Single-Source Self-Voltage-Balancing Nine-Level Inverter and Its Modulation Strategy
Wang Yaoqiang1, Zhou Chenglong1, Li Zhongwen1, Zhang Yun2
1. School of Electrical Engineering Zhengzhou University Zhengzhou 450001 China; 2. School of Electrical and Information Engineering Tianjin University Tianjin 300072 China
Abstract：In distributed renewable energy generation systems, traditional multi-level inverters have the disadvantages of too many power devices, complicated circuit structure and control strategy. To solve these problems, a single-source nine-level inverter based on switched capacitor structure is proposed, which consists of switched capacitor network, auxiliary bidirectional switch and H-bridge unit. The proposed inverter can generate more output levels with less power devices, moreover, the topology is simple and has the advantage of low output harmonic content. The advantages of capacitor self-voltage-balancing simplify the control algorithm, and the characteristics of single source can broaden its application range. The specific harmonic elimination method is used to modulate the inverter, which reduces the switching frequency of switches and further reduces the harmonic content of the output voltage. Finally, the steady and dynamic performance of the proposed inverter is verified and analyzed by experiments, which proves the correctness and feasibility of the inverter and its modulation strategy.
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2020, Vol. 35 
