电网电压三相不平衡时CVUF相角因素对异步电机运行性能影响

Influences of CVUF's phase-angle factor on operation performance of asynchronous motor under unbalanced three-phase grid voltage

电网电压不平衡会对异步电动机的运行造成不良影响,因此研究三相电网电压不平衡时复数电压不平衡度(CVUF)的相角因素对异步电动机运行性能的影响。首先分析了三相绕组电压幅值、相位和CVUF间的关系,基于此,以1台5.5 kW Y132S-4异步电动机为例,在正序电压380 V、CVUF幅值恒定以及75%负载条件下,分析了CVUF相角因素对异步电机的定子电流、损耗、转矩性能的影响。结果表明:异步电机定子三相电流均随CVUF相角呈正弦规律变化,为避免带载能力下降过多及绕组过热,异步电机应避免运行在定子电流最大值处;CVUF相角对各项损耗、起动性能及稳态转矩脉动分量影响较小。最后计算了不同电压平衡条件下的异步电机三相定子电流和内部各项损耗,结果与实测结果基本一致,证明了理论分析的正确性。

Since the unbalanced grid voltage impacts on the proper operation of asynchronous motor , the influence of the phase-angle factor of CVUF（Complex Voltage Unbalance Factor） on the operational performance of asynchronous motor during three-phase grid voltage unbalance is studied. The relationship between CVUF and the amplitude/phase of three-phase winding voltage is analyzed,based on which,the influence of CUVF＇s phase-angle factor on the stator current,loss and torque performance of a 5.5 kW Y132S-4 asynchronous motor is studied when the positive-sequence grid voltage is 380 V,the CVUF＇s amplitude is constant and the load rate is 75%. Results show that,the three-phase stator current follows the sinusoidal variation of CVUF＇s phase-angle;the asynchronous motor should not operate at the point of maximum state current to avoid the deep drop of load ability and the overheating of windings;CVUF＇s phase-angle has slight influence on tbe losses,startup performance and torque ripple components. The three-phase stator currents and losses of asynchronousmotor are calculated for different voltage balance conditions and the calculative results are basically the same as the measured results,showing the correctness of the theoretical analysis.