串联H桥多电平变频器中的功率平衡方法

A New Power Balancing Method for Cascaded H-Bridge Multilevel Inverter

在串联H桥多电平调速系统中 ,为使一相中各串联H桥单元输出功率平衡 ,需要对其相应的脉冲循环控制进行研究。传统的等控制周期循环法虽能达到此目的 ,但功率器件开关动作次数多 ,损耗大。本文提出的错位等周期循环法 ,在大多数输出电压范围内 ,功率器件开关动作次数减少一半 ,可大幅度降低开关损耗 ,提高系统效率。

Proper pulse rotation pattern must be studied in cascaded H bridge multilevel inverter drive system to balance the output power of all H bridge cells.The conventional equal period rotation pattern can be used,but all the devices must be switched on and off frequently and the switch loss is increased.A new stagger equal period(SEP) rotation pattern is put forward in this paper and the switching times can be reduced by half under most output voltage.Consequently,switch loss can be decreased greatly and the efficiency of the whole system can be increased.