改进型PWM调制多电平逆变器研究

Research for Multilevel Inverter with an Improved PWM Method

针对带独立直流源的级联型多电平逆变器各逆变单元间应力分配不均衡提出了一种新的调制方法。通过控制各逆变单元开关的导通顺序和导通时间改善各逆变单元间应力分配不均衡 ,使整个逆变器工作更稳定。对于 N电平的级联型逆变器 ,提出了分组循环思想 ,解决传统的循环控制策略过于复杂而难于实现的问题。

A novel modulation method for cascaded multicell inverter with separated dc sources is presented in this paper to balance the unequal power distribution among different invert cells.Controlling the sequence and working time of the switching status of every invert cell is an easy way to avoid unbalanced power distribution among invert cells,so that the whole system can work more stably in general.For N level inverter,an controlling idea of grouping and cycling among every inverting cell is also developed.Simulation results are presented to verify the effectiveness of the proposed control strategy.