Optimum Design of Sensorless-Oriented IPMSM Considering Torque Characteristics

Abstract

This article presents the design process of a sensorless-oriented interior permanent-magnet synchronous motor (IPMSM) with concentrated winding, based on spatial saliency for the traction motor in electric vehicles. The purpose of the design method is to ultimately achieve both stable rotor position detection and acceptable torque characteristics such as cogging torque and torque ripple. First, the relationship between the sensorless controllability and the electromagnetic parameters is derived through a mathematical method for a design considering sensorless drive of the motor. After describing the evaluating procedure of the sensorless controllability, the effects of the stator chamfer and notch are analyzed to figure out their effectiveness on the sensorless drive. Focusing on the analysis results of the geometric parameters, the improved model is designed through optimization, considering both sensorless controllability and torque characteristics. Response surface methodology (RSM) is used for optimization. Then, the machine characteristics including the sensorless controllability as the simulation results of the prototype and improved model are compared. It was found that the accuracy of the rotor position estimation and torque characteristics are improved simultaneously by means of the optimum design. Finally, the validity of the simulation results is verified by comparison with the test results of the prototype.