一种新的多电平逆变器特定谐波消除脉宽调制方法

A Novel Selective Harmonics Elimination PWM Method for Multilevel Voltage Inverters

基于多电平逆变器特定谐波消除脉宽调制(SHEPWM)方法的波形对称方案,提出了一种新的多电平逆变器半周期对称波形SHEPWM方法,可以求取许多现有方法不能求得的数值解,具有通用性强、形式简单、波形灵活、易于编程、解的空间大等优点.以五电平逆变器为例,取半个周期内20个开关切换点,对调制比为0.8时的非线性方程组进行求解,求取了12组数值解,抽取其中2组进行仿真和实验研究,证明了所提SHEPWM方法的有效性和实用性.

The schemes of waveform symmetry of selective harmonic elimination （SHE;） PWM methods for multilevel voltage inverters were investigated. In order to provide more opportunities for optimization de-sign in practice, a novel generalized half-wave symmetry SHEPWM method was proposed. The advantages of the proposed method include simplicity in format, flexibility in PWM waveforms and a broad solution space. Taking a five-level inverter with 20 points in half a cycle as an example, twelve groups of solutions at modulation index （M） of 0.8 were obtained. Simulations based on two groups of selected keys were car-ried out. An experimental prototype with a five-level cascade voltage inverter topology was built and inves-tigated based on the same keys. The experimental results agree well with the simulated ones and prove the validity and practicability of the new method.