SPWM是最常用的一种调制方法，SPWM信号是当改变正弦参考信号的幅值时，脉宽随之改变，从而改变了主回路输出电压的大小。当改变正弦参考信号的频率时，输出电压的频率即随之改变。-SPWM is one of the most commonly used modulation method, the SPWM signal is when the amplitude of the sinusoidal reference signal changes, the pulse width changes