非连续供电模式下感应电机低频振荡机理分析

采用对称分量法,排除变频器一侧电感和电容影响,对感应电机在最简单的不连续供电模式下(晶闸管供电)的振荡现象进行研究。通过分析电机在三相及两相导通模式下的换相瞬态过程,考虑转速改变时电机方程各量的变化,推导电机在不同过渡过程时其定转子电流的空间向量表达式,并给出其时域形式解,找到感应电机在不连续供电时产生振荡的原因,从电机本体方面对振荡现象进行解释。应用上述分析方法对一台三相感应电机进行计算,计算结果与实验吻合较好。分析方法可作为进一步研究变频器供电的感应电机的过渡过程的基础。

Low frequency oscillation mechanism research on induction motors under discontinuous power supply

In order to avoid influence from inductance and capacitance on the inverter side,symmetrical components theory was introduced to study the oscillation of induction motor supplied by thyristors.This is the simplest discontinuous supply mode,but can give suggestions for more complex situation.The transient process of phase exchange and speed variation were analyzed when the motor was powered by 2 and 3-phase voltage,and the space-vector expression of stator and rotor current during different transient process was analyzed,and its time domain solution was given.The cause of oscillation was found out when induction motor worked at discontinuous power supply,and explanation of oscillation was presented in the view of the motor itself.A 3-phase induction motor was analyzed using the theory given above.It proves that calculation results are very close to the measurement results,and this method can be the basis for transient process study of induction motor supplied by inverters.