Abstract:The use of modular series-parallel systems is widespread across numerous fields owing to their capacity to scale up voltage, current, and power output in power systems. Redundancy is an effective method to improve the reliability of IPOS power systems, which are widely used in high-output voltage situations. However, traditional redundancy strategies result in a substantial increase in both cost and volume due to the doubling of power units. This paper proposes a circuit design with low redundancy, high reliability, and ultra-wide voltage range, which empowers IPOS power systems with module-level and system-level redundancy capabilities. Module-level redundancy and system-level N+X redundancy have been achieved through sub-circuit redundancy design at the module level. The full bridge LLC is decomposed into a dual half bridge structure with an input parallel on the primary side of the circuit. The basic unit of the system is established using the half-bridge circuit, and only an additional half-bridge resonant circuit unit is required to achieve redundant backup of the primary side full bridge switching network. This approach effectively reduces redundant units while providing module-level redundant power supply capability. The IPOS system is equipped with multiple power modules, and the redundant circuit units of other modules can replace any malfunctioning power module, providing system-level redundancy capability. As a result, there is no need to set up redundant power modules at the system level, and the power system maintains full voltage range and output power capability even in case of any power module failure. Furthermore, the modulation strategy using carrier stacking technology has been designed to facilitate the rapid and convenient output of redundant units during fault conditions while ensuring the efficient operation of modules. A novel distributed-centralized hybrid control strategy for modular power supply systems is proposed. The proposed strategy leverages distributed autonomous and centralized control mechanisms to prevent module stress imbalance and maintain a target output voltage range. Droop control allows for distributed autonomous control of the power system, thereby eliminating the need for a centralized controller to maintain output voltage within the prescribed range. It ensures balanced output voltage across all modules, improving the system's scalability and fault redundancy. However, droop control alone may compromise the accuracy of the system's total output voltage. Therefore, a low-bandwidth communication control strategy is implemented. The adjustment bandwidth of the upper controller is lowered, and the control loop of each module is preserved. The upper controller analyses the total output voltage and generates voltage references for each module to adjust and correct the total output voltage accurately. Overall, the proposed strategy improves the performance and reliability of modular power supply systems. The principle, characteristics, and implementation scheme of the proposed circuit structure and control strategy have been analyzed. Through experiments on a 0~1 000 V/50 kW output power supply system, the effectiveness of the proposed scheme is verified.
宋猛, 吴红飞, 吴嘉昊, 贾益行, 徐鑫雨. 低冗余高可靠模块化输入并联输出串联电源系统及其控制方法[J]. 电工技术学报, 2024, 39(6): 1898-1906.
Song Meng, Wu Hongfei, Wu Jiahao, Jia Yihang, Xu Xinyu. Low Redundancy High Reliability Modular Input-Parallel Output-Series Power System and Control Method. Transactions of China Electrotechnical Society, 2024, 39(6): 1898-1906.
