On-Load Field Prediction in SPM Machines by a Subdomain and Magnetic Circuit Hybrid Model

In this article, a new subdomain and magnetic circuit hybrid model (SMCHM) is proposed for on-load field prediction in the surface-mounted permanent-magnet machines. Equivalent current sheets are introduced to represent the nonlinearity effect, whose values are obtained by a magnetic circuit (MC) and correlated with boundary conditions in a subdomain model. The number of reluctances in the MC of the proposed model can be selected flexibly according to the nonlinearity effect. Instead of sectorial tooth in the conventional subdomain model, parallel tooth is considered in the proposed model to improve the accuracy. The SMCHM can accurately calculate the flux density distributions and electromagnetic performance considering the heavy nonlinearity effect under the load conditions with fast computation speed. The finite-element analysis is performed to validate the proposed model, which shows an excellent agreement between them. A prototype machine is manufactured to further prove these predictions.