Start-up control for an induction motor drive
AssigneeGeneral Electric Company
InventorsPaul M. Espelage, James M. Nowak
Life of this patent
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Abstract
A method of starting an AC motor from any initial speed using open loop control is provided. Sufficient current is provided to the motor so that motor flux can be developed. The frequency provided to the AC motor is varied and the stator frequency at which the motor peak flux occurs is determined. A transition to a control responsive to an external command at approximately the stator frequency at which the peak flux occurred is made.
Claims11
A method of starting an AC motor from any initial speed using open loop central, comprising the steps of:
- providing sufficient current to the AC motor so that motor flux can be developed;
- varying the frequency provided to the stator of the AC motor;
- determining the stator frequency at which motor peak flux occurs;
- and
- transitioning to a control responsive to an external command at approximately the stator frequency at which the peak flux occurred.
A method of starting an AC motor from any initial speed using open loop control, comprising the steps of:
- providing sufficient current to the AC motor so that motor flux can be developed;
- varying the frequency provided to the stator of the AC motor;
- determining the frequency at which the motor peak flux occurs;
- and
- transitioning to closed loop control at approximately the stator frequency at which the peak flux occurred.
A method of starting an AC motor from any initial speed using open loop control, comprising the steps of:
- providing sufficient current to the AC motor so that motor flux can be developed;
- varying the frequency provided to the stator of the AC motor;
- determining when the motor power factor changed from leading to lagging;
- and
- transitioning to a control responsive to an external command at approximately the stator frequency at which the change in power factor occurred.
Dependencies are inferred from the claim text.