三相系统关联指令脉宽调制(PWM)技术

Three Phase System Pulse Wide Modulation(PWM) Technique Based on Incidence References

在三相逆变器系统中，逆变器三个桥臂的输出电压通常是以相电压指令进行独立调制．本文提出的三相系统关联指令脉宽调制（ＰＷＭ）技术是指把一个周期分成几个区，在不同的分区内，其中一个桥臂不调制，其它两个桥臂以相电压的关联线电压指令进行调制．关联指令ＰＷＭ技术的着眼点是对线电压进行直接控制．理论分析表明，这种调制方法输出线电压的载波频率可达开关工作频率的１．５倍，逆变器的输出电压比传统调制方式的输出电压提高１５．４７％．

Generally, in a three phase inverter system, every output voltage of three arms is modulated independently referring to voltage reference of every phase. However, the three phase system PWM technique based on incidence references proposed in this paper is quite different from the others PWM. It divides one cycle into several areas. In a specialzied area ,output voltage of one arm is not modulated while output voltage of the other two are modulated referring to incidence reference of every two phase voltage, that is the incidence instruction of line voltage. The key point of this technique is the direct control of line voltage. Theoretical analysis shows that the carrying frequency of the output line voltage using this method is 1.5 times as the switching frequency, and the output voltage of the inverter using this technique is improved by 15 47% compared with that using ordinary method.