Study On Temperature Rise Characteristics Of Oil-water Composite Cooling Of Permanent Magnet Synchronous Motor For Vehicles

With the exhaustion of fossil energy,human beings pay more and more attention to the development of clean energy,and will gradually replace fossil energy with new energy such as electric energy,so the traditional fuel vehicles using fossil energy will be gradually replaced by new energy vehicles such as electric energy.The development of electric drive integration will make its energy density increase day by day,which will lead to the temperature of the motor is getting higher and higher.In the future,the overall performance of the motor will also be affected by the heat dissipation capacity of the motor.The performance of the motor will be directly reflected in the design and manufacture of the motor cooling system.Therefore,the key factor in the future development of the motor is how to improve the heat dissipation efficiency of the motor and enhance the cooling effect of the motor,and this method of optimizing the motor cooling method will become one of the important methods to improve the operating life of the motor.The research object of this paper is a vehicle permanent magnet synchronous motor,based on the motor cooling system using the water cooling scheme,and the research is conducted as follows:(1)The new method used in this paper to study the temperature rise characteristics of permanent magnet synchronous motor: the semi-implicit method of moving particles,and the heat transfer theory related to the motor are introduced in detail.The loss principle and calculation formula of each motor are summarized,and the electromagnetic loss of permanent magnet synchronous motor is calculated and analyzed by using software Maxwell,and the simulation calculation results obtain the loss of each component of the motor under four different working conditions,which provides the loss value for the research and calculation of the temperature rise characteristics in the subsequent stage.(2)Establish and simplify models of water-cooled motors and pretreatment them.Based on hydrodynamics and heat transfer,basic assumptions and boundary conditions are proposed.This paper introduces the four working conditions for evaluating the temperature rise performance of the motor,analyzes the temperature rise characteristics of the motor under different working conditions,verifies the simulation results through the temperature rise bench test,and establishes the research method of the motor cooling system under the water-cooled cooling mode.(3)In order to study the design method of oil-water composite cooling of permanent magnet synchronous motor oil-water composite cooling scheme,design the injection pipe using three-dimensional modeling software,establish the oil-water composite cooling motor model,then analyze the permanent magnet synchronous motor cooling system,and study the temperature distribution and temperature rise characteristics of the motor when comparing the water cooling scheme.The research results show that the permanent magnet synchronous motor adopts the oil-water composite cooling scheme for the motor cooling significantly compared with the water cooling scheme,and the heat dissipation performance of the motor is significantly improved,and the heat dissipation capacity of the motor cooling system under this scheme is better.(4)To consider the influence of different boundary parameters and pipeline parameters on cooling effect,and.The parameters such as cooling pipe size change,number of cooling pipe nozzle,cooling oil inlet temperature and cooling oil flow rate are optimized to improve the overall cooling capacity of the motor.The results show that this method improves the cooling capacity of the motor.