一种新型的级联型逆变器PWM信号随机分配方法研究

RANDOM PWM DISTRIBUTION OF CASCADED INVERTER

级联型逆变器具有开关冗余和隔离直流电源冗余。该文提出采用随机分配的方法来均衡开关和电源的利用率。当控制器给出输出电平后,电源和开关器件的工作状态是由两个随机函数决定的。随机函数具有均匀分布特性,可以由线性同余法来实现。当输出波形正负对称时,逆变器的每个单元处于工作状态的概率是相同的。随着逆变器工作时间的延长,各单元的利用率自然趋于相同。仿真和实验结果证明了该方法的可行性。

There are switch redundance and dc source redundance in cascaded inverter. This paper proposes a novel random PWM distribute method to balance usage of switch and dc source. After output voltage is given by control arithmetic, pattern of switch and dc source are determined by two random functions, which can be realized by line congruential method. When output voltage is symetic, the active probability of each unit is same. With the devices working longer, the usage rate of each unit is going to be the same. Result of simulation and experiments show the affective of this method.