中文摘要：

在PWM变频驱动系统中,逆变器产生的共模电压在电机耦合电容作用下,在轴承上产生轴电压和轴电流,影响电机轴承的寿命。研究轴电流的抑制方法,对PWM变频驱动系统的安全运行具有重要意义。首先分析了变频供电下交流电机轴电压形成机理,指出电机定转子间耦合电容Cwr对轴电流有重要影响,并针对定子完全屏蔽、部分屏蔽以及槽表面屏蔽这三种屏蔽措施的电机耦合电容进行了电磁场数值计算,分析了静电屏蔽导体的涡流损耗。对三种方法抑制轴电压和轴电流的效果进行了仿真分析。仿真结果表明,部分屏蔽方法的抑制效果与完全屏蔽的抑制效果相当,且其涡流损耗要小于完全屏蔽法,是一种较好的抑制方法。

英文摘要：

The common mode voltage of PWM inverter drive system induces bearing voltage and bearing current in the motor under the influence of coupling capacitances of motors. Mitigation the bearing current is important to the safety operation of driving system. Firstly the reason of the bearing voltage and the bearing current of PWM driving system were analyzed. It is shown that the coupling capacitance Cwrbetween the stator winding and rotor is a key parameter to suppress the bearing current. Three electrostatic shield methods were analyzed,including stator complete electrostatic shielding,stator partial electrostatic shielding（ PES） and slot electrostatic shielding. The coupling capacitances under different electrostatic shield methodsare calculated with finite element method. The eddy current losses under different electrostatic shield methods were calculated. The mitigation effects of the three methods on bearing currents were analyzed through MATLAB simulation. The results show that PES is close to the stator complete electrostatic shielding,and eddy current loss of PES is less than stator complete electrostatic shielding,which is a better choice to mitigate bearing currents.