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.
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2024, Vol. 39 
