用脉冲宽度按正弦规律变化而和正弦波等效的PWM波形即SPWM波形控制逆变电路中开关器件的通断，使其输出的脉冲电压的面积与所希望输出的正弦波在相应区间内的面积相等，通过改变调制波的频率和幅值则可调节逆变电路输出电压的频率和幅值-With pulse width according to the sine law of change and equivalent sine wave inverter PWM waveform of SPWM waveform control circuit switch on-off device, the output of the area of the pulse voltage and the hope of the output sine wave in the area of the corresponding interval equal, by changing the frequency and amplitude modulation wave is adjustable frequency and amplitude of the output voltage inverter circuit