Rotor Geometry Design of Saliency-Based Sensorless Controlled Distributed-Winding IPMSM for Hybrid Electric Vehicles

This paper presents the design process of a sensorless-oriented interior permanent magnet synchronous motor (IPMSM). The motor uses spatial saliency for the position-sensorless traction drive in a hybrid electric vehicle (HEV). The sensorless control consists of two signal-injection techniques to achieve wide-torque-range operation at low speed. Realization of a stable sensorless drive necessitates a design capable of expanding the transition region between the two techniques. This paper describes our proposed design methods that can achieve the self-sensing capability while retaining the required torque-speed capability. Finite element analysis is used to evaluate both the self-sensing capability and the torque-speed capability. Under the restricted specifications of dimensions and requirements, the 350 N·m-36 kW IPMSM is optimally designed for HEV applications. The validity of the proposed design method and the expected drive characteristics are experimentally verified by using the prototype.