五相U型永磁凸极直线电机对比分析

Comparative analysis of five-phase U-shaped permanent magnet salient pole linear motor

针对直线电机垂直提升系统(LMVHS)无绳化直驱运行,对高容错性、大推力密度的新型直线电机的迫切需求,提出一种五相U型永磁凸极直线电机(FU-PMSPLM),初级设置五相绕组以提高电机容错运行能力,次级永磁体采用U型结构以提高永磁利用率。首先,从降低漏磁角度,分析了U型磁极结构演化机理,并给出电机主要结构参数;其次,采用有限元法对比分析了电机次级永磁体采用U型与Halbach结构的电磁特性,并基于磁动势不变原则,以A相缺相故障为例,与三相U型永磁凸极直线电机(TU-PMSPLM)对比分析了容错性能;最后,制作实验样机并进行实验验证,样机实测与仿真结果基本一致。研究表明,等永磁体用量时,次级采用U型结构较Halbach结构,气隙磁通密度幅值增大13.89%,平均推力提高7.54%,推力波动降低25.07%;FU-PMSPLM较TU-PMSPLM具有更好的缺相运行能力。

Aiming at the cordless direct drive operation of linear motor vertical lifting system(LMVHS),there is an urgent need for a new type of linear motor with high fault tolerance and high thrust density,a five-phase U-shaped permanent magnet salient pole linear motor(FU-PMSPLM)is proposed.The primary set five-phase winding to improve the fault-tolerant performance,and the secondary permanent magnets(PMs)with U-shaped structure can make full use of the PMs.Firstly,from the perspective of reducing magnetic flux leakage,the evolution mechanism of U-shaped magnetic pole structure is analyzed,and the main structural parameters of the motor are given.Secondly,the finite element method(FEM)is used to compare and analyze the electromagnetic characteristics of the U-shaped and Halbach structure of the motor secondary permanent magnet.Based on the principle of constant magnetomotive force,by taking the phase A fault as an example,the fault tolerance performance of the three-phase U-shaped permanent magnet salient pole linear motor(TU-PMSPLM).Finally,the experimental prototype is made and the experimental verification is carried out,the experimental results are basically consistent with the simulation results,which verifies the rationality and feasibility of the proposed motor.The results show that when the amount of permanent magnet is equal,the U-shaped structure of the secondary permanent magnet is compared with the Halbach structure,the amplitude of the air gap flux density increases by 13.89%,the average thrust increases by 7.54%and the thrust fluctuation decreases by 25.07%.FU-PMSPLM has better phase-deficient operation ability than TU-PMSPLM.