一种高功率因数谐振异步电机特性分析

Characteristic analysis of a high power factor resonant asynchronous motor

传统交流异步电机仅在额定工况下可以维持较高的功率因数,而在其他各类工况下功率因数较低。针对这一问题,通过在绕线式异步电机转子/次级回路上串接电容来补偿异步电机的功率因数,提出了一种谐振异步电机。选择适当的电容容值及转差频率,可以有效提高异步电机的功率因数,最高可以将功率因数提高至1。分析了谐振异步电机等效电路,基于等效电路对其功率因数特性进行了推导和分析,并采用一组电机参数将功率因数特性及转矩/推力特性与常规异步电机进行了对比分析。分析结果表明:在相同的电机参数下,所提出的谐振异步电机相较常规异步电机,在全速域具有高功率因数的特点;在输出同样的转矩/推力的情况下,谐振异步电机需要的定子电流更小、母线电压更低,适用于电磁推进/弹射的应用场景,可减小系统规模及建设成本,也可应用于一般的绕线式异步电机进行无功补偿。

The traditional AC asynchronous motor can maintain a high power factor only under rated conditions,and the power factor is low under other conditions.In order to solve this problem,a kind of resonant asynchronous motor was proposed to compensate the power factor of the asynchronous motor by connecting capacitors in series on the rotor/secondary loop.The power factor of induction motor can be effectively improved(the highest increased to 1)by choosing the appropriate capacitance and slip frequency.The equivalent circuit of resonant asynchronous motor was analyzed,based on which the power factor characteristics were deduced and analyzed.The characteristics of power factor and torque/thrust were compared between conventional asynchronous motors and resonant asynchronous based on a set of motor parameters.Analysis results show that under the same motor parameters the proposed resonant asynchronous motor,compared with conventional asynchronous motor,is characterized by high power factor in all range of speed.For the output of the same torque/thrust,resonant asynchronous motor needs smaller stator current and lower bus voltage than regular asynchronous motor,and thus reduces the system size and cost of construction,which is suitable for the application of electromagnetic propulsion/ejection scenario.It can also be applied to the general wound induction motor for reactive power compensation.