen, Xie Shaojun, Mao Ling, et al.Research on control strategy of two-switch Buck-Boost con- verter for high voltage application[J]. Transactions of China Electrotechnical Society, 2014, 29(4): 70-78. [5] 张海亮, 刘树林, 王航杰, 等. 一种新型二次侧自复位正激变换器研究[J/OL]. 电工技术学报: 1-7 [2022-05-26]. DOI: 10.19595/j.cnki.1000-6753.tces. 191581. Zhang Hailiang, Liu Shulin, Wang Hangjie, et al.Research on a new forward converter with self- magnetically reset on the secondary side[J/OL]. Transactions of China Electrotechnical Society, 1-7 [2022-05-26]. DOI: 10.19595/j.cnki.1000-6753.tces. 191581. [6] 赵进. 高频谐振变换器的设计和控制关键技术研究[D]. 南京: 东南大学, 2021. [7] 王泽景, 王颖, 龚春英. 高降压比LLC谐振型直流变压器[J]. 电工技术学报, 2015, 30(14): 193-200. Wang Zejing, Wang Ying, Gong Chunying.High step-down LLC resonant DC-DC transformer[J]. Transactions of China Electrotechnical Society, 2015, 30(14): 193-200. [8] 丁超, 李勇, 姜利, 等. 电动汽车直流充电系统LLC谐振变换器软开关电压边界分析[J]. 电工技术学报, 2022, 37(1): 3-11. Ding Chao, Li Yong, Jiang Li, et al.Analysis of soft switching voltage boundary of LLC resonant con- verter for EV DC charging system[J]. Transactions of China Electrotechnical Society, 2022, 37(1): 3-11. [9] Li Bin, Li Qiang, Lee F C.High-frequency PCB winding transformer with integrated inductors for a bi-directional resonant converter[J]. IEEE Transa- ctions on Power Electronics, 2019, 34(7): 6123-6135. [10] 刘博林, 张晓冬, 李越, 等. 应用于电动汽车充电的变频-移相控制方法LLC谐振变换器[J]. 电源学报, 2020, 18(5): 43-52. Liu Bolin, Zhang Xiaodong, Li Yue, et al.Variable frequency-phase shift control method for LLC reso- nant converter applied to electric vehicle charging[J]. Journal of Power Supply, 2020, 18(5): 43-52. [11] 李小双, 田钦元, 王正仕. 基于变频与副边移相控制的双向LLC谐振变换器[J]. 电工技术, 2021(21): 83-86, 96. Li Xiaoshuang, Tian Qinyuan, Wang Zhengshi.Bidirectional LLC resonant converter based on frequency conversion and secondary-side phase shift control[J]. Electric Engineering, 2021(21): 83-86, 96. [12] 石健将, 章江铭, 龙江涛, 等. 高频变压器一次侧串联LLC+输出端并联Buck级联直流变换器[J]. 电工技术学报, 2015, 30(24): 93-102. Shi Jianjiang, Zhang Jiangming, Long Jiangtao, et al.A cascaded DC converter with primary series trans- former LLC and output interleaved Buck[J]. Transa- ctions of China Electrotechnical Society, 2015, 30(24): 93-102. [13] 孙孝峰, 仇江峰, 栗晓华, 等. 一种具有宽输入电压范围的集成Buck-Boost LLC级联变换器[J]. 中国电机工程学报, 2016, 36(6): 1667-1673. Sun Xiaofeng, Qiu Jiangfeng, Li Xiaohua, et al.An integrated Buck-Boost LLC cascaded converter with wide input voltage range[J]. Proceedings of the CSEE, 2016, 36(6): 1667-1673. [14] Ahmed M H, Fei Chao, Lee F C, et al.Single-stage high-efficiency 48/1V sigma converter with inte- grated magnetics[J]. IEEE Transactions on Industrial Electronics, 2020, 67(1): 192-202. [15] Wu Zongheng, Wang Zhiwei, Zhang Yi, et al.A high efficiency and high power density DC transformer topology with output regulation capability[J]. IEEE Transactions on Power Electronics, 2022, 37(7): 8232-8247. [16] Liao Yuefeng, Xu Guo, Peng Tao, et al.An LLC- DAB bidirectional DCX converter with wide load range ZVS and reduced switch count[J]. IEEE Transa- ctions on Power Electronics, 2022, 37(2): 2250-2263. [17] Liu Tianji, Wu Xinke, Yang Shu.1MHz 48-12V regulated DCX with single transformer[J]. IEEE Journal of Emerging and Selected Topics in Power Electronics, 2021, 9(1): 38-47.
2022, Vol. 37 
