An Analytical Model for a Spoke Type Variable Flux Permanent Magnet Motor in No-load Condition

This paper presents an analytical model, for a new spoke type variable flux machine, with AlNiCo magnets, in the no-load condition. This method is based on the solution of a simple magnetic equivalent circuit of spoke type machines. The effect of stator slots on the air gap magnetic flux density is studied and uneven air gap length is modeled. Based on the no-load air gap magnetic flux density, the mean value of torque is calculated. The analytical and finite element design procedure of spoke type variable flux motor are reviewed briefly. Both analytical and finite element models are verified using test results of the prototyped motor and the effect of magnet length on the torque mean value is discussed, as well.