Design And Analysis Of Flux Modulated Arc Permanent Magnet Machine

Arc permanent magnet machine(APMM)has the dual characteristics of rotary permanent magnet(PM)machine and linear PM machine.It has the advantages of simple structure,fast dynamic response and high torque density.In this dissertation,APMM is taken as the research object,and its topology structure design,multi-objective optimization,electromagnetic characteristics analysis and experimental test are studied,which provides the theoretical and technical support for APMM in direct-drive applications such as large telescope drive.Based on the analysis of the research status of APMM and flux modulation machine at home and abroad,three new flux modulated APMMs(FM-APMMs)are innovatively proposed by introducing the design idea of flux modulation machine into the topology design of APMM.The proposed FM-APMMs can effectively improve the utilization rate of PMs,and have the advantages of high average torque and low torque ripple.The proposed FM-APMMs are suitable for some low speed and high torque direct-drive applications such as large telescope drive.Furthermore,two new multi-objective optimization design methods based on machine learning algorithm are proposed,which effectively realize the optimization design of structural parameters and performance improvement of two new FM-APMMs.The main research work and achievements of this dissertation are as follows:(1)The background and significance of this research are introduced.The state of the art of APMM and flux modulation machine at home and abroad is reviewed.(2)The design idea of unit machine is adopted to transform the design of APMM into the design of rotary PM machine.Based on finite element(FE)method(FEM),the electromagnetic characteristics of APMM and its corresponding rotary PM machine are compared.The flux modulation principle of FM-APMM is studied based on the analytical models of magnetomotive force and air-gap permeance.The torque fluctuation mechanism of FM-APMM is described.The asymmetric effect of three-phase winding in FM-APMM is analyzed,and a winding cross connection method is adopted to suppress the torque fluctuation caused by the three-phase winding asymmetric effect.The effectiveness of the proposed method is verified by FEM.(3)A single-sided flux reversal APMM(SS-FRAPMM)is proposed by combining the flux reversal machine with APMM.The topology structure,working principle and slot/pole combination of the proposed machine are studied,respectively.A new multi-objective optimization design method based on machine learning algorithm Cat Boost is proposed to optimize the structural parameters.In three aspects of computational accuracy,computational efficiency and computational cost,a comparative study on the surrogate models established by Cat Boost and other algorithms is carried out,and the robustness of the surrogate model established by Cat Boost is also studied.Based on the surrogate model,the genetic algorithm with elite reservation strategy is used to obtain the optimal structure parameters of the proposed machine.The electromagnetic characteristics of the SS-FRAPMM before and after optimization are compared and analyzed.The comparison results verify the effectiveness of the proposed multi-objective optimization design method.(4)A new double-sided(DS)flux reversal APMM(DS-FRAPMM)and new DS biased flux APMM(DS-BFAPMM)are proposed,which effectively improve the torque output capacity of APMM.For the DS-FRAPMM,the topology structure,working principle,slot/pole combination and optimization of structural parameters of the DS-FRAPMM are studied,and the optimal design scheme is determined.The electromagnetic characteristics of the proposed DS-FRAPMM and SS-FRAPMM are compared,which shows that the DS-FRAPMM has higher torque output capacity.For the DS-BFAPMM,the topology structure,working principle,and slot/pole combination of the DS-BFAPMM are studied.A new multi-objective optimization design method based on machine learning algorithm Light GBM is proposed to realize the optimal design of the key structural parameters of the DS-BFAPMM.The electromagnetic performances of the DS-BFAPMM and other three APMMs are comprehensively compared,which shows that the DS-BFAPMM has the advantages of high average torque and low torque ripple.(5)Two prototypes of the proposed SS-FRAPMM and DS-BFAPMM are manufactured,and the experimental testing platform is also built.The basic electromagnetic characteristics of the two prototypes are tested,mainly including the no-load back electromotive force(back-EMF)of phase winding,back-EMF-speed characteristic curve,torque-current angle characteristic curve,output torque,and torque-current characteristic curve.The experimental results are basically consistent with the finite element results,which verify the correctness of the finite element analysis of the proposed SS-FRAPMM and DS-BFAPMM.