Thrust Ripple Reduction Method of Electromagnetic Suspension Actuator Considering Cogging Forces and Ripple Forces

Abstract

Abstract: A novel permanent magnet linear electromagnetic suspension actuator was designed based on in-wheel motor electric vehicle.Aiming at reducing thrust ripple of the actuator， a method was proposed based on optimizing cogging forces under no-load conditions and ripple forces under load condition.Theoretical model of the actuator was established， and the finite element model （FEM） was verified through comparisons of simulation results and analytical ones， including the winding flux-linkages and induced electromotive forces（EMF）.Based on the FEM， the influences of the actuator end tooth lengths on cogging forces were conducted under no-load conditions by using parameter analysis method.The actuator stator lengths were optimized.In addition， total harmonic distortion （THD） was taken as evaluation index to induced EMF，ripple force was considered under load conditions， THD and thrust ripple were reduced by optimizing slot widths.The results show that the minimum cogging force is as 24.0N， which is obtained at the stator length 182 mm， and cogging force is reduced by 75.6N.Minimum THD of induced EMF is 4.5%， which is obtained at the slot width 4.5 mm.Ripple force is reduced 3.2N， electromagnetic force ripple of improved actuator is only 20.8N and is reduced by 80.1%.Thus， the disadvantages of the serious thrust ripples are solved effectively.

Key words: electric vehicle, wheel-drive, electromagnetic suspension actuator, electromagnetic force ripple

摘要： 针对轮边驱动电动汽车设计了一种直驱式的电磁悬架作动器。针对作动器存在的电磁力波动大的问题，提出了从空载定位力及负载波纹力两方面进行抑制的方法。建立作动器的磁场理论计算模型，通过对绕组磁链及感应电动势进行解析，验证了有限元模型的正确性。空载情况下基于有限元模型参数化分析了端部齿长度对定位力的影响，改进了定子长度。以感应电动势总谐波畸变率THD值作为评价指标，考虑了负载情况下的波纹力，通过改进槽口的宽度，以减小THD值及电磁力的波动。结果表明：当定子长度为182 mm时，定位力最小为24.0N，减小了75.6N；当槽口宽度为4.5 mm时，感应电动势THD值最小为4.5%，波纹力减小了3.2N。改进后作动器电磁力波动值仅为20.8N，降幅为80.1%，有效解决了波动力大的问题。

关键词: 电动汽车, 轮边驱动, 电磁作动器, 电磁力波动

CLC Number:

YANG Chao1;LI Yinong1，2;HU Yiming1;ZHONG Yinhui1. Thrust Ripple Reduction Method of Electromagnetic Suspension Actuator Considering Cogging Forces and Ripple Forces[J]. China Mechanical Engineering.

杨超1;李以农1，2;胡一明1;钟银辉1. 考虑定位力及波纹力的电磁悬架作动器波动力抑制方法[J]. 中国机械工程.

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