The spoke-type permanent magnet motor with auxiliary stator exhibits high torque performance owing to the flux focus effects.To further improve its torque density,this paper proposes a control method by using harmonic...The spoke-type permanent magnet motor with auxiliary stator exhibits high torque performance owing to the flux focus effects.To further improve its torque density,this paper proposes a control method by using harmonic current strategy.Based on the theoretical analysis,a 3-D torque look-up table by dq-axis current and electrical angle is established with the aid of the finite element method(FEM).The maximum torque per ampere curve at each rotor position is identified and summarized to adequately indicate the relationship between torque and current amplitude of the motor.Through theoretical derivation,it is concluded that the minimum torque cost curve is the contour line of?Te/?i2,which can be employed to identify the harmonic current for torque density improvement.Compared to traditional strategies,the proposed control strategy can increase torque density of forward and reverse torque by 1.22%and 1.40%,respectively.The experimental results verify the analysis and simulation results,as well as prove the effectiveness of the proposed strategy.展开更多
Due to magnetic gearing effects,spoke-type permanent magnet vernier machines(ST-PMVMs)have the merit of high torque density,where an extra torque amplification coefficient,i.e.,pole ratio(the pole-pair ratio of PMs to...Due to magnetic gearing effects,spoke-type permanent magnet vernier machines(ST-PMVMs)have the merit of high torque density,where an extra torque amplification coefficient,i.e.,pole ratio(the pole-pair ratio of PMs to armature windings)is introduced.However,different from surface-mounted PMVM,the variation of torque against pole ratio in ST-PMVMs is non-linear,which is increased at first and then decreased.This article is devoted to identify the optimal pole ratio of ST-PMVMs by equivalent magnetic circuit model.It is found that except the Prth air-gap magnetomotive force(MMF)harmonic having the same pole-pair of PM,the Path air-gap MMF harmonic having the same pole-pair of armature winding is also induced due to the modulation of doubly salient air-gap structure.The Prth MMF harmonic produces positive torque,while Path MMF harmonic produces negative torque.With the increase of pole ratio,the proportion of Path MMF harmonic as well as negative torque is increased,which reduces the advantages of high pole ratio coefficient.Further,the influence of dimension parameters on the performance of ST-PMVMs under different pole ratio are investigated.Results show that ST-PMVMs with pole ratio 2.6 have high torque density,low cogging torque and high power factor simultaneously.Finally,a prototype is manufactured to validate the analysis.展开更多
基金supported in part by the National Natural Science Foundation of China under Grant 52077123 and 51737008in part by the Natural Science Foundation of Shandong Province of China for Outstanding Young Scholars,under Grant ZR2021YQ35。
文摘The spoke-type permanent magnet motor with auxiliary stator exhibits high torque performance owing to the flux focus effects.To further improve its torque density,this paper proposes a control method by using harmonic current strategy.Based on the theoretical analysis,a 3-D torque look-up table by dq-axis current and electrical angle is established with the aid of the finite element method(FEM).The maximum torque per ampere curve at each rotor position is identified and summarized to adequately indicate the relationship between torque and current amplitude of the motor.Through theoretical derivation,it is concluded that the minimum torque cost curve is the contour line of?Te/?i2,which can be employed to identify the harmonic current for torque density improvement.Compared to traditional strategies,the proposed control strategy can increase torque density of forward and reverse torque by 1.22%and 1.40%,respectively.The experimental results verify the analysis and simulation results,as well as prove the effectiveness of the proposed strategy.
基金supported in part by the National Nature Science Foundation of China(NSFC)under Project 51977094in part by the National Key Research and Development Program of China under Grant 2017YFB0102400。
文摘Due to magnetic gearing effects,spoke-type permanent magnet vernier machines(ST-PMVMs)have the merit of high torque density,where an extra torque amplification coefficient,i.e.,pole ratio(the pole-pair ratio of PMs to armature windings)is introduced.However,different from surface-mounted PMVM,the variation of torque against pole ratio in ST-PMVMs is non-linear,which is increased at first and then decreased.This article is devoted to identify the optimal pole ratio of ST-PMVMs by equivalent magnetic circuit model.It is found that except the Prth air-gap magnetomotive force(MMF)harmonic having the same pole-pair of PM,the Path air-gap MMF harmonic having the same pole-pair of armature winding is also induced due to the modulation of doubly salient air-gap structure.The Prth MMF harmonic produces positive torque,while Path MMF harmonic produces negative torque.With the increase of pole ratio,the proportion of Path MMF harmonic as well as negative torque is increased,which reduces the advantages of high pole ratio coefficient.Further,the influence of dimension parameters on the performance of ST-PMVMs under different pole ratio are investigated.Results show that ST-PMVMs with pole ratio 2.6 have high torque density,low cogging torque and high power factor simultaneously.Finally,a prototype is manufactured to validate the analysis.
