Electromagnetic Thermal Coupling Optimization of Concentrated Winding PM Motor with Auxiliary Teeth for Electric Vehicle

Abstract

The hybrid electric vehicle composed of diesel engine and generator can greatly alleviate the “range anxiety” problem [1]. The concentrated winding PM motor with high power and small volume is adopted for the large transport or mining machinery vehicles. In order to solve the heat dissipation problem of concentrated winding PM motor and realize efficient cooling, the heat dissipation structure of stator core with auxiliary teeth without any additional facilities is introduced [1-4].In this paper, the influence of auxiliary teeth in stator core on concentrated winding PM motor is studied from electromagnetic and thermal aspects. It can be used as an effective scheme for the thermal design of concentrated winding PM motor.Different from the slot type of general motors, a part of the stator core is extended into the slot to form the auxiliary teeth, as shown in Fig. 1. The purpose of adding the auxiliary teeth is to make the heat inside the slot winding have more paths to transfer to the outside. The stator core is mainly divided into three structures, as shown in Fig. 2.Fig. 5 shows the waveforms of the air-gap flux density. Fig. 7 shows the back EMF. The cogging torques are shown in Fig. 8. Fig. 9 shows the flux density contour. Fig. 10 shows a comparison of the torques of the three models. It can be seen the loss change from Fig. 11 and Fig. 12. Fig. 13 shows the change of torque from model 2 to model 3. Fig. 14 and Fig. 15 show the loss changes from model 2 to model 3. Fig. 16 shows the temperature distribution under the rated condition. The actual stator core with auxiliary teeth (Model 2) is shown in Fig. 17(a).In this paper, the influence of the size of stator core auxiliary teeth on concentrated winding PM motor is studied from electromagnetic and thermal aspects. The results show that the auxiliary teeth will weaken the performance of the motor and make the stator temperature drop and the rotor temperature rise. The auxiliary cooling teeth of stator core provide a new guide for the thermal design of concentrated winding PM motor.