| The interior permanent magnet synchronous motor(IPMSM)with multi-segmented skewed poles(MSP)is more and more widely used as electric vehicle(EV)drive motor due to its high power density,high torque density and wide speed range,as well as low cogging torque and low torque fluctuation.The electromagnetic noise of driving motor is one of the main noise sources of EVs.The electromagnetic force generated by the air gap magnetic field acting on the inner surface of the motor stator is the main source of the electromagnetic noise.Therefore,the analysis and optimization of the magnetic field and electromagnetic force of the IPMSM with MSP is of great theoretical and engineering value to solve the electromagnetic noise problem of the IPMSM with MSP of EVs from the source.(1)The analytical modeling and characteristic analysis of no-load air gap magnetic field and electromagnetic force of the IPMSM with MSP are carried out.Firstly,the sub-domain method(SDM)combined with the magnetic equivalent circuit method(MEC)is used to establish the accurate analytical model of the no-load air gap magnetic field,and the Maxwell stress tensor method(MST)is used to establish the analytical model of no-load electromagnetic force.Secondly,the analytical model is used to calculate the no-load air gap magnetic field and electromagnetic force of the prototype,and the spatial order and frequency characteristics of the no-load air gap magnetic field and electromagnetic force are analyzed.Finally,the no-load air gap magnetic field and electromagnetic force are calculated by the finite element method(FEM),and the accuracy of the analytical results is verified.(2)The analytical modeling and characteristic analysis of armature reaction magnetic field and electromagnetic force of the IPMSM with MSP are carried out.Firstly,The SDM is used to establish the analytical model of the armature reaction magnetic field without considering the saturation effect of the rotor magnetic barrier.The virtual magnetic field of the rotor magnetic barrier is introduced,and the accurate analytical model of armature reaction magnetic field considering the saturation effect of the rotor magnetic barrier is obtained by the superposition method.The MST is used to establish the analytical model of armature reaction electromagnetic force.Secondly,the analytical model is used to calculate the armature reaction magnetic field and electromagnetic force of the prototype,and the spatial order and frequency characteristics of the armature reaction magnetic field and electromagnetic force are analyzed.Finally,the armature reaction magnetic field and electromagnetic force are calculated by the FEM,and the accuracy of the analytical results is verified.(3)The analytical modeling and characteristic analysis of the load air gap magnetic field and electromagnetic force of the IPMSM with MSP are carried out.Firstly,the accurate analytical model of the load air gap magnetic field is established by superposing the no-load air gap magnetic field and armature reaction magnetic field,and the analytical model of the load electromagnetic force is established by using the MST.Secondly,the analytical model is used to calculate the load air gap magnetic field and electromagnetic force of the prototype,and the spatial order and frequency characteristics of the load air gap magnetic field and electromagnetic force are analyzed.Thirdly,the load air gap magnetic field and electromagnetic force are calculated by the FEM,and the accuracy of the analytical results is verified.Finally,through the analytical model,the load electromagnetic force under the acceleration condition of the motor is calculated,and the time-frequency characteristics of the unsteady load electromagnetic force are analyzed.The conclusions are as follows.The main spatial order of the air gap magnetic field of the IPMSM with MSP is odd times of the number of pole pairs,and the main frequency is odd times of the fundamental frequency.The main spatial order of the electromagnetic force is even times of the number of pole pairs,and the main frequency is even times of the fundamental frequency.The electromagnetic force of the IPMSM with MSP presents unsteady characteristics under the acceleration condition,and its frequency is related to time and speed.The main frequency are even times of the fundamental frequency on the speed at each time.The air gap magnetic field and electromagnetic force of the IPMSM with MSP are layered along the axial direction of the motor,and the number of layers is equal to the number of rotor segments.The layers are staggered at a certain angle,which is equal to the angle of skewed poles.(4)The experimental research and multi-objective optimization on the IPMSM with MSP are carried out.Through the no-load air gap magnetic field test,no-load back electromotive force test and cogging torque test,the accuracy of analytical model and finite element simulation of no-load air gap magnetic field and electromagnetic force of the IPMSM with MSP is verified.Through the electromagnetic torque test,the accuracy of analytical model and finite element simulation of load air gap magnetic field and electromagnetic force of the IPMSM with MSP is verified.Based on the analytical model and non-dominated sorting genetic algorithm,the structural parameters of a prototype of 8-pole 48-slot IPMSM with MSP for EVs are optimized.Without reducing the electromagnetic torque and efficiency,the amplitude of radial electromagnetic force component with specific spatial order and frequency is minimized. |
PDF Full Text Request