Analysis Of Electromagnetic And Temperature Fields Of Axial Flux Permanent Magnet Synchronous Motor With Different Structures

With the proposal of Made in China 2025 plan,the fields of energy-saving and new energy vehicles have received further attention.In this paper,the driving motor for 60 k W electric vehicle is taken as the research object,the electromagnetic analysis is carried out,the magnetic pole topology and waterway types of the motor are studied,the prototype is manufactured,and the motor experiment is carried out to verify the accuracy of simulation.Firstly,the electromagnetic analysis is carried out,and the effects of different topology,pole slot matching,magnetic pole structure,winding type and the number of conductors per slot on the electromagnetic performance of axial flux permanent magnet synchronous motor(AFPMSM)are studied.The magnetic cloud diagrams of the prototype under no-load and rated conditions are compared.Secondly,in order to reduce the eddy current loss of permanent magnets(PMs),the magnetic pole topology of AFPMSM is studied.According to the measured current waveform supplied by converter,the motor loss is calculated,and the results are compared with the motor loss excited by sine wave current.The three-dimensional model of the prototype is established,the theoretical basis,boundary and solution conditions of the simulation analysis are introduced,and the temperature field of the prototype is analyzed to provide a reference for comparison.The PMs are segmented into radial equal length,radial equal volume and circumferential equal volume sections.The electric density and eddy current loss of the segmented PMs in converter power supply are studied.Combined with effect of reducing eddy current loss and comprehensive analysis of economy,the number of PMs segments is optimized.On the basis of the optimal number of segments,considering the influence of the adhesive between the PMs,the temperature fields of three kinds of magnetic pole segmented topologies are analyzed,and compared with the temperature field of the motor when the PMs are not segmented.Thirdly,in order to obtain an efficient cooling structure,the flow velocity,the inlet and outlet pressure difference and the temperature of three cooling structures are compared from the spiral,semi-spiral series and semi-spiral parallel waterways.Through the analysis of cooling effect of the motor and the performance requirements of cooling equipment,the spiral waterway is optimized.Aiming at the structural parameters of the spiral waterway,the analysis including the water injection flow,the axial length and radial length of cross section are carried out,and the influence of different waterway structural parameters on the inlet and outlet pressure difference,the temperature of electromagnetic components and waterway of the motor are obtained.Then,in order to improve the design margin of AFPMSM power density,and the water injection flow and the inlet and outlet cross section are required to remain unchanged.Considering the heat dissipation on the stator and rotor side of the motor and making full use of the axial space of the housing end cover,the waterway cooling structure of the spiral waterway parallel axial Z-shaped waterway(SWPAZW)and the spiral waterway parallel radial Z-shaped waterway(SWPRZW)is proposed.The flow velocity,the inlet and outlet pressure difference and the temperature have compared between these two waterways and the spiral waterway.Finally,the prototype is manufactured and the experimental platform is built to carry out electromagnetic and temperature rise experiments,which verifies the accuracy of the simulation calculation of three-dimensional electromagnetic and temperature field.