A study on irreversible permanent magnet demagnetization in flux-reversal machines

Flux-reversal machine (FRM) is a new doubly-salient stator-permanent magnet (PM) machine with flux linkage reversal in the stator concentrated windings. The simple structure makes it cost effective and suitable for mass production. Also, the FRM has permanent magnets parallel to the stator magnet flux lines and thus is much more difficult to demagnetize. However, in actual application fields such as factory automation and a home appliance, the FRMs adopt permanent magnets with a low intrinsic coercivity and a narrow thickness. In this paper, we especially concentrate on the irreversible demagnetization characteristic of the permanent magnet. To analyze the characteristics of the FRM, a two-dimensional finite-element method (2D FEM) considering the nonlinear analysis of the permanent magnet is used.