长初级双边直线感应电机纵向动态端部效应 第二部分:性能计算

Longitudinal dynamic end effect in long primary double-sided linear induction motor Part 2: performance calculation

为了研究纵向动态端部效应对长初级直线感应电机磁场和性能的影响,在第一部分(文献[11])中,应用解析法对长初级双边直线感应电机的气隙磁场进行了分析;作为第二部分,在气隙磁密解析解的基础上,推导在纵向动态端部效应影响时该类电机性能的解析表达式,如电磁推力、有功及无功功率、功率因数和效率等.通过二维有限元数值计算验证了性能解析计算的正确性。基于气隙磁密相量图,研究了电机在高速运行时,入端行波推力成为制动力的原因以及对总推力特性的影响,分析了调整品质因数和极数等电机设计参数对推力的影响。研究结果表明,长初级结构在高速运行时推力特性变软、损耗增加、效率下降,调整品质因数对改善推力特性几乎没有影响,但增加极数可有效抑制纵向动态端部效应。

To investigate the influence of the longitudinal dynamic end effect （LDEE） on the magnetic field and performance of the long primary double-sided linear induction motor（LP-DSLIM）,the airgap magnetic field for LP-DSLIM was analyzed,in part 1,by using the analytical method.According to the derived analytical expressions of the airgap magnetic flux density,the analytical calculations,when taking into account LDEE,were extended to the prediction of the motor performances,which include electromagnetic thrust,active and reactive power,power factor and efficiency,etc in this part.The analytical results were compared and validated by the predictions from two-dimensioanl finite element analysis.The fact that thrust due to the entry-end effect comes into being as the braking force at high speed,and its influence on the resultant thrust-speed characteristics were investigated by the phasor diagram of the airgap magnetic flux density.The effects of the motor design parameters,including the goodness factor and the pole numbers,on the improving the high speed thrust-speed characteristics for LP-DSLIM were also analyzed.The analysis result show that LDEE makes the rated operating speed in the thrust-speed characteristics be far away from the synchronous speed,thereby resulting in the higher secondary copper losses and lower efficiency.Adjusting the goodness factor has little influence on the thrust improvement,while increasing the pole numbers could effectively alleviate LDEE.