Calculation analysis of thermal loss and temperature field of in-wheel motor in micro-electric vehicle

To improve the efficiency and life of in-wheel motor in micro-electric vehicle, thermal loss and temperature field are calculated and analyzed. The mathematical model of thermal loss and temperature field was established, the equivalent model of stator winding was adequately handled, convection heat transfer coefficients was calculated, and the heat distribution of in-wheel motor was analyzed. Winding copper loss, stator and rotor core loss and eddy current loss of permanent magnet were calculated, which were coupled to the temperature field as the heat sources. This paper effectively simplified and dealt with the inner complex radiating coefficient. Three-dimensional finite element model of temperature field was established, and static and transient state temperatures were simulated and analyzed. Overall temperature of the stator region is higher than that of the rotor region. Temperature of stator iron core is basically accord with the temperature of equivalent insulating film, but both are less than the temperature of equivalent winding. The conformity of the measurement results with the final simulation results shows that three-dimensional finite element method is accurate and feasible to analyze thermal loss and temperature distribution of in-wheel motor, which can afford a theoretical basis to optimize the in-wheel motor.