Design,Analysis And Control Of A Hybrid Axial Field Flux-switching Permanent Magnet Machine

Hybrid axial field flux-switching permanent magnet(HAFFSPM)machine is a novel axial field hybrid excitation machine,and it incorporates the merits of the axial field flux-switching and hybrid excitation machine.It exhibits short axial length,high torque and power density,flexible flux regulation capacity and wide operation range,which make it suitable for direct drive electrical vehicles.In this dissertation,the keys of the theoretical and technical issues about HAFFSPM machine are deeply and systematically studied,including the electromagnetic design,the structure optimization,the static characteristics,the different topologies,the reduction of the back-EMF harmonics and the cogging torque,and the control strategies of the HAFFSPM machine.Both the simulant and experimental results are given to verify the theoretical analysis.This work lays an important foundation for the further research and application of the HAFFSPM machine in electrical vehicle drive.The research works of this dissertation are as follows:1.The structure characteristics,operation principle and the winding properties of a three-phase HAFFSPM machine are analyzed in detail.The power-size equation of the HAFFSPM machine is deduced,as well as the equation of the relationship among the magneto motive forces generated by the excitation current and permanent magnets and the flux regulation capacity,which lay theoretical base for the design of the HAFFSPM machine.2.Based on the 3-D finite element(FE)method,the static characteristics of the 6/10,6/11,6/13 and 6/14 HAFFSPM machine are investigated,including the field distributions,air-gap flux density,flux linkage at no-load,back EMF,cogging torque,output torque,and flux regulation capacity.The FE analysis results are compared with that of the theoretical analysis,which verifies the correctness of the design theory of the HAFFSPM machine.3.The influence of the design parameters,such as the spilt ratio,stator tooth width,stator middle tooth width,PM thickness,stator yoke thickness,rotor pole width,rotor pole shape angle,on the electromagnetic performance of the 6/10 HAFFSPM machine is analyzed.In overall consideration of the back-EMF,the cogging torque and the flux regulation capacity,the structure parameters of the 6/10 HAFFSPM machine are optimized based on the design of experiments(DOE)method,and the design scheme of the prototype is obtained.4.The HAFFSPM machines with twisted stators,with segmented twisted rotor,and with asymmetric rotor pole are proposed.Under the condition of the constant structure parameters,the electromagnetic characteristics of the three structures are analyzed.In overall consideration of the back-EMF and the cogging torque,the rotor structure parameters and the topology representation variable of the three structures are optimized.The static characteristics of the optimized structures are compared,which verifies the correctness of the proposed structures in improving the machine performance.5.The harmonic current injection into the field windings to decrease the back-EMF harmonics and the cogging torque is proposed and the interaction principle between the injected field current and the fundamental flux linkage is analyzed.The required harmonic current of the field windings for decrease the specific harmonic content of the back-EMF and the cogging torque are deduced.The dynamic simulation model with the harmonic current injection into the field windings are established,which verifies the correctness of the proposed method in decreasing the back-EMF harmonics and the cogging torque.6.The mathematical models of the HAFFSPM machine are built and analyzed both in stator and rotor reference frames.The vector control strategy is studied and the simulation model of the HAFFSPM machine under vector-control is built based on MATLAB/Simulink.The correctness of the mathematical models and the control strategy are proved by the results of the simulation.7.The experimental platform of the control system of the HAFFSPM machine is built.The experimental studied about the HAFFSPM machine under vector-control are done,which validates the design of the HAFFSPM machine and the control strategies and lays foundations for the further studied and industry application of the HAFFSPM machine.