Design And Research Of Permanent Magnet Synchronous Motor Under Performance Constraint Of Pure Electric Bus

In recent years,the development of new energy vehicles has always been a hot spot,and pure electric vehicles are an important part of new energy vehicles.Compared with hybrid vehicles and traditional internal-combustion vehicles,pure electric vehicles can achieve truly zero emissions.All the power of pure electric vehicle comes from the driving motor.The design level of the driving motor determines the dynamic performance of pure electric vehicle.In this thesis,the parameters and dynamic performance parameters of a pure electric city bus with the length of 8.2 meters and the maximum mass of 11000 kg are taken as constraints,and an 80 k W non-uniform air-gap permanent magnet synchronous motor satisfying the driving performance requirements is designed as the driving motor and analyzed.Firstly,according to the theoretical formula,based on the basic parameters of the whole vehicle of the pure electric bus,the power,torque and speed required by the bus are analyzed and calculated under the constraints of three dynamic performance indexes,namely,the acceleration capacity,the climbing capacity and the maximum speed,and the design requirements of the driving motor are put forward.According to the design requirements,a PMSM with rated torque of 80 k W is designed as the driving motor.The parameters such as motor material,main size,air gap length,stator and rotor structure are analyzed and selected.A 48 slot 8-pole PMSM with a "V" permanent magnet structure is designed as the motor studied in this thesis.Secondly,by using Ansoft software,the flux density distribution of no-load and load of PMSM is calculated by finite element method;the quadrature axis and direct axis is calculated;the air gap magnetic density waveform,the harmonic content and cogging torque obtained by Fourier decomposition of non-uniform air gap structure and uniform air gap structure are analyzed;The effects of different stator current and current lead Angle on rated torque and maximum torque are analyzed.Finally,the prototype is produced and an experimental platform is built to compare and analyze the experimental value with the previous simulation value to verify the correctness of the theoretical analysis.Through the Motor-CAD simulation software,the dynamic system framework of the pure electric bus is established,and the motor model is established as the simulation model of the whole vehicle to carry out electromechanical matching.The simulation analysis of two typical Chinese urban road working conditions and UDDS working conditions is carried out respectively,and the motor output characteristics of the vehicle climbing are verified.The simulation results show that the dynamic performance of the vehicle meets the design requirements and the method of power system parameter matching is feasible.