电工技术学报2025，Vol.40Issue(22)：7107-7126,20.DOI:10.19595/j.cnki.1000-6753.tces.241905
切向励磁型磁场调制电机的附加磁动势及其抑制技术综述
Overview of Additional Magnetic Motive Force in Spoke-Array Flux Modulation Permanent Magnet Machines and Its Suppression Technologies
摘要
Abstract
Due to their small equivalent airgap length and high flux-focusing capability,spoke-array flux modulation permanent magnet(SA-FMPM)machines offer the advantage of high torque density,thus having great potential in low-speed,direct-drive applications.However,the"flux barrier effect"that exists in SA-FMPM machines becomes an obstacle to enhancing the flux modulation effect and torque capacity.The key is to suppress the additional magnetic-motive-force(MMF).This paper explores the additional MMF in SA-FMPM machines,with a focus on its suppression technologies. Firstly,this paper introduces the generation mechanism of the additional MMF from the magnetic potential drop and the magnetic circuit aspects—the additional MMF results from the fluctuating unequal magnetic potential of each rotor's ferromagnetic poles over time.The defining formulas and mathematical models are developed to quantify the magnetic potential fluctuation,and the detrimental effects of additional MMF on motor performance are analyzed.Secondly,this paper presents three types of effective additional MMF suppression strategies:weakening or eliminating magnetic potential fluctuations,designing flux barriers or flux bridges,and optimizing magnet arrangement.The interrelations and distinctions of these strategies are also analyzed.The existing spoke-array permanent magnet machine topologies and the structural innovations in suppressing additional MMF are overviewed.Their advantages and disadvantages are summarized and evaluated as follows.(1)The principle underlying the weakening/elimination of magnetic potential fluctuations lies in forcing the homopolar rotor ferromagnetic poles to have equal magnetic potential by adding an iron yoke.The other approach is to compensate for the variation in lumped magnetic conductance during rotor rotation.Specifically,the single-bridge,double-bridge,and double-stator topologies are derived.These topologies can significantly weaken the additional MMF,and some can eliminate the magnetic potential fluctuation.However,the machine's overload capacity is poor due to its easy saturation.(2)The flux barrier/flux bridge design can lead to variations in magnetic reluctance.The core ideal is to achieve the dual change of both"magnetomotive-force unit"and"permeance unit".The relevant designs include H-,C-,U-,and V-shaped asymmetric flux barrier/bridge structures.These topologies can improve the flux modulation effect,but are limited in suppressing additional MMF.(3)The ideal of magnet arrangement optimization utilizes the"electromagnetic superimposition"theory to improve the flux-focusing ability.Alternatively,the reluctance torque is introduced to compensate for the torque component weakened by additional MMF.The derived topologies are classified into reinforced flux-focusing magnet and spoke-array interior magnet designs.These topologies can reduce flux leakage and enhance primitive PM-excited MMF or synthetic torque,but generate non-working harmonics,thereby increasing losses. This paper discusses the connections between additional MMF and the existing high-performance machine design techniques from rotor-side,stator-side,and harmonic synergetic optimization design perspectives.Moreover,various machine design techniques are further elaborated.The existence of additional MMF is extended to other magnet-inserted machines.Finally,this paper suggests future research directions for additional MMF phenomena.关键词
附加磁动势/切向励磁型磁场调制电机/磁位波动/转矩性能Key words
Additional magnetic motive force/spoke-array flux modulation permanent magnet(SA-FMPM)machines/magnetic potential fluctuation/torque performance分类
信息技术与安全科学引用本文复制引用
方颖,梁子漪,李大伟,曲荣海..切向励磁型磁场调制电机的附加磁动势及其抑制技术综述[J].电工技术学报,2025,40(22):7107-7126,20.基金项目
国家重点研发计划项目(52337001)、国家自然科学基金重大项目(51991382,51991381)、中国博士后科学基金面上项目(2023M741250)和博士后创新人才支持计划项目(BX20220120)资助. （52337001）
