基于P-Q变换的鼠笼式异步电动机转子故障仿真分析

Faults Simulation for Squirrel Cage Asynchronous Motor Rotor Based on P-Q Transformation

为对电动机进行可靠的实时监测与诊断,提出了基于P-Q变换的鼠笼式异步电动机转子的故障分析方法。该方法是通过同时采集三相电压和电流信号,由电压信号和电流信号相乘得到瞬时有功功率P,将三相电压经过Hilbert变换再与电流信号相乘得到瞬时无功功率Q,以P为横坐标,Q为纵坐标,得到P-Q图。由于正常情况下电动机P、Q均恒定,在P-Q坐标系下对应一个点,而断条故障时电动机频率中将会有附加成分,因而在P-Q坐标系下对应于一个椭圆,通过椭圆长轴的长度分析断条故障的严重性。仿真试验证明,这种方法在轻载情况下仍然有效。

In order to real time monitor and diagnosis the motors, proposes the rotor faults simulation for squirrel cage asynchronous motors based on P-Q transformation. This method collects three-phase voltage and current signal at the same time. The active power P is gained by the voltage signal multiplies the current signal. Then the three- phase voltage changes through Hilbert and multiplies current signal, gains the instantaneous reactive power Q. Takes the P as the abscissa and Q as the ordinate, the P-Q diagram is get. Due to the normal situation, the motor P, Q are constant. There is one point corresponds to a coordinate system. Because the motor frequency will have additional ingredient when the broken bar faults, so there is an ellipse corresponds in P-Q coordinate. Through the length of ellipse axis to analysis the serious of broken bar damage. The simulation test shows that this method still works under light load.