Study On Magneto-thermal Coupling And Design Of High Speed Permanent Magnet Drive Motor

As Chinese automobile industry develops rapidly,the high-speed driving motor as the core of power and endurance is also highly anticipated.Among them,the high speed permanent magnet motor has the advantages of high efficiency and high power density,and compared with the traditional motor with the same power,its volume is smaller,higher efficiency,can significantly reduce the quality of the vehicle drive system,improve the operating efficiency of the drive system,has a high research value and a wide range of industrial application prospects.According to the test performance and motor characteristics of new energy vehicles,combined with the matching principle of vehicle dynamics,the research background,advantages and disadvantages of different structural types of permanent magnet synchronous motors at home and abroad were compared,and a rotor structure consisting of a whole cylindrical magnet was proposed.The rotor structure was wrapped by a stainless steel jacket.According to the main technical indexes of high-speed motor for vehicle,the main structural parameters such as the volume of permanent magnetic steel,the outer diameter of rotor core,the inner diameter of stator core,the structural parameters of stator groove and the number of turns of armature winding are determined by finite element software,and the magnetic characteristics such as air gap magnetic density and magnetic induction intensity are analyzed.The magnetization characteristics of stator of high speed motor are studied in two-dimensional electromagnetic field,and a simple calculation model of iron loss is constructed.The analytical data are compared with the iron loss simulated by finite element method,and the results are basically consistent.Based on the calculation theory of motor copper consumption,the winding copper consumption of high-speed drive motor is calculated by finite element method and analytical method respectively.The eddy current loss of high speed permanent magnet drive motor is simulated in transient field.Based on the established two-dimensional model of the motor,the influence of the magnetic pole parameters on the motor performance was analyzed,and the particle swarm optimization algorithm was used to optimize the groove size of the motor,and the reduction of groove torque,iron loss and increase of output power were set as the objectives,and the motor groove size was constrained,the optimization design of the motor was carried out to achieve the reduction of groove torque and iron loss,and the improvement of output torque.The principle of motor heat transfer is analyzed,and based on this theory,the three-dimensional temperature field of the designed motor is calculated by Fluent.Figure out the process of finite element simulation,calculate the heat dissipation coefficient of different parts,use the three-dimensional model to calculate the temperature distribution of different parts of the motor.Air cooling was carried out to obtain the temperature of each part,and the data were compared with the experimental results of the prototype.The data basically agreed with each other.In order to enhance the heat dissipation capacity of the motor and reduce the temperature of the permanent magnet,a water channel is added on the surface of the housing.The actual heat dissipation capacity of the axial water channel,annular multi-parallel water channel and spiral water channel is compared.Meanwhile,the influence of the cross section area of the water channel on the cooling of the motor is studied.Select the length and width size with optimal performance.