Study of Boosted Toothed Biased Flux Permanent Magnet Motors

Abstract

In this article, three new toothed biased flux permanent magnet (PM) motors are introduced and studied, each of which has a specific arrangement of excitation (dc field/PM) and flux path (series/parallel). This results in three main structures, namely, hybrid excited toothed slot-PM (HETSPM), toothed biased flux PM (TBFPM) with series flux path, and, finally, toothed biased flux slot PM (TBFSPM) with hybrid flux path. The TBFSPM structure has improved the average torque, torque ripple, and efficiency compared to other stator-PM motors. The HETSPM structure has improved the average torque per PM, and the TBFPM structure features a very low-torque ripple profile compared to other stator-PM motors. All the topologies have shown a good PM demagnetization resistance and lower PM loss compared to other structures. Moreover, a new Carter’s coefficient is introduced to increase the accuracy of harmonic analysis for split-tooth structures by modeling the nonlinear effect of fringing flux with a new transition function, which has increased the accuracy by 20% compared to the traditional approach. The theoretical analyses have been checked by the 2-D finite element method (FEM), and the TBFSPM structure is prototyped and tested to validate the simulation analyses.