Variable speed variable reluctance electrical machines.

摘要

A drive system includes a reluctance motor (23), driving a load (24). The motor (23) has stator and rotor poles and magnetising windings for each stator pole. The airgap is small so that saturation occurs during pole overlap, and the poles are constructed so that there is torque overlap between phases as successive phases are energised during rotor rotation. A sensor (25) provides a rotor position input to a reference waveform generator (27). The output of generator (27) is determined by rotor position and is applied to a power converter (29) through a current controller (28). Accordingly the waveform generator establishes a relative magnitude for motor phase current for every position of the rotor during the period of energisation of a motor phase. A further input may be applied to the system to determine the absolute magnitude of the phase current, subject to the waveform pattern established by generator (27). The rotor poles may be skewed to modify the static torque versus rotor angle characteristic of the motor, the skew being between one- quarter and one-half of rotor pole arcuate extent.