Investigation of Direct & Quadrature Current Effects on Demagnetization of Flux Switching Permanent Magnet Motors

In recent years flux-switching permanent magnet machines have become popular for industrial applications and research, due to advantages such as robustness, high torque, and power density. However, as permanent magnet motors, their performance is affected by demagnetization. It is known, for example, that armature reactions and temperature increases cause permanent magnet demagnetization that leads to power and torque density reduction in motors. In this paper, partially irreversible demagnetization in an flux-switching permanent magnet motor will be investigated using the time stepping finite element method. In addition, the effects of the d and q - axis currents on this type of demagnetization are evaluated by considering several points on the magnets and comparing the flux density of these points with the flux density of the knee point. It is shown that an increase of the q-axis current component increases the machine's demagnetization tolerance.