[1] 朱天宇, 纪延超, 王建赜. 一种高效率的宽输出电压范围LLSC谐振变换器及其控制方法[J]. 电工技术学报, 2022, 37(18): 4697-4706. Zhu Tianyu, Ji Yanchao, Wang Jianze.A high effi- ciency and wide gain range LLSC resonant converter and its control method[J]. Transactions of China Electrotechnical Society, 2022, 37(18): 4697-4706. [2] Fang Tianzhi, Shen Le, He Wei, et al.Distributed control and redundant technique to achieve superior reliability for fully modular input-series-output- parallel inverter system[J]. IEEE Transactions on Power Electronics, 2017, 32(1): 723-735. [3] 赵楠, 郑泽东, 刘建伟, 等. 级联H桥变换器IGBT开路故障分析与冗余方法研究[J]. 电工技术学报, 2023, 38(6): 1608-1619. Zhao Nan, Zheng Zedong, Liu Jianwei, et al.IGBT open-circuit fault analysis and fault-tolerant method for cascaded H-bridge converter[J]. Transactions of China Electrotechnical Society, 2023, 38(6): 1608-1619. [4] 张航, 李子欣, 高范强, 等. 一种混合模块型直流变压器冗余设计及控制策略[J]. 电工技术学报, 2022, 37(2): 409-423. Zhang Hang, Li Zixin, Gao Fanqiang, et al.A redundant design and control strategy of hybrid modular DC transformer[J]. Transactions of China Electrotechnical Society, 2022, 37(2): 409-423. [5] Zogogianni C G, Tatakis E C, Porobic V.Investigation of a non-isolated reduced redundant power processing DC/DC converter for high-power high step-up appli- cations[J]. IEEE Transactions on Power Electronics, 2019, 34(6): 5229-5242. [6] Zhao Tao, Zhang Xing, Wang Mingda, et al.Module power balance control and redundancy design analysis of cascaded PV solid-state transformer under fault conditions[J]. IEEE Journal of Emerging and Selected Topics in Power Electronics, 2021, 9(1): 677-688. [7] Kang J, Kim H, Jung H J, et al.On exploiting active redundancy of a modular multilevel converter to balance reliability and operational flexibility[J]. IEEE Transactions on Power Electronics, 2019, 34(3): 2234-2243. [8] Tu Pengfei, Yang Shunfeng, Wang Peng.Reliability- and cost-based redundancy design for modular multilevel converter[J]. IEEE Transactions on Industrial Electronics, 2019, 66(3): 2333-2342. [9] Xie Xiangjie, Li Hui, McDonald A, et al. Reliability modeling and analysis of hybrid MMCs under different redundancy schemes[J]. IEEE Transactions on Power Delivery, 2021, 36(3): 1390-1400. [10] Zhang Wenping, Xu Dehong, Enjeti P N, et al.Survey on fault-tolerant techniques for power electronic converters[J]. IEEE Transactions on Power Electro- nics, 2014, 29(12): 6319-6331. [11] Li Cheng, Wang Haoyu, Shang Ming.A five-switch bridge based reconfigurable LLC converter for deeply depleted PEV charging applications[J]. IEEE Transa- ctions on Power Electronics, 2019, 34(5): 4031-4035. [12] Costa L F, Buticchi G, Liserre M.A family of series- resonant DC-DC converter with fault-tolerance capability[J]. IEEE Transactions on Industry Appli- cations, 2018, 54(1): 335-344. [13] Li Yang, Zhang Yan, Cao Rui, et al.Redundancy design of modular DC solid-state transformer based on reliability and efficiency evaluation[J]. CPSS Transactions on Power Electronics and Applications, 2021, 6(2): 115-126. [14] 王议锋, 陈晨, 陈博, 等. 一种基于串联输入并联输出型LLC的噪声抑制磁集成方法[J]. 电工技术学报, 2022, 37(9): 2319-2328. Wang Yifeng, Chen Chen, Chen Bo, et al.A magnetic integrated method for noise suppression based on input-series output-parallel LLC[J]. Transactions of China Electrotechnical Society, 2022, 37(9): 2319-2328. [15] Roy S, Joisher M, Hanson A J.A decentralized nonlinear control scheme for modular power sharing in DC-DC converters[C]//2021 IEEE Energy Con- version Congress and Exposition (ECCE), Vancouver, Canada, 2021: 2798-2805. [16] 谢沁园, 王瑞田, 林克文, 等. 基于端口电压积分与变下垂系数的逆变器并联下垂控制策略[J]. 电工技术学报, 2023, 38(6): 1596-1607. Xie Qinyuan, Wang Ruitian, Lin Kewen, et al.Droop control strategy of parallel inverters based on port voltage integration and variable droop coefficient[J]. Transactions of China Electrotechnical Society, 2023, 38(6): 1596-1607. [17] 沈冲, 吴红飞, 高尚, 等. 基于光伏-储能集成功率模块的航天器分布式供电系统能量管理策略[J]. 中国电机工程学报, 2020, 40(20): 6674-6681. Shen Chong, Wu Hongfei, Gao Shang, et al.Power management strategy of a PV-battery-integrated power module-based distributed power system for spacecrafts[J]. Proceedings of the CSEE, 2020, 40(20): 6674-6681. [18] Munir M S.Residential distribution system harmonic compensation using priority driven droop con- troller[J]. CPSS Transactions on Power Electronics and Applications, 2020, 5(3): 213-223. [19] Chen Jie, Yan Shuo, Yang Tianbo, et al.Practical evaluation of droop and consensus control of distributed electric springs for both voltage and frequency regulation in microgrid[J]. IEEE Transa- ctions on Power Electronics, 2019, 34(7): 6947-6959. [20] 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 transformer LLC and output interleaved Buck[J]. Transactions of China Electrotechnical Society, 2015, 30(24): 93-102.