Design And Performance Analysis Of Heat Pipe Based Cooling System For Permanent Magnet Synchronous Motors

As an effective means to solve the energy and environmental problems,electric vehicles(EVs)are playing an increasingly important role in the development of the automobile industry,its development and application have been highly valued by governments all over the world.Replacing traditional internal combustion engine vehicles with EVs has promoted the rapid development of permanent magnet synchronous motor(PMSM),and improved the performance requirements of PMSM.As one of the most important factors for the stable operation of PMSM,the heat dissipation capacity of the motor has attracted wide attention while still remains to be properly solved.Aiming at the problem that the temperature at the end winding of PMSM rises too high,in order to solve this problem and extend the insulation life of the winding,3D heat pipes are innovatively applied to connect the end winding and the casing:the condensing section of the heat pipe is embedded in the blind hole of the casing,and the evaporating section is fixed with the winding through insulation material.In order to further optimize the contact condition between the end winding and the heat pipe,reduce the contact thermal resistance and simplify the assembly process,the heat conduction sealant is introduced to fill the gap between the end winding and the casing,the heat pipe can be fixed and the contact area can be increased at the same time.The main research contents and conclusions are as follows:(1)The 2D electromagnetic field simulation model and 3D temperature field simulation model of A02E are established,the loss distribution under various working conditions is analysis by simulation and acts as the heat source of corresponding parts to carry out the temperature simulation.Aiming at the complex and frequently changed working conditions that EV need to face,the influences of cooling water flow rate,cooling water temperature and motor speed/torque on winding temperature rise are studied.(2)The temperature rise test system is built and winding temperature rise performances under different working conditions are tested,the error between the tested data and simulated data of the stable winding temperature is within 5 ~℃,thus the finite element simulation model is accurate enough for practical use.At the same time,the influences of two motor heat dissipation strategies based on heat pipe on the stable running time of motor under peak-load working condition are studied.(3)Research results show that the maximum winding temperature decrease is 23.1 ~℃ when the heat pipe based heat dissipation strategy is optimized by heat conduction sealant,and effectively twofold the stable running time under peak-load condition.The heat pipe based heat dissipation strategy has a maximum temperature decrease of 10.9 ~℃,almost has no influence on the running time under the peak-load condition.It is shown that heat pipe can effectively inhibit the winding temperature rise under rated power,the temperature rise can be further inhibited and the running time under the peak-load condition can be prolonged when the heat conduction sealant is applied to optimize the contact between heat pipe and end winding,this provide a new direction for phase change heat dissipation for PMSM.