High torque density permanent magnet brushless machines with similar slot and pole numbers

Abstract The paper describes a theoretical and experimental investigation into the electromagnetic performance of permanent magnet brushless machines having similar slot and pole numbers. Finite element analysis is employed to predict the airgap flux density distribution, the cogging torque and emf waveforms, and the winding inductances. It is shown that such machines exhibit a high torque density and is conducive to fault tolerance. The results are validated on two experimental motors.