Design And Optimization Analysis Of High Power Density Permanent Magnet Motor For Electric Vehicle

With the development of science and technology and the improvement of people's awareness of environmental protection in recent years,countries have issued the time node for banning the sale of fuel vehicles,and electric vehicles have gradually come into people's sight.About electric vehicle motor and how to improve the power density of the motor is a hot topic of discussion.Permanent magnet synchronous motor(PMSM)has a prominent application prospect in electric vehicles due to its small size,light weight and high output power.The heat dissipation of the motor is the core guarantee for the normal operation.Therefore,this paper conducts in-depth research on the electromagnetic design,structural optimization and cooling structure of the high-power density motor,and designs a high-power density motor that meets the requirements of working conditions and operation.The transmission system of the electric vehicle is analyzed to study the resistance of the dynamics of the electric vehicle.Relevant parameters of the electric vehicle are used to match the required performance parameters of the motor.The basic parameters of motor design are proposed.As for electromagnetic design,how to improve the power density through reasonable design and optimization of the motor structure is a key research problem.Of motor electromagnetic structure design in this paper,from the following aspects: motor with poles and slots and setting up reasonable chute to reduce the cogging torque,high design stator slot and slot depth and the optimization of slit width to reduce the motor loss,good permanent magnet materials and permanent magnet size can make the permanent magnets in the best working point,the structure of the "V" type permanent magnet material utilization can be improved and air gap flux density.And the motor size is optimized on the basis of the principle that the efficiency is basically unchanged.After the optimization,the core loss and eddy current loss are reduced,and the stability of output torque is improved.The improved drosophila-genetic algorithm was used to optimize the motor power density with stator inner diameter,core length and gap width as parameter variables.The increase of output torque increases the power density of the motor.Heat dissipation of motor is one of the key problems of high density motor.The accurate simulation of temperature field plays an important auxiliary role.Therefore,the loss of motor and controller is analyzed.The loss of the motor is calculated by finite element method and the heat dissipation of the motor.It lays a foundation for the subsequent design of cooling water channel.Three different watercourse structures are designed,the temperature field of the watercourse is analyzed by finite element method,and the structure of the controller watercourse is designed.The flow state of coolant in the channel under certain velocity and inlet temperature is analyzed.The optimal channel structure is obtained by combining the temperature field.The selected radial Z-shaped series channel is further optimized.The influence of the number of channels and the flow of coolant on the heat dissipation of the motor is analyzed,and the optimal shell for the heat dissipation of the water-cooled motor is obtained to meet the working requirements of the high-power density permanent magnet synchronous motor.