逆变器驱动电机系统中共模耦合电流的研究

在电机驱动系统中，共模电压将会在电机内部的共模耦合回路中产生共模耦合电流，共模耦合电流将对系统构成共模干扰，并影响电机的使用寿命，因此对共模耦合电流的研究显得非常重要．文中分析了三相逆变器驱动电机系统中的共模激励源，发现共模响应只与系统的零序阻抗和共模阻抗有关，可以用等效的集总参数模型来模拟系统的共模耦合．在对电机内部的共模回路进行分析计算的基础上，得出了地电流及电机轴承电流的集总参数电路模型和参数确定方法，仿真和实验结果显示，该模型能对逆变器驱动电机系统中的地电流和轴承电流进行有效的预测。

Analysis of Common Mode Coupling Currents in Inverter PWM Drive Systems

In inverter PWM drive system, common mode voltage may produce common mode current in the common mode circuit of motor. The common mode coupling current may form common mode disturbance to the drive system and influence the life span of motor . So it is importance to analyzing the common mode coupling current in motor drive systems. This paper analyzes the source of common mode excitation and finds out that the common mode responses are only associate with the zero sequence impedance and common mode impedance. An equivalent lumped parameter circuit can used to model the common mode coupling of the systems. Based on the analysis of the common mode circuit in a induction motor, a lumped parameter circuit model is derived for analyzing the ground leakage current and bearing current from an ae induction motor driven by a voltage source pulse width modulation inverter. Parameter identification method of the model is given. The validity and effectiveness of the model are confirmed by simulation and experiment.