Abstract: Determination of an estimated initial angular position of the rotor of an AC motor includes application of voltages corresponding to a high frequency reference signal vector to the stator windings of the motor and production of an estimated initial angular position of the rotor as a function of the resulting q-axis stator current component iq_HF, adjustment of transformation of signal vectors from stationary to rotating coordinates and vice versa using the estimated angular position and production of an adjusted estimated angular position of the rotor as a function of the q-axis stator current component as adjusted.

Abstract: A method and apparatus for control of an alternating current electric motor with field weakening, including setting a required operating point for a motor field voltage component as a function of a difference between actual and required motor field current components, and setting a required operating point for a motor torque voltage component as a function of a difference between actual and required motor torque current components. The method also includes setting a field weakening constituent for the required operating point for the motor field voltage component as a function of a difference between a required operating point and an available value of the motor torque voltage component and as a function of a difference between actual and required motor torque current components.

Abstract: A motor controller for determining a position of a rotor of an AC motor, the motor controller comprises a control input for receiving a control signal, an output for providing a power control signal for controlling power applied to a stator of the AC motor, and an input for receiving a feedback signal representative of the current in the stator. The control input and output are coupled by a reference path, and the input is coupled to the control input by a feedback path. A carrier signal injection element injects a high frequency carrier signal in the reference path at an injection node. The motor controller is arranged to generate the power control signal in dependence on the control signal, the feedback signal, and the high frequency carrier signal. A position determining element generates a position signal representing the position of the rotor in dependence on the feedback signal which includes a carrier signal component comprising rotor position information.

Abstract: Determination of an estimated initial angular position of the rotor of an AC motor includes application of voltages corresponding to a high frequency reference signal vector to the stator windings of the motor and production of an estimated initial angular position of the rotor as a function of the resulting q-axis stator current component iq_HF, adjustment of transformation of signal vectors from stationary to rotating coordinates and vice versa using the estimated angular position, and production of an adjusted estimated angular position of the rotor as a function of the q-axis stator current component as adjusted.

Abstract: A motor controller for determining a position of a rotor of an AC motor, the motor controller comprises a control input for receiving a control signal, an output for providing a power control signal for controlling power applied to a stator of the AC motor, and an input for receiving a feedback signal representative of the current in the stator. The control input and output are coupled by a reference path, and the input is coupled to the control input by a feedback path. A carrier signal injection element injects a high frequency carrier signal in the reference path at an injection node. The motor controller is arranged to generate the power control signal in dependence on the control signal, the feedback signal, and the high frequency carrier signal. A position determining element generates a position signal representing the position of the rotor in dependence on the feedback signal which includes a carrier signal component comprising rotor position information.

Abstract: A method and apparatus for control of an alternating current electric motor with field weakening, including setting a required operating point for a motor field voltage component as a function of a difference between actual and required motor field current components, and setting a required operating point for a motor torque voltage component as a function of a difference between actual and required motor torque current components. The method also includes setting a field weakening constituent for the required operating point for the motor field voltage component as a function of a difference between a required operating point and an available value of the motor torque voltage component and as a function of a difference between actual and required motor torque current components.