Efficiency Characteristics Comparison of Surface and Interior Permanent Magnet Synchronous Machines in Electric Vehicle

The paper analyzes and compares the efficiency characteristics of the Surface Permanent Magnet Synchronous Machine (SPMSM) and the Interior Permanent Magnet Synchronous Machine (IPMSM) which applied in the electric vehicle (EV). The loss coefficient is introduced and employed to study the mechanism between the efficiency characteristics and the parameters which have great influence on the loss distribution. The driving cycle efficiency is analyzed and compared to evaluate the application in the EV. The conclusions obtained can be used to guide the initial design to match the object load characteristic.