Switched reluctance motor drive operating without a shaft position sensor
AssigneeGeneral Electric Company
InventorsTimothy J. E. Miller, James T. Bass
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Abstract
A method and apparatus for operating a switched reluctance motor at high efficiency, without requiring a shaft position sensor, allows dynamic increase of the torque margin as the dwell angle of the phase currents is changed in response to a change in load torque. Average current supplied by the DC link is sensed as a measure of load torque and is used to control the dwell angle.
Claims13
An open loop method of controlling at least one phase in a converter-driven multiphase variable reluctance drive, said method comprising the steps of:
- measuring load torque;
- and
- setting the dwell angle of the phase current supplied by said converter to said one phase according to a relationship which increases said dwell angle in response to an increase in said measured load torque and which decreases said dwell angle in response to a decrease in said measured load torque, whereby said drive is operated near its pullout torque for all normal values of instantaneous load torque.
An apparatus for controlling a converter for supplying at least one phase of a variable reluctance drive, said converter being supplied from a DC link, said apparatus receiving an input frequency signal and comprising:
- current sensing and filtering means for providing a current signal proportional to the average current supplied by said DC link;
- and
- a dwell generator coupled to said current sensing and filtering means and responsive to said input frequency signal and said current signal, said dwell generator providing to said converter firing pulses having a dwell angle determined by said dwell generator in accordance with said current signal.
An apparatus for controlling a converter for supplying at least one phase of a multi-phase variable reluctance drive, said converter being supplied from a DC link, said apparatus receiving an input frequency signal and comprising:
- current sensing and filtering means coupled to said DC link for providing a current signal proportional to the average current supplied by said DC link;
- dwell function means coupled to said current sensing and filtering means and having said current signal as an input, said dwell function means generating a dwell signal;
- and
- a dwell generator coupled to said dwell function means, said dwell generator being responsive to said input frequency signal and said dwell signal for providing firing pulses to said converter, said firing pulses having a dwell angle proportional to the magnitude of said dwell signal.
Dependencies are inferred from the claim text.