Electromagnetic Analysis and Efficiency Improvement of Axial-Flux Permanent Magnet Motor With Yokeless Stator by Using Grain-Oriented Silicon Steel

This article employs grain-oriented (GO) silicon steel in an axial-flux permanent magnet (AFPM) machine to improve its torque and efficiency. Rolling direction of the GO material have been studied to ensure the machine’s main magnetic flux passes through the easy magnetization direction. Based on the study of the electromagnetic characteristics of AFPM machine, GO silicon steel is laminated to form a stator according to a certain lamination direction. The torque and efficiency of the proposed machine with GO material shows an increase in comparison with that of the conventional non-oriented (NO) silicon steel machine under identical conditions. In addition, an equivalent magnetic circuit model is established to illustrate little difference of electromagnetic property under no-load condition for the yokeless stator AFPM using two kinds of silicon steel sheet. Furthermore, a AFPM machine with stator yoke is also established to highlight the superiority of GO in the application of the AFPM machine with yokeless stator.