基于中性点钳位型三电平中压变频器共模电压研究

Research on the Common-mode Voltage of the Neutral Point Clamped Three-Level Medium Voltage Drives

基于中性点钳位型三电平中压变频器的拓扑结构,本文分析了共模电压产生的机理,并推导出等效共模电压回路。与目前常用的基于共模电抗器的共模电压抑制方法,本文提出了通过输出滤波中性点接地的方式抑制电动机输入共模电压的方法,并且高压试验结果验证了该方法的有效性。

Based on the topology of the neutral point clamped （NPC） three-level medium voltage drives （MVDs）, the arising of the common-mode voltage （CMV） is discussed, and its corresponding equivalent CMV circuit is deduced in this paper. Compared with the CMV inductor used to suppress the CMV input to the motor, the method of grounding star point of the output filter is developed. Furthermore, the high voltage test show its efficiency.