Optimization of Traction Motor According to Main Operating Points Determination Methods for High Fuel Economy of Electric Vehicles

Recently, among various studies related to electric vehicles (EVs), studies about improving the fuel economy of EVs have been actively conducted. Since the interior permanent magnet synchronous motors (IPMSMs) are widely used as the traction motor of EVs, the fuel economy of EVs can be improved by performing the optimization of the IPMSM for increasing the efficiency. The conventional optimization case considers the fuel economy of EVs calculated from the efficiency at all operating points (AOPs) of the traction motor. Since the conventional optimization case requires many number of times to perform the vehicle simulation, it is time-consuming. Therefore, this paper proposes two optimization cases of the IPMSM considering the efficiency at main operating points (MOPs) to improve the fuel economy of EVs. Also, two methods for determining MOPs of the traction motor are proposed. First, based on the vehicle simulation, two methods for determining MOPs of the traction motor are explained. Second, the optimization technique is explained, and three optimization cases are carried out. Next, three optimization cases are compared in terms of the fuel economy improvement and the number of times to perform the vehicle simulation. Finally, the superiority of the optimization cases of the traction motor considering the efficiency at MOPs proposed in this paper is confirmed.