Reducing Cogging Torque in Flux Switching Motors With Segmented Rotor

A flux switching machine with a segmented rotor is an attractive alternative for driving high torque density and high-speed applications. However, a motor doubly salient structure causes torque ripples as well as acoustic noise and vibrations. In this paper, the cogging torque of the motor is analyzed and reduced by imposing notches into the segments. Different numbers and shapes of notch are considered, and their effects on the motor cogging torque, developed torque, and back electromotive force (EMF) are investigated analytically. After optimization of the motor cogging torque, the suitable notch number and shape are introduced. Finite-element analysis is employed to confirm the analytical results. In addition, the finite-element results are compared with the presented experimental results.