A new electronically-commutated doubly-salient permanent-magnet small motor

It is aim of the present paper to describe a novel form of electronically commutated small doubly-salient permanent magnet (DSPM) motor for household appliance applications. Its basic structure is similar to that of a switched reluctance motor, except for the presence of a high-energy PM inside the rotor poles. Electromagnetic torque is thereby developed in much the same way as in PM brushless DC motors, but with an important cogging torque component required for holding the rotor stationary when the power supply is switched off. Therefore the motor, even when loaded, is not in danger of being accidentally moved to a new position. It is expected that, by fully exploiting the doubly-salient topology and modern high-energy PM materials, this new small DSPM motor can offer good performance in terms of torque density, efficiency, torque-to-current ratio etc., while retaining a simple, rugged structure amenable to automatic manufacture.