|
|
|
| Modular Multi-Port Converter Voltage Balancing Topology and Voltage Matching Control for Battery-Swapping Stations |
| Huang Yanhui1, Li Rui2, Liu Fei1, Hu Shili1, Wu Yao1 |
1. School of Electrical Engineering and Automation Wuhan University Wuhan 430072 China;
2. Wuhan Second Ship Design and Research Institute Wuhan 430010 China |
|
|
|
Abstract Battery-swapping stations offer an alternative charging service, significantly reducing charging duration. As the number and charging power of electric vehicles continue to rise, these stations require connection to a medium-voltage grid to expand capacity. However, the traditional solution entails numerous converters and two power conversion stages, resulting in significant device costs and power loss. This paper proposes a single-stage modular multi-port converter with voltage balancing for Battery-Swapping Stations. By integrating just one power converter stage, this approach effectively lowers equipment costs and minimizes power losses. Additionally, a voltage balancing circuit and a voltage matching (VM) control strategy are proposed to address power mismatch issues arising from state-of-charge differences.
The sub-module utilizes a phase-shifted full-bridge (PSFB) configuration to regulate charging power by adjusting the phase-shift angle of the drive signals between the two main bridge arms. The input side of the PSFB is linked in series to the MVDC bus, while the output side serves as a distinct charging port for connecting to the power battery. This configuration ensures only one power conversion stage from the MVDC bus to the charging port. This paper introduces LC balance branches at the input side of adjacent modules to solve series voltage mismatch, thereby conserving active devices. Mismatched power transfers between two sub-modules while the PSFB ensures continuous battery charging. The two switches of the leading leg of each submodule are multiplexed and continue to operate in the zero-voltage switching (ZVS) state. Furthermore, this paper proposes a voltage matching (VM) control strategy. Based on the battery voltage, the corresponding input voltage of each module is adjusted proportionally, aligning more closely with the battery voltage. Compared to traditional voltage equalization control methods, this approach broadens the charging voltage range of the converter and reduces battery charging current ripples.
Simulation results demonstrate that the converter output current consistently aligns with the reference value, even when the reference value changes. When the port voltages of batteries 1 to 5 are 650, 700, 800, 850, and 900 V, respectively, the submodule effectively maintains input voltages at 833, 897, 1 026, 1 090, and 1 154 V through the VM control. Notably, the VM control successfully charges the 970 V battery, a task unachievable with traditional voltage equalization control due to insufficient power output. When concurrently charging a 600 V battery, the current ripple reduces from 5.5 A with the conventional control to 3.3 A with the VM control. The experimental results demonstrate that the switches can still operate in the ZVS state.
The following conclusions can be drawn. The proposed LC voltage balance structure eliminates the need for additional switches, thereby reducing hardware costs. With only one stage of power conversion and switches capable of ZVS, the converter enhances efficiency. By controlling both the intra-module and inter-module phase-shift angles of the converter, battery charging control and submodule VM control can be realized simultaneously. The proposed VM control strategy makes the input voltage match the battery voltage, thereby broadening the charging voltage range of the converter and reducing battery charging current ripples.
With the VM control, each module's input voltage reference value is proportionally distributed based on the battery voltage, which has a rather simplistic selection process. Future research will focus on the flexible voltage reference selection for each port.
|
|
Received: 04 January 2024
|
|
|
|
|
|
[1] 姜欣, 冯永涛, 熊虎, 等. 基于出行概率矩阵的电动汽车充电站规划[J]. 电工技术学报, 2019, 34(增刊1): 272-281.
Jiang Xin, Feng Yongtao, Xiong Hu, et al.Planning of electric vehicle charging station based on travel probability matrix[J]. Transactions of China Elec- trotechnical Society, 2019, 34(S1): 272-281.
[2] 刘征宇, 郭乐凯, 孟辉, 等. 基于改进DBSCAN的退役动力电池分选方法[J]. 电工技术学报, 2023, 38(11): 3073-3083.
Liu Zhengyu, Guo Lekai, Meng Hui, et al.A sorting method of retired power battery based on improved DBSCAN[J]. Transactions of China Electrotechnical Society, 2023, 38(11): 3073-3083.
[3] 崔刚, 熊斌, 黄康杰, 等. 电动汽车用永磁电机的失磁空间分布特性及影响因素[J]. 电工技术学报, 2023, 38(22): 5959-5974.
Cui Gang, Xiong Bin, Huang Kangjie, et al.Spatial distribution characteristics and influencing factors of demagnetization of permanent magnet motor for electric vehicle[J]. Transactions of China Electro- technical Society, 2023, 38(22): 5959-5974.
[4] 吴巨爱, 薛禹胜, 谢东亮, 等. 电动汽车参与电量市场与备用市场的联合风险调度[J]. 电工技术学报, 2023, 38(23): 6407-6418.
Wu Juai, Xue Yusheng, Xie Dongliang, et al.The joint risk dispatch of electric vehicle in day-ahead electricity energy market and reserve market[J]. Transactions of China Electrotechnical Society, 2023, 38(23): 6407-6418.
[5] 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.
[6] 刘灵恺, 雷霞, 李竹, 等. 电动汽车换电站可用电池组数动态调度策略[J]. 电工技术学报, 2017, 32(22): 242-250.
Liu Lingkai, Lei Xia, Li Zhu, et al.Dynamic scheduling strategy for available battery number of electric vehicle in battery-swap station[J]. Transa- ctions of China Electrotechnical Society, 2017, 32(22): 242-250.
