Optimal design of the drive motor based on the road condition of the electric vehicle

Abstract

Due to the progressive prevalence of electric vehicles (EV) in the last few decades, more concerns have been focussed on the drive motor efficiency and its manufacturing cost. This article presents an optimisation design method for EV's motor based on road condition to achieve more practical optimisation design. First, the magnetic circuit model of motor is established which can calculate the efficiency map. The correctness of the circuit model can be verified by comparing the calculated map with the testing map. Second, the objective function can be established by considering the feature of New European Driving Cycle (NEDC) cycle road condition into motor conditions and the time proportions for different motor conditions as the weights. Then, the optimisation design for the motor can be carried out by setting constraints of optimisation including the loss limitation, volume, and other geometrical feasibility. Two objective functions with efficiency as the single objective and efficiency–weight as the dual objective are constructed, and the difference between the two objective functions corresponding to the optimisation scheme is analysed at the end. The optimisation method proposed in this article can be employed in the optimal design of the drive motor under any road condition. The designed scheme obtained from optimisation can achieve the best performance in target under whole road conditions, and by weighing the contradiction between material optimisation and thermal design.