Abstract:The common mode voltage of PWM inverter drive system will induce bearing voltage and bearing current in the motor under the influence of the coupled capacitance of the motor. Accurate calculation of the coupled capacitance of the motor is important to forecast the bearing voltage. After analyzing the common mode circuit model of the system, the 2D and 3D finite element models of the motor are established respectively. The results show that the end part of winding is a key factor to the stator winding to rotor capacitance Cwr. The calculation considering the end part of winding in 3D analysis is more accurate than which in 2D analysis. It is concluded that the length of extended straight part of stator winding and the thickness of squirrel-cage ring in axial direction are two main factors which can affect Cwr. The 3D transient electric field finite element calculation is applied on an induction motor fed by inverter. The result shows that bearing voltage mirrors the common mode voltage, which verifies the effectiveness of the analysis model.
刘瑞芳,李俊峰,桑秉谦,曹君慈. 基于电磁场数值计算的变频供电感应电机耦合电容与轴电压的分析[J]. 电工技术学报, 2015, 30(14): 161-169.
Liu Ruifang,Li Junfeng,Sang Bingqian,Cao Junci. Modeling of Coupled Capacitances and Bearing Voltage in Induction Motors Fed by Inverters Based on Numerical Calculation of Electromagnetic Field. Transactions of China Electrotechnical Society, 2015, 30(14): 161-169.
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