Design of a 5-Phase IPM Machine for Electric Vehicles

This paper presents the design of a 5-phase interior permanent magnet (IPM) machine for electric vehicle (EV) applications. The Nissan Leaf IPM machine is chosen as the benchmark system against which two designs are developed, 3- and 5-phase machines. The developed machines utilize the same rotor topology as the benchmark machine and adopt a 60-slot stator configuration to facilitate a short-pitch fractional-slot winding scheme. However, the machine total mass, volume, and copper utilization is maintained the same in all designs. Compared to the 3-phase IPM, the 5-phase design results in increased average torque due to improved winding factor hence improved machine power density while maintaining the same total machine ampere-turns and copper losses to ensure the same thermal performance. The study will discuss the improvement in torque and speed capability and present the comparison in loss and efficiency at the machine base speed.