Patent ID: 8648555
Filing Date: 2014-02-11
Classification: B60L,H02P,Y02T

Abstract:
1. A method for controlling an electric motor at or near stall operational conditions, the method comprising: detecting a rotational position of a rotor of the electric motor; determining whether a composite torque command is larger than a preset torque threshold for a time interval, the composite torque command convertible into a direct-axis current command and a quadrature-axis current command; determining whether a sensed motor speed of the rotor is less than a preset speed threshold for the time interval at any lower speed of the rotor that approaches stall operational conditions; and adjusting the direct-axis current command and the quadrature-axis current command to obtain a revised direct-axis current command and revised quadrature-axis current command for the time interval if the composite torque command is larger than the preset torque threshold and if the motor speed is less than the preset speed threshold, where the revised current commands vary by the detected rotational position of the rotor to achieve a generally constant shaft torque output.