| The flux modulated permanent magnet machine(FMPMM)has the advantages of high torque density and high efficiency,which has been an appealing choice in many low-speed and direct-drive applications,such as wind power generation,belt transportation and large telescope drive.This dissertation focuses on the research of the dual-stator flux modulated machine with multiple-PM excitation(DS-FMMPMM).DS-FMMPMM adopts the dual-stator structure and the multiple-PM excitation,in which PMs are placed on both the stator and rotor sides,which can effectively improve the torque density,power density,and power factor.Therefore,the research of DS-FMMPMM has the important theoretical significance and engineering application value.In this dissertation,the design method,new machine topology,flux modulation principle,electromagnetic performance analysis and optimization design method of DS-FMMPMM are studied.The main research works of dissertation are listed as follows:(1)The background and significance of this research are introduced.The research status of FMPMM and dual-stator PM machine at home and abroad is reviewed,and the works to be solved and improved are summarized;(2)Research on the design method of dual-stator flux modulated machine(DS-FMPMM).Firstly,the working principle of FMPMM is analyzed,and the design characteristics of FMPMM are summarized from the perspective of rotary/stationary(R/S)design components.By combing the R/S components of FMPMMs,an R/S design method for the DS-FMPMMs with dual-stator and single-rotor is presented.By assigning the different functions and structural forms to the R/S components,various DS-FMPMMs with different PM excitation types and topologies can be designed.The air-gap magnetic field harmonic characteristics of DS-FMPMMs with rotor-PM excitation,stator-PM excitation and multiple-PM excitation are analyzed by using the magnetomotive force-permeability method,and the basic design principle of DS-FMMPMM is given.In addition,the winding design of DS-FMPMM is studied,which includes the selection of winding type,the feasible combination of stator-slot/winding pole-pair and the connection methods of inner and outer armature windings,et al.This research can provide a theoretical basis for the design and analysis of DS-FMMPMM using different R/S design combinations.(3)Design and analysis of new dual-stator flux modulated machines with dual-PM excitation(DS-FMDPMMs).Three typical topologies of DS-FMDPMM based on the R-R-S-R design combination are proposed,and the operation principles of them are analyzed.The selection of slot/pole combination and the influence of critical structural parameters on the torque characteristics are studied.The quantitative electromagnetic performance comparison of the proposed three DS-FMDPMMs is carried out by using finite element method,and the optimal direct-drive candidate among the three machines is found.To further verify its advantages,the electromagnetic performances of the optimal DS-FMDPMM and two existing dual-stator PM machines are compared.The mechanical design and manufacture difficulties of the optimal DS-FMDPMM is discussed,and the solution is provided.In addition,the mechanical stress,temperature rise and PM demagnetization characteristics of DS-FMDPMM are evaluated.Finally,a prototype is manufactured and experimental validation is carried out.(4)Design and analysis of new dual-stator flux modulated machines with triple-PM excitation.Based on the R-S-R-S-R design combination,a new dual-stator flux reversal machine with triple-PM excitation(DS-FRTPMM)is proposed.The working principle of DS-FRTPMM is analyzed from the perspectives of flux variation and bidirectional flux modulation effect.The influences of slot/pole combination and critical structural parameters on the torque characteristics are studied.The electromagnetic performances of DS-FRTPMM under different PM excitations are compared and analyzed by the finite element method,and the contributions of PMs to the torque are quantitatively analyzed by the frozen permeability method.To verify the advantages of the proposed DS-FRTPMM,the electromagnetic performances of the proposed DS-FRTPMM are compared with that of the traditional FRPMM.Moreover,the performances of machines with dual-PM and triple-PM excitations are compared in detail,under which the difference of power factor between them is analyzed,and their relative performance advantages are summarized.(5)Optimization of DS-FMMPMM based on the machine learning technology.To solve the optimization difficulty of DS-FMMPMM causing by the multiple design parameters,a machine learning technique based multi-level optimization method is proposed.Compared with the traditional optimization methods,the proposed optimization method can effectively save the optimization time and improve the optimization efficiency by introducing the machine learning technology.This dissertation takes a DS-FMDPMM as the optimization object to describe the proposed optimization method in detail.The finite element method and experiment are used to verify the effectiveness of the proposed optimization method. |
