Investigation of torque characteristics in a novel permanent magnet flux switching machine with an outer-rotor configuration

This paper comprehensively investigates the torque characteristics of a novel permanent magnet flux switching machine with outer-rotor configuration. Due to the nature of severe magnetic saturations in the machine, it is of particular interest to ascertain the extent of impact of the load conditions on the overall torque output as well as its component parts. The frozen permeability techniques are implemented in finite element analysis to segregate the output torque of the outer-rotor permanent magnet flux switching machine into three parts: cogging torque, reluctance torque and permanent magnet torque. Two dimensional finite element analysis is first employed to reveal the effects of phase current amplitudes and angles on those three torque components as well as the overall torque, while the three dimensional finite element analysis is carried out to further uncover the influences of end effects on the torque characteristics of the machine. Finally, experimental tests on a prototype machine are performed to validate the torque characteristic predictions by finite element analysis.