Study on the Design of Six-Phase Surface Inset Permanent Magnet Synchronous Generator and Motor Considering the Power Factor and Torque Ripple

In this article, a design of six-phase surface inset permanent magnet synchronous machine (SIPMSM) with the open slots is performed considering the power factor and torque ripple. Because of the reluctance torque component by the q-axis core thickness of rotor, an SIPMSM has the high torque density but the large torque ripple. To overcome the large torque ripple, there are various design methods. In case of SIPMSM with the open slots, the tapering of shoe and the notch of stator and rotor cannot apply the tapering that is applied to magnet, but the torque density and power factor decrease because the linkage flux by the permanent magnet reduces. Therefore, the thickness of q-axis core and tapering magnet has the tradeoff between the performance and the torque ripple. In this article, the characteristic according to the q-axis core thickness and tapering magnet is analyzed based on a finite element analysis (FEA). Furthermore, the optimal design is proposed using the performance map based on the tapering of magnet and q-axis thickness of core. For the design of a basic model, pole-slot combinations are compared with the torque of SIPMSM according to the current phase angle. Considering the performance, the basic SIPMSM is selected for the optimal design. Based on the basic SIPMSM, the optimal design is performed based on the optimal design parameters considering the power factor and torque ripple.