【摘要】 在本软开关三相PWM逆变器中 ,采用正负斜率锯齿载波调制方式 ,可实现逆变器开关器件的软开关动作 ,但同时会出现逆变器输出电流波形失真。本文根据电机相电流过零时的PWM动作模式和磁链轨迹 ,对此电流波形失真形成的原因进行了详细的分析 ,探明了其失真原因 ,提出了一种电流补偿方法 ,即在某相电流极性翻转后 ,立即对此载波周期中的PWM脉冲宽度进行调整 ,较好地改善了逆变器的输出电流波形。实验结果证明 :采用了本文提出的电流波形补偿方法后 ,逆变器输出电流波形具有良好的正弦度 ,系统谐波分量小。更多还原

【Abstract】 In a soft switching three phase PWM inverter using alternate (positive & negative slope) sawtooth carrier, although soft switching of the inverter can be realized, the output current waveforms for the inverter will be distorted. Based on flux linkage locus and PWM driven signal at zero crossing of motor phase current, the reason of such distortion is analyzed, and a current compensation method was brought forward, namely, the PWM pulse width in a carrier period should be adjusted immediately after one phase current polarity changes, which can greatly improve output waveforms for the inverter. Experiment results proved that by using such current compensation method the output current waveforms for inverter are sinusoidal and have low harmonic components.更多还原