CPC H02P 23/14 (2013.01) [H02P 27/06 (2013.01)] | 15 Claims |
1. A method of control implemented in a variable speed drive for controlling an electric motor during backspin, wherein the method comprises:
determining, by the variable speed drive, a mechanical power value corresponding to power produced by the motor occurring at a backspin speed and an estimated load torque;
determining, by the variable speed drive, a specific electrical losses profile occurring at a motor flux level, wherein the specific electrical losses profile is an electrical losses profile for which electrical losses coincide with the mechanical power value such that little or no excess power is produced by the motor;
determining, by the variable speed drive, a flux reference and a speed reference to be applied to the motor in order for the mechanical power value to coincide with the specific electrical losses profile such that little or no excess power is produced by the motor; and
controlling, by the variable speed drive, the backspin speed of the motor to maintain the coincidence of the mechanical power value with the specific electrical losses profile such that little or no excess power is produced by the motor.
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