System and method for in-vehicle resolver alignment
AssigneeFord Global Technologies, LLC
InventorsJonathan Hair, David Crist Gabriel, Elizabeth Rose Bifano, Travis Smith, Arun Ganesan, Brian Khoi-Duy Nguyen
Life of this patent
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Abstract
An electric drive system for a vehicle includes a speed/position feedback device coupled to an electric machine and configured to provide an index pulse. The system further includes an inverter having a line voltage sensor. The system includes a controller programmed to, responsive to the electric machine rotating at a generally constant speed without commanding the inverter, generate a resolver offset from a time difference between a zero crossing of a line voltage and the index pulse and operate the inverter according to the resolver offset.
Claims9
A vehicle comprising:
- a resolver coupled to an electric machine and configured to provide an index pulse;
- an inverter having a line voltage sensor;
- and
- a controller programmed to,
- responsive to the electric machine rotating at a constant speed while not being powered by the inverter, generate an offset for the resolver as a ratio of a time difference between the index pulse and a zero crossing indicated by the line voltage sensor and a period of oscillation associated with periodically sampling the line voltage sensor, and through transformation of three-phase currents to a q-axis torque component and d-axis flux component and transformation of the q-axis torque component and d-axis flux component to a three-phase voltage or current waveform, and
- operate the inverter using the offset.
A method comprising:
- responsive to an electric machine rotating at a constant speed while not being powered by an inverter, generating an offset for a resolver as a ratio of a time difference between an index pulse provided by the resolver and a zero crossing indicated by a line voltage sensor of the inverter and a period of oscillation associated with periodically sampling the line voltage sensor, and through transformation of three-phase currents to a q-axis torque component and d-axis flux component and transformation of the q-axis torque component and d-axis flux component to a three-phase voltage or current waveform;
- and
- operating the inverter using the offset.
Dependencies are inferred from the claim text.