Magnetic Field Prediction of Module-Combined Stator Permanent Magnet Synchronous Motor Based on a Nonlinear Hybrid Analytical Model

Module-combined stator permanent-magnet machines have several independent stator modules and each module can be controlled independently. To predict the magnetic field distribution of module-combined stator permanent-magnet machines accurately under asymmetric conditions, this paper proposes a novel nonlinear subdomain and magnetic equivalent circuit hybrid analytical model. The main novelty of the proposed nonlinear hybrid analytical model is representing nonlinear effect by equivalent current sheets on the edges of slots. Equivalent current densities are calculated from magnetic equivalent circuit and used as boundary conditions in the improved subdomain model. The values of the equivalent current sheets are obtained in an iterative algorithm. The nonlinear hybrid analytical model considering saturation effect can accurately calculate magnetic field distribution and electromagnetic performance even under overload conditions. The finite element analysis is performed to validate the accuracy of the proposed hybrid analytical model. A prototype with three stator modules is manufactured and the experimental results verified these predictions.