一种基于开关电容的单电源升压型六电平逆变器

针对现有开关电容型多电平逆变器存在拓扑结构复杂、器件数量较多、电容电压不平衡以及电压应力较大等缺点，提出一种新型的基于开关电容的六电平逆变器。该电路拓扑由6个功率开关、1个直流电压源和3个电容组成，可以产生2.5倍升压增益的六电平输出电压。此外，由于电容由输入直流电压源直接充电至固定电压，因此电容电压能够实现自动平衡。对所提逆变器的工作原理、PWM调制策略以及电路参数等方面进行详细分析，同时还对该逆变器与现有多电平逆变器进行了对比研究。最后采用Matlab软件建立了仿真模型，仿真结果验证了所提电路的有效性和可行性。

A single supply boost six-level inverter based on a switched-capacitor

There are problems associated with complex topologies, large numbers of devices, unbalanced capacitor voltages and high total standing voltage stresses in existing switched-capacitor based multilevel inverters. Thus a new six-level inverter based on a switched-capacitor is proposed. The proposed structure consists of six switches with a single DC voltage source and three floating capacitors. It is capable of producing a six-level output voltage waveform with a voltage boosting gain of 2.5 times. The voltages of the capacitors are constructively balanced because they are directly charged to fixed voltage by the input DC voltage source. The operating principle, PWM modulation strategy and circuit parameters of the proposed inverter are analyzed in detail. A comparative study between the proposed inverter and other existing multilevel inverter topologies is also discussed. Finally, a simulation model is established in Matlab software, and the results verify the effectiveness and feasibility of the proposed circuit.This work is supported by the National Natural Science Foundation of China (No. 61702182).