变频器输出对调速电机影响的仿真

Simulation of the Effect of Transducer Output on Inverter Fed Motor

利用MATLAB提供的计算机仿真工具,对变频调速系统中的调速电机建立起合理的定子侧高频阻抗仿真电路,分析、计算在PWM等脉宽的方波电压脉冲波作用下调速电机定子绕组单相对地的电压分布情况,结果表明,变频调速电机输入端的过电压不仅仅由于连接电缆的传输、反射引起,PWM脉宽调制波中的大量高频谐波也能够引起更为严重的定子绕组匝间的过电压。可以利用RC无源滤波器进行高频成分的滤波,仿真结果说明滤波后高频谐波引起的过电压得到极大减小,定子绕组匝间电压分布均匀。

Using computer simulation offered by MATLAB, a model of inverted circuit of transducer and motor is set up. Frequency response of the motor input impedance under PWM pulsewidth modulation voltage pulse is ob- tained and analyzed. The results show that the over voltage problem not only exists in long cable caused by traveling -wave and reflection. Although the motor is not connected by a long cable. A lot of high frequency content that is present in a pulsewidth modulation voltage pulse can bring very high over voltage in the winding turn - to - turn of the motor input. In order to mitigate the over voltage caused by high frequency harmonic, this paper uses RC filter. And a simulation circuit model is set up. The simulation result shows that over voltage is decreased evidently by filtering and the voltage distribution is comparably even.