一种差分对称型五电平逆变器拓扑及分析

大多数多电平逆变器通过前级结构产生不同水平的电压，后级连接到H桥臂以改变输出电压的方向。由于H桥谐波成分高，并且增加了成本，故提出一种差分对称型五电平逆变器。该逆变器拓扑结构对称、控制简单、谐波低，不需要额外的桥臂来改变输出电压的方向，其本身既能产生多个电平又能改变输出电压方向。此外，该逆变器在一个运行周期中，电容均只有一个模态放电，因此电容充电时间大于放电时间，故有足够的能量供给负载。利用MATLAB/Simulink对所提逆变器进行了仿真分析，并搭建了样机进行试验验证，仿真和试验结果与理论分析一致，证明了所提逆变器的有效性。

Topology and Analysis of a Differential Symmetrical Five Level Inverter

Most multi-level inverters generate different levels of voltage through the front stage structure, and the rear stage is connected to the H-bridge arm to change the polarity of the output voltage. Due to the high harmonic content and increased cost of H-bridge, a differential symmetric five-level inverter is proposed. The inverter topology structure is symmetrical, easy to control, and has low harmonics. It does not require additional bridge arms to change the polarity of the output voltage, and the topology itself can generate multiple levels while also changing the polarity of the output voltage. In addition, the inverter has only one mode of discharge for each capacitor in one operating cycle, so the charging time of the capacitor is greater than the discharge time, and there is sufficient energy to supply the load. The proposed inverter was simulated using MATLAB/Simulink and a prototype was built for experimental verification. The simulation and experimental results were consistent with theoretical analysis, proving the effectiveness of the proposed inverter.