改进式SHEPWM对三电平变频器系统的共模电压和轴电压的抑制作用

降低三电平中点钳位式变频器驱动电机的共模电压和轴电压,减小轴电流,对预防定子绕组绝缘击穿和延长轴承寿命以及减小电磁干扰等具有重要意义。使用改进型特定谐波消除脉宽调制技术,选择消除变频器输出共模电压中的低频分量,再使用共模滤波器滤除剩余的高频分量,在电机端得到了较低的共模电压和轴电压。并对有、无共模滤波器以及在工频电网供电下的共模实验数据进行了对比分析,结果证实该方法简单高效。

Common Mode Voltage and Shaft Voltage Suppression on a Three-Level NPC Inverter System Applying Improved SHEPWM

The common-mode voltage (CMV) & shaft voltage of induction motor driven by inverter can cause great damage to motor stator insulation,bearing and cause EMI problem. An improved selective harmonics elimination pulse width modulation (SHEPWM) is applied in this paper to eliminate the low order components of the inverter CM voltage. And the high components of the CM voltage are attenuated by a well-designed CM filter. A satisfactory result of CM voltage & shaft voltage is obtained. A comparison of experimental...