[7] 杨景旭, 唐渊, 姚蓝霓, 等. 考虑服务能力和削峰任务约束的换电站削峰方法[J]. 电力系统自动化, 2022, 46(15): 29-36.
Yang Jingxu, Tang Yuan, Yao Lanni, et al.Peak- shaving method for battery swap station considering service capacity and peak-shaving task constraints[J]. Automation of Electric Power Systems, 2022, 46(15): 29-36.
[8] 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.
[9] Xuan Yang, Yang Xu, Chen Wenjie, et al.A novel three-level CLLC resonant DC-DC converter for bidirectional EV charger in DC microgrids[J]. IEEE Transactions on Industrial Electronics, 2021, 68(3): 2334-2344.
[10] 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.
[11] Wu Jiayang, Li Sinan, Tan S C, et al.Capacitor- clamped LLC resonant converter operating in capacitive region for high-power-density EV charger[J]. IEEE Transactions on Power Electronics, 2021, 36(10): 11456-11468.
[12] Iyer V M, Gulur S, Gohil G, et al.An approach towards extreme fast charging station power delivery for electric vehicles with partial power processing[J]. IEEE Transactions on Industrial Electronics, 2020, 67(10): 8076-8087.
[13] 黄海宏, 颜碧琛, 王海欣. 并联级联H桥电源电流跟踪优化与环流抑制的模型预测控制[J]. 电工技术学报, 2023, 38(16): 4376-4390.
Huang Haihong, Yan Bichen, Wang Haixin.Model predictive control of current tracking optimization and circulating current suppression for multi-parallel cascaded H-bridge power supplies[J]. Transactions of China Electrotechnical Society, 2023, 38(16): 4376-4390.
[14] 何晓坤, 胡仁杰, 陈武. 一种适用于新能源中压直流汇集的无环流零电流软开关三电平谐振式复合全桥变换器[J]. 电工技术学报, 2023, 38(19): 5274-5287.
He Xiaokun, Hu Renjie, Chen Wu.A novel circulating current free zero current switching three-level resonant composite full bridge converter for new energy medium voltage DC collection system[J]. Transactions of China Electrotechnical Society, 2023, 38(19): 5274-5287.
[15] Zhao Biao, Song Qiang, Li Jianguo, et al.Full- process operation, control, and experiments of modular high-frequency-link DC transformer based on dual active bridge for flexible MVDC distribution: a practical tutorial[J]. IEEE Transactions on Power Electronics, 2017, 32(9): 6751-6766.
[16] Zhuang Yizhan, Liu Fei, Huang Yanhui, et al.A multiport modular DC-DC converter with low-loss series LC power balancing unit for MVDC interface of distributed photovoltaics[J]. IEEE Transactions on Power Electronics, 2021, 36(7): 7736-7749.
[17] Phung T H, Collet A, Crebier J C.An optimized topology for next-to-next balancing of series- connected lithium-ion cells[J]. IEEE Transactions on Power Electronics, 2014, 29(9): 4603-4613.
[18] 张洋, 丘东元, 张波, 等. DC-DC变换器分层级构造方法[J]. 电工技术学报, 2023, 38(20): 5473-5487.
Zhang Yang, Qiu Dongyuan, Zhang Bo, et al.Hierarchical synthesis methods of DC-DC con- verters[J]. Transactions of China Electrotechnical Society, 2023, 38(20): 5473-5487.
[19] 唐佳维. 基于双向Cuk变换器的电动汽车锂电池组均衡研究[D]. 盐城: 盐城工学院, 2023.
Tang Jiawei.Equalization of lithium battery pack for electric vehicle based on bidirectional Cuk con- verter[D]. Yancheng: Yancheng Institute of Tech- nology, 2023.
[20] 庄一展, 刘飞, 黄艳辉, 等. 模块化串联光伏直流变换器的环形功率均衡拓扑及效率优化策略[J]. 中国电机工程学报, 2022, 42(5): 1657-1668, 2.
Zhuang Yizhan, Liu Fei, Huang Yanhui, et al.A circular power balancing topology with efficiency optimization strategy for modular cascaded photo- voltaic DC/DC converter[J]. Proceedings of the CSEE, 2022, 42(5): 1657-1668, 2.
[21] Mao Meiqin, Ding Yong, Chang Liuchen, et al.Multi-objective power management for EV fleet with MMC-based integration into smart grid[J]. IEEE Transactions on Smart Grid, 2019, 10(2): 1428-1439.
[22] 韩雪, 贺荣栋, 凌志斌. 部分接入电池储能系统的模块化多电平换流器控制方法[J]. 电力系统自动化, 2024, 48(1): 100-108.
Han Xue, He Rongdong, Ling Zhibin.Control method of modular multilevel converter with partly integrated battery energy storage system[J]. Automation of Electric Power Systems, 2024, 48(1): 100-108.
[23] Ma Yajun, Xiao Jianjie, Lin Hua, et al.A novel battery integration method of modular multilevel converter with battery energy storage system for capacitor voltage ripple reduction[J]. IEEE Transa- ctions on Industrial Electronics, 2021, 68(12): 12250-12261.
[24] Zhang Xiangjun, Li Chuanyu, Yang Hua, et al.Control strategy analysis and loop design of full- bridge phase-shift soft-switching DC-DC converter[C]// 2016 IEEE 8th International Power Electronics and Motion Control Conference (IPEMC-ECCE Asia), Hefei, China, 2016: 1139-1145. |
|
|
|
2025, Vol. 40 
