Abstract：The dual-active half-bridge (DAHB) converter has the advantages of high-frequency galvanic isolation, symmetric topology, and soft-switching. It has few power devices, low count, and no dc offset current, suitable for low-power dc-dc power conversion applications. In the case of renewable energy and energy storage equipment access, the DAHB converter operates in a broad input and output voltage range, where the rough traditional single-phase shift control (SPC) strategy usually leads to high current stress and power loss. Existing DAHB multi-phase shift control has problems like inaccurate capacitor voltage calculation, complicated control algorithm, and large computational quantity. Therefore, this paper presents a three-degree freedom control (TFC) strategy based on PWM plus phase-shift concepts. Firstly, according to the operation mechanism of the DAHB converter, the equivalent circuit is established considering the coupling relationship between the primary and secondary sides of the transformer. The accurate expression of the series capacitor voltage is derived from the voltage-second balance of inductance L and the charge balance of capacitors in the charge and discharge process. The capacitor voltage of each bridge arm is related to the transformer turn ratio n, duty cycle d1d2, input and output voltage U1U2, and capacitance value CpCs. Secondly, based on the principle of PWM and phase-shift control, 18 possible switching modes of DAHB in a wide voltage range are listed, with three control degrees of freedom (phase shift df, primary- and secondary-side duty cycles d1d2) as variables. The optimal switching mode is chosen for minimum reactive power, and the analytical expressions of key electrical parameters are derived. Thirdly, according to the Karush-Kuhn-Tucker (KKT) method, the local optimal equation containing equality and inequality constraints is established to solve the optimal control strategy. This paper adopts model simplification and linear approximation methods to solve complicated optimal equations. Using MATLAB’s ‘fmincon’ function, the optimal combination of duty cycles and phase shifts in different working conditions is obtained. Then, drawing duty cycle change curves with phase shifts under different powers, the linear fitting between d2 and df is carried out. According to the current waveform characteristics, the constraint relationship between d1 and d2 df is analyzed. Thus, the analytical expression of the TFC strategy under boost and buck conditions is obtained. The optimal control strategy of the DAHB converter in the full power range consists of SPS and TFC strategies. Finally, the optimization effect and soft switching characteristics of the TFC are analyzed by PLECS simulation and a 400 W DAHB converter experiment platform. The following conclusions can be drawn from simulation and experimental results: (1) The capacitor voltage calculation formula can accurately calculate the capacitor voltage of the DAHB bridge arm in various working conditions. The error is verified by simulation within 0.1%. (2) Compared with existing SPC and other dual-degree freedom control strategies, the proposed TFC strategy reduces the current stress and power loss of the DAHB under voltage mismatch, especially in light load. (3) The proposed strategy reduces the number of PI regulators, which is easy to implement in engineering.
任强, 康薇, 姜亚鹏, 秦祝. 基于PWM+移相的双有源半桥DC-DC变换器分析及其控制[J]. 电工技术学报, 2024, 39(15): 4830-4842.
Ren Qiang, Kang Wei, Jiang Yapeng, Qin Zhu. Analysis and Control of Dual-Active Half-Bridge DC-DC Converter with PWM Plus Phase Shift. Transactions of China Electrotechnical Society, 2024, 39(15): 4830-4842.
[1] 刘计龙, 陈鹏, 肖飞, 等. 面向舰船综合电力系统的10 kV/2 MW模块化多电平双向直流变换器控制策略[J]. 电工技术学报, 2023, 38(4): 983-997. Liu Jilong, Chen Peng, Xiao Fei, et al.Control strategy of 10 kV/2 MW modular multilevel bidire- ctional DC-DC converter for vessel integrated power system[J]. Transactions of China Electrotechnical Society, 2023, 38(4): 983-997. [2] 杨向真, 王锦秀, 孔令浩, 等. 电压不匹配运行条件下双有源桥变换器的效率优化方法[J]. 电工技术学报, 2022, 37(24): 6239-6251. Yang Xiangzhen, Wang Jinxiu, Kong Linghao, et al.Efficiency optimization method of DAB converters under wide-voltage operating conditions[J]. Transa- ctions of China Electrotechnical Society, 2022, 37(24): 6239-6251. [3] 任强, 艾胜. 全工况范围的DAB三自由度优化控制策略[J]. 中国电机工程学报, 2020, 40(11): 3613-3622. Ren Qiang, Ai Sheng.A three degree freedom optimal control strategy of dual-active-bridge converters for full range operations[J]. Proceedings of the CSEE, 2020, 40(11): 3613-3622. [4] 熊飞, 吴俊勇, 郝亮亮, 等. 隔离型双半桥DC-DC变换器的软开关特性[J]. 