基于重心重合原则的数字化多电平SPWM方法

Digitalized Multilevel SPWM Method Based on Cg-superposition Theorem

针对多载波正弦脉宽调制(SPWM)方法的不足,提出了一种数字化重心重合SPWM(CSSPWM)方法。先将参考正弦信号的第一个1/4周期分为若干等份,在每一个等份中用面积相等、重心重合的凸形波代替原参考信号。该方法不受拓扑结构和多电平逆变器输出电平数的约束,适用于所有的多电平逆变器。以五电平逆变器为例,对多电平逆变器的CSSPWM方法进行了仿真和实验研究,结果证明了该方法具有较小的总谐波畸变和较高的基波控制精度。

To overcome the shortcomings of the multi-carrier based sine pulse width modulation（SPWM） method,a novel digital cg-superposition SPWM（CSSPWM） scheme is proposed.The first quarter cycle of reference sine signal into several sections is divided equally.The reference signal in each section is substituted by protruding signals with same area.Their centers of gravity are superposed.The CSSPWM method is not restricted to the topology and numbers of output levels of the multilevel inverters and fit for all kinds of multilevel inverters.Taking a five-level inverter as an example,the CSSPWM method is investigated by simulation and experiment.The results prove that the CSSPWM method has lower total harmonic deformation and higher precision of fundamental control.