Design improvements for flux switching machines

摘要

There is disclosed herein a design for flux-switching machines having one or more armature windings capable of delivering a controlled torque in any selected direction at start-up, without using a mechanical position sensor. Flux switching machines without sensors are also operable in either direction. The present invention discloses design features for such machines that improve the torque profile of the motor in dependence on the angle. In three-phase machines this delivers high torque and low ripple torque. In single phase flux switching machines, the present invention allows the rotor to be placed at a position where the maximum torque can be delivered in either direction by selection of either positive or negative armature current. Rotor slotting is introduced to produce a low permeability path across the rotor teeth with minimal impact on normal torque producing flux paths. The asymmetry of the stator slots is used to additionally create a stable motor position when significantly excited by field means or armature means. The start of the rotor from such a stable position can be made in either direction. The method is suitable for starting permanent magnet flux switching motors. The present invention allows inexpensive single phase motors to start and rotate in either direction, resulting in improved performance compared to the prior art of three phase flux switching motors.