Design Of Permanent Magnet Motor For New Energy Vehicles

With the progress of science level,people's lives get a lot of improvement,but the air pollution is becoming more and more serious,and hazy weather seriously affects people's health.As people pay more and more attention to health,people are more and more hopeful that air pollution can be effectively controlled and everyone can enjoy a blue sky and white clouds.Some environmental pollution is from the exhaust gas of cars,and now a new kind of new energy automobile using electricity well meets people's demand for a healthy environment.The new energy automobile do not have the exhaust emissions of fuel cars,because they are powered by electricity.If new energy automobile can be widely used,the harmful particles in the air can be effectively reduced.In the motor system of new energy automobile,the motor is a very important part,The motor working mode of new energy vehicles is different from that of conventional motors which generally work at the rated point,while motors used in new energy automobile have a wide working range.In the design of new energy automobile motor,the characteristics of high efficiency,weak magnetic expansion and high power density should be considered.In this paper,the magnetic circuit structure design of the new energy automobile rotor,the performance of magnetic flux weakening,the high efficiency,the electromagnetic design and temperature rise loss are analyzed,and the work has the mainly aspects:Firstly,analyzed the magnetic circuit structure of the rotor.The performance of the motor is closely related to the rotor magnetic circuit structure of the motor,and four kinds of different rotor magnetic circuit structure were analyzed for their air gap flux density,quadrature-direct axis inductance,electromagnetic torque and reluctance torque etc by the finite element method.The flux weakening capability and torque output capability are analyzed,and the efficiency cloud chart of motors with different rotor magnetic circuit structure is simulated.Through comprehensive comparison,the characteristics of motors with different rotor magnetic circuit structure are obtained,and the types of new energy automobile suitable for motors with different rotor magnetic circuit structure are summarized.The appropriate rotor magnetic circuit structure is selected to meet the performance requirements of the motor to be designed.Secondly,the motor electromagnetic design is studied,the main dimensions of the motor are determined,analyzed the influence of the number of poles on the air-gap magnetic densitywaveform and torque output performance by comparing the different poles motor,and the slot-pole combination is determined.The influence of stator crack ratio on the electrical and mechanical properties,such as electrical load and thermal load,is analyzed.The influence of air gap length on inductance and reluctance torque of ac-dc shaft is analyzed.The influence of permanent magnet size on the weak magnetic expansion speed and torque output of the motor is analyzed.Determined the suitable pole-arc coefficients for the design of the motor.Finally,the temperature rise and loss of the permanent magnet motor are studied.The loss of the motor affects the heating of the motor,and many properties of the motor are affected by the temperature rise of the motor.The finite element simulation method is adopted to complete the analysis and calculation of the loss of the stator-rotor of the motor,and the temperature rise of the motor is finally completed.