Abstract
At present, temperature control has become one of the key factors to the interior permanent magnet motor design for electric vehicles. Traditionally, a simplified decoupling model is used to analyze the electromagnetic heating and the cooling process for the motor. The temperature distribution on the coupling surfaces is presupposed and a CFD analysis of coolant is conducted to obtain the temperature and the heat transfer coefficient distribution on the heat flux coupling surfaces. The temperature and heat transfer coefficient are then applied into the thermal analysis model of the motor for a steady state thermal analysis. The continuous temperature condition and conservation of energy on the coupling surfaces can't be guaranteed in this way, so the accuracy of the temperature results will be affected. In this paper, a complete coupling analysis interface program is developed for the first time to realize the electromagnetic-thermal-fluid coupling analysis of permanent magnet synchronous motors for electric vehicles, which helps engineers to have a better understanding on the cooling mechanism and to obtain more reasonable temperature distribution of the motor. The comparison of the results between the electromagnetic-thermal-fluid coupling method and the traditional simplified decoupling method are presented to verify the necessity of coupling analysis.
KEYWORDS – Electromagnetic-thermal-fluid Coupling, IPM, Transient Temperature Field, Numerical Simulation, Electric Vehicles