Temperature Field Calculation And Cooling System Design Of Plug-in Hybrid Electric Vehicle Motor

With the intensification of environmental pollution and energy shortage, to develop the New Energy Vehicles that is environmental protection and energy conservation is necessary to realize the sustainable development of the auto industry. Plug-in hybrid electric vehicles bring together the advantages of pure electric vehicles and hybrid electric vehicles. It not only can be driven by the energy stored in the accumulator, but can use the engine to realize a longer driving range. Plug-in hybrid electric vehicles are the best research program of the transition phase to pure electric vehicles, and have a great scientific and practical significance.Motor is the key components to the plug-in hybrid electric vehicles. It has many advantages, such as small volume, high efficiency, high power density, large starting torque. But it has a poor ability for environment heat energy dissipates, which leads to a high temperature rise for the motor, influences on the performance of the insulation materials and the permanent magnet of the motor, as well as goes against the safe and reliable operation of the motor. In addition, it is destroyed when the temperature is much too high. This paper is based on plug-in hybrid electric vehicles with water-cooled permanent magnet synchronous motor to further study the rule of the temperature rise of the motor stator and to optimize the cooling system of the motor.Firstly, according to the method of Bertotti iron loss separation and the Joule-Lenz’s law calculated core loss and copper loss of the motor under rated power, rated speed and rated power, peak speed conditions. Simulated the motor temperature field by CFX software and analyzed the temperature distribution under the two conditions. Then a temperature-rising experimental platform about the motor was constructed. Based on the simulation analysis and the experimental results, Verified the highest temperature rise of the motor within the allowed limit temperature and the accuracy and validity of simulation method. Secondly, based on the linear channel designed the bend channel and fin-type channel according to the Newton cooling formula. Using the simulation method, and through the simulation results of the temperature field, the velocity field and the pressure field of three kinds channel structures, it was found that the fin-type channel structure was better. And then, the dissertation determined the optimal water cooling system from the optimization of the cooling water flow rate of the fin-type channel, as well as the best flow rate was 8L/min. Finally, compared analysis the cooling structure before and after optimization under the condition of rated power, rated speed around the motor highest temperature rise, average temperature rise of windings and stator core. The highest temperature was reduced by 10.76%, the average winding temperature rise was reduced by 8.88%, the average temperature of the stator core was reduced by 17.81%, so that the motor cooling capacity increased significantly after optimization.