Basic Investigation of an IPMSM Employing Rotor Skew For Enhancing Output Power Under Field Weakening Control

This paper investigates effects of a step skew structure in an interior permanent magnet synchronous motor (IPMSM) to improve the output power in the field weakening control area. In this paper, effects of the step skew during the field weakening control are evaluated by three-dimensional finite element analysis (3D-FEA) as a basic investigation. On the other hand, 3D-FEA is required to reveal characteristics of skew structures, but it is time-consuming. Therefore, we constructed a design procedure for reducing development term until a suitable skew structure is obtained although 3D-FEA is performed. Additionally, the final model developed based on the constructed design procedure can achieve a large reduction in both total harmonic distortion (THD) and torque ripple under the field weakening control compared to the typical step skew models. Furthermore, it is found that the final model can suppress the voltage and has a possibility to improve the output power, especially in the field weakening control area.