Trw Limited

Trw Automotive Gmbh

Luis Ayala

David Julian Moule

Albert Schwinn

A method suitable for characterizing a motor, for instance a permanent magnet synchronous motor, includes obtaining a plurality of winding flux linkage values or terminal voltages of the motor, each corresponding to a different combination of phase current magnitude and phase advance. The resultant flux-linkage values or terminal voltages are transformed into the rotor dq reference frame. The flux linkage model is fitted to the one or more dq-axis flux-linkage values or terminal voltages and their linked phase current magnitude and phase advance using a process of parametric optimisation.

Method of characterising a synchronous motor

A method of controlling a motor, for example of an electric power steering system, includes receiving a motor torque demand signal indicative of a torque required from the motor. A current demand signal indicative of the currents to be applied to each phase to meet the torque demand is generated from the motor torque demand signal. One or more operational values from the motor are determined. The current demand signal is set as a function of one or more parameters of the motor obtained by fitting a flux linkage model to the measured operational values. A motor circuit having the permanent magnet electric motor includes a control stage arranged to generate the current demand signal in response to a torque demanded of the motor. A modifying means modifies the magnitude and/or the phase of the current demanded for each phase of the motor by the controller.

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Radolfzell, Germany

Luis Ayala