Analysis of Passive Low Power Phase Change Heat Dissipation Method for Electric Vehicle Motor
To be published on April 2, 2019 by SAE International in United States
The electric vehicle motor is developing toward high power density, at the same time brings serious temperature rise problem, which affect the motor performance, efficiency, and useful life. Liquid cooling is usually used to solve the problem, but it’s energy consumption is large and the reliability is poor. In order to solve above problems, a heat dissipation method based on a heat pipe is proposed, and the heat pipe cold end is cooled by vehicle facing the wind. The purpose is to improve the reliability and energy efficiency of the motor thermal management system under the condition of ensuring the normal temperature of the motor. Firstly, the motor heating model is established to analyze the position of the high temperature region when the motor is working, and the influence of the motor speed and torque on the temperature rise of the motor. Then the heat transfer model between the motor winding and the heat pipe cold end is established, and the influence of the working condition change of the heat pipe hot and cold end on the motor heat dissipation is studied. Secondly, the motor heat dissipation performance based on the heat pipe under different driving conditions is analyzed. Next, an energy consumption model is established to compare the energy consumption of the heat pipe cooling and water cooling. Finally, taking the permanent magnet synchronous motor as the object, the experimental platform of the motor heat dissipation based on the heat pipe was built to verify the mathematical model. The research results show that the motor winding temperature can be keep at 80°C~95°C based on the heat pipe heat dissipation when the vehicle speed is lower than 60km/h or the slope is lower than 16%. The motor heat dissipation based on heat pipe can provide some new thoughts for the development, reliability and thermal management of high power density motors.