Design And Analysis Of Permanent Magnet Synchronous Motor For New Energy Vehicles

Today's energy crisis and environmental pollution problems,energy-saving emission reduction of new energy vehicles has been rapidly developed.Driving motor as a new energy vehicle power source is one of its core technology.The permanent magnet synchronous motor(PMSM)has many advantages,such as high running efficiency,large torque density,wide range of constant power speed regulation and high speed operation.It has been widely used in the field of new energy vehicles.It is very important to design a high efficiency permanent magnet synchronous motor which can meet the requirements of starting,climbing,accelerating and cruising of new energy vehicles.The main work of this paper is as follows:Firstly,the structure of PMSM and the influence of different rotor magnetic circuit structure on the performance of PMSM are introduced.The working principle and steady-state performance of PMSM are analyzed in detail.The control strategy of the constant torque interval and constant power range are analyzed,which is the preparation for motor design and performance analysis.Secondly,the design characteristics of the PMSM are analyzed according to the requirements of new energy vehicles.And the design steps and principles of the PMSM are introduced in detail.Based on the requirements of a new energy vehicle,an 8-pole,48-slot V-shaped PMSM is designed according to the design principle.The parameters of air gap,stator slot width and permanent magnet are analyzed by Ansoft/Maxwell 2D software parameter analysis function.The size of magnetic flux density,the amplitude of back EMF and inductance value of d-axis and q-axis,the influence of the structure parameters on the motor performance is obtained and the key dimension parameters of the motor are determined.The finite element analysis software Ansoft/Maxwell 2D is used to establish the motor model.The simulation experiments are carried out on the no-load,rated load,overload and weak magnetic field of the motor.The feasibility of satisfying the basic requirements of the new motor vehicle is verified.The inductance parameter,torque angle and motor efficiency distribution of the motor are analyzed,and the MAP of motor efficiency is obtained.Finally,based on the analysis of the mechanism of the cogging torque,the method of stator teeth notching in order to weaken the cogging torque of PMSM is introduced.The finite element method is used to analyze the effect of the size and position of the auxiliary slot on the cogging torque.According to the expression of electromagnetic torque of PMSM,the key parameters of permanent magnet arrangement of motor rotor are optimized based on the Taguchi method.The simulation results of the average torque and torque ripple of the motor before are compared before and after optimization.The results of this paper provide a system theory and method to design a high-efficiency PMSM which can meet the requirements of new energy vehicles such as starting,climbing,acceleration and high-speed cruise.The proposed structure optimization method for PMSM can promote its widely application.