长电缆连接的PWM驱动系统电机端过电压模型

Overvoltage Model of Motor End of PWM Drive System Connected by Long Cables

变频器的大量使用,对电机绝缘产生较大影响,尤其是通过长电缆连接的PWM驱动系统在电机端会产生一个明显高于变频器输出的过电压,严重危害电机绝缘。本文基于等效开路电压和短路电流,构建了电机端过电压的数学模型,并通过仿真结果与理论分析比较验证了此方法分可行性。最后,通过构建的模型,分析了此系统中一些因素对电机端电压的影响。

The wide use of frequency inverter had a great influence on motor insulation,especially for the PWM drive systems connected by long cables generate an overvoltage that was significantly higher than the output of the inverter at the motor end.This overvoltage would seriously damage the insulation of the motor.By calculating the equivalent open circuit voltage and short circuit current,the mathematical model of such PWM drive systems’overvoltage at the motor end was established in this paper.Then,the feasibility of the proposed method was verified through the simulation results.Finally,through the constructed model,the influence of some influencing factors on the motor terminal voltage in this system was analyzed.