A Doubly Salient Doubly Excited Variable Reluctance Motor

Abstract

A new variable reluctance motor is introduced to help solve the energy circulation problems which exist during commutation in conventional variable reluctance motors (VRM's). The new motor design enables the energy stored in the magnetic field to be retained and utilized within the motor, instead of being returned to the source. The operating principles of the motor and associated converters are presented. The analysis shows that by employing both short pitch and full pitch windings, this new motor can eliminate the two problems without extra conductors in the slots. As a result, the new motor has the following important performance advantages over conventional VRM's: (1) It allows a significant improvement in the turn-off process and therefore allows higher speed capacity; (2) it has higher output with the same or higher efficiency with the same output because of the improvement on the turn-off performance and due to the utilization of the trapped energy; (3) the machine can have a higher output with the same power converter because of the improvement of the energy conversion ratio.