电工技术学报, 2017, 32(10): 196-205, 221. Xiong Fei, Wu Junyong, Hao Liangliang, et al.Soft switching characteristics of the dual-half-bridge DC- DC converter[J]. Transactions of China Electrotech- nical Society, 2017, 32(10): 196-205, 221. [5] Kang Xiangli, Li Shouxiang, Smedley K M.Decoupled PWM plus phase-shift control for a dual- half-bridge bidirectional DC-DC converter[J]. IEEE Transactions on Power Electronics, 2018, 33(8): 7203-7213. [6] Gao Fei, Mugwisi N, Rogers D J.Average modeling of a dual-half-bridge converter modulated with three degrees of freedom[J]. IEEE Transactions on Transpo- rtation Electrification, 2021, 7(3): 1016-1030. [7] Zhao Biao, Song Qiang, Liu Wenhua, et al.Overview of dual-active-bridge isolated bidirectional DC-DC converter for high-frequency-link power-conversion system[J]. IEEE Transactions on Power Electronics, 2014, 29(8): 4091-4106. [8] 吴俊娟, 孟德越, 申彦峰, 等. 双重移相控制与传统移相控制相结合的双有源桥式DC-DC变换器优化控制策略[J]. 电工技术学报, 2016, 31(19): 97-105. Wu Junjuan, Meng Deyue, Shen Yanfeng, et al.Optimal control strategy of dual active bridge DC-DC converter with combined dual-phase-shift and traditional-phase-shift controls[J]. Transactions of China Electrotechnical Society, 2016, 31(19): 97-105 [9] Chakraborty S, Chattopadhyay S.Analysis and com- parison of voltage-source and current-source asymme- tric dual-active half-bridge converters[C]//2014 IEEE Energy Conversion Congress and Exposition (ECCE), Pittsburgh, PA, USA, 2014: 2072-2079. [10] Gao Fei, Rogers D.Duty-cycle plus phase-shift control for a dual active half bridge based bipolar DC microgrid[C]//2018 IEEE Applied Power Electronics Conference and Exposition (APEC), San Antonio, TX, USA, 2018: 1479-1485. [11] 胡广, 胡维昊, 唐远鸿, 等. 基于强化学习的双主动半桥直流变换器的效率优化方案[J]. 电工技术学报, 2022, 37(增刊1): 225-234. Hu Guang, Hu Weihao, Tang Yuanhong, et al.Efficiency optimization scheme of dual-active-half- bridge DC-DC converter based on reinforcement learning[J]. Transactions of China Electrotechnical Society, 2022, 37(S1): 225-234. [12] Chakraborty S, Chattopadhyay S.Minimum-RMS- current operation of asymmetric dual active half- bridge converters with and without ZVS[J]. IEEE Transactions on Power Electronics, 2017, 32(7): 5132-5145. [13] Chakraborty S, Tripathy S, Chattopadhyay S.Mini- mum RMS current operation of the dual-active half- bridge converter using three degree of freedom control[C]//2016 IEEE Energy Conversion Congress and Exposition (ECCE), Milwaukee, WI, USA, 2017: 1-8. [14] Chakraborty S, Chattopadhyay S.Fully ZVS, mini- mum RMS current operation of the dual-active half-bridge converter using closed-loop three-degree- of-freedom control[J]. IEEE Transactions on Power Electronics, 2018, 33(12): 10188-10199. [15] Zhao Shuang, Umuhoza J, Zhang Yuzhi, et al.Analysis and optimization of a high-efficiency resi- dential energy harvesting system with dual half- bridge converter[C]//2017 IEEE Applied Power Electronics Conference and Exposition (APEC), Tampa, FL, USA, 2017: 2838-2844. [16] He Peiwen, Khaligh A.Comprehensive analyses and comparison of 1 kW isolated DC-DC converters for bidirectional EV charging systems[J]. IEEE Transa- ctions on Transportation Electrification, 2017, 3(1): 147-156. [17] Chakraborty S, Palmal M, Chattopadhyay S.Appro- aches for continuous-time dynamic modeling of the asymmetric dual-active half-bridge converter[C]// 2018 IEEE Applied Power Electronics Conference and Exposition (APEC), San Antonio, TX, USA, 2018: 952-958. [18] Tissières M, Askarian I, Pahlevani M, et al.A digital robust control scheme for dual half-bridge DC-DC converters[C]//2018 IEEE Applied Power Electronics Conference and Exposition (APEC), San Antonio, TX, USA, 2018: 311-315. [19] 侯旭, 曾正, 冉立, 等. 基于扩展移相控制的双向有源桥变换器回流功率优化[J]. 中国电机工程学报, 2018, 38(23): 7004-7014, 7134. Hou Xu, Zeng Zheng, Ran Li, et al.Backflow power optimization of dual active bridge converter based on extended-phase-shift control[J]. Proceedings of the CSEE, 2018, 38(23): 7004-7014, 7134. [20] Lin Nan, Zhao Zhe, Diao Fei, et al.A current-fed dual-half-bridge-based composite converter with improved light-load efficiency through a multi- variable optimization[J]. IEEE Transactions on Trans- portation Electrification, 2022, 8(2): 3008-3020. [21] Li Haoyu, Zhao Lei, Xu Chuanyu, et al.A dual half-bridge phase-shifted converter with wide ZVZCS switching range[J]. IEEE Transactions on Power Electronics, 2018, 33(4): 2976-2985. [22] 侯旭, 曾正, 冉立, 等. 基于扩展移相控制的双向有源桥变换器回流功率优化[J]. 中国电机工程学报, 2018, 38(23): 7004-7014, 7134. Hou Xu, Zeng Zheng, Ran Li, et al.Backflow power optimization of dual active bridge converter based on extended-phase-shift control[J]. Proceedings of the CSEE, 2018, 38(23): 7004-7014, 7134.
2024, Vol. 39 
