Variable speed machine with high power density

摘要

A high power density reluctance motor which is adapted to be supplied with unidirectional power from a converter has a multiphase stator with concentrated full pitch windings and multiple poles. The rotor has segments which constitute flux guides which serve to bend the flux produced by current flowing in a coil winding in a slot of the stator around the slot and back toward the periphery of the rotor, providing maximum inductance when a flux guide of the rotor is aligned with each such slot. Minimum inductance occurs when the flux guides are out of alignment with the slot conducting current and aligned with an adjacent slot, with a substantially linear change in inductance occuring with rotor displacment. The full pitch coils in each phase of the stator and the segmented rotor construction ensures that the entire air gap surface remains active, allowing greater torque to be produced than in a conventional switched reluctance motor and allowing the materials in the motor to work more efficiently under relatively mild electromagnetic stress. The motor can have few as two phases, with a two phase motor being drivable by a converter which has only two transistors switched to provide unidirectional current pulses to the two phases of the motor at the proper times to achieve motoring operation.