Low-Speed Flux-Reversal Machines: Pole-Face versus Inset PM Stators

Abstract

This paper introduces, analyzes by FEM, and compares two stator configurations for low-speed flux-reversal machines (FRM): one with pole-face PMs on the stator poles and the other with inset PMs. High torque density (up to 7 N/cm² tangential rotor stress) and low cogging torque (below 3% of rated value) are demonstrated by rotor skewing with sinusoidal current vector control. Comparable torque density and efficiency are obtained with both configurations, but the inset PMs are less vulnerable to demagnetization at large mmf levels.

Keywords:

• electric drives
• flux-reversal machines
• cogging torque