Design And Study Of Permanent Magnet Synchronous In-wheel Motor For Electric Vehicle

Electric vehicles are the main future direction of car research and development,which has broad market prospects.The development of key technology of the electric vehicle drive system will also becomes a hot research.The application of electric vehicles driven by in-wheel motor,can be conductive to lightweighting,integration and rationalization of the structure layout,which is more effective than other forms of electric vehicles.This paper selects the permanent magnet synchronous in-wheel motor for electric vehicle as the research objective.The main conclusions are drawn as follows:(1)According to the electrical performance indicator of the in-wheel motor,motor drive mode and rotor magnetic circuit structure model are analyzed.The surface of the external rotor motor is determined as an electric vehicle in-wheel motor.According to the performance of permanent magnetic materials,the NdFe35 permanent magnet material is determined as the permanent magnet material for the motor.The main dimensions of the motor,the parameters of the permanent magnet and its magnetizing method are examined,the stator model and the stator winding model are established in this paper.(2)The design of the in-wheel motor is optimized based on the quantum genetic algorithm.The optimized design program of the motor is composed based on software Matlab,and 8 designed variables that have great influence on the motor performance are slected.The optimization results show that the optimized motor has has the advantage of less material cost,lower power consumption and high efficiency.(3)Based on the analysis of the permanent magnet synchronous in-motor used in electric vehicle,the results of the no-load magnetic field show that the motor has magnetic leakage phenomenon and magnetic flux density.The results of the rated load magnetic field reveal that the torque and speed fluctuations of the motor are small.Meanwhile,this paper calculates that the rated load iron loss of the motor is 180 W,copper consumption is 790 W,and eddy current loss for permanent magnets is 45 W,the efficiency of the motor is 90.24%,which indicate magnetic circuit design are relatively reasonable and conform the design requirement.(4)A simulation model of electromagnetic heat coupling of in-wheel motor is established.The transient temperature field of the motor under the rated load is analyzed and calculated,and the temperature distribution of the motor are obtained at different times.The results of the load test of the motor show that the efficiency of the motor is 89.22%,which verifies the accuracy of the finite element model and the rationality of the electromagnetic design.The temperature test of the in-wheel motor shows the accuracy of the electromagnetic coupling model and the rationality of the water-cooling effect of motor,which can meet the normal operation of the motor.