Method and system for torque control in permanent magnet machines
AssigneeGM Global Technology Operations LLC
InventorsNitinkumar R. Patel, Brian A. Welchko, Bonho Bae, Steven E. Schulz
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Abstract
Methods and systems are provided for controlling permanent magnet machines. The method includes determining a maximum torque of the PM machine based on an error between a commanded d-axis flux and an estimated d-axis flux of the PM machine, and adjusting a torque command based on the maximum torque. The error associated with a variation between a current temperature and a nominal temperature of the PM machine.
Claims20
A method for controlling a permanent magnet (PM) machine responsive to a commanded d-axis flux and a torque command, the method comprising the steps of:
- determining a maximum torque of the PM machine based on an error between the commanded d-axis flux and an estimated d-axis flux of the PM machine, the error associated with a variation between a current temperature of the PM machine and a nominal temperature of the PM machine;
- and
- adjusting the torque command based on the maximum torque to compensate for the variation.
A system for controlling a permanent magnet (PM) machine responsive to a commanded d-axis flux and a torque command, the system comprising:
- a first processing module configured to estimate a maximum torque of the PM machine for a current operating temperature based on an error between the commanded d-axis flux and an estimated d-axis flux of the PM machine, the error associated with a temperature variation from a nominal operating temperature of the PM machine;
- and
- a second processing module coupled to the first processing module, the second processing module configured to adjust the torque command based on the maximum torque to compensate for the temperature variation.
A drive system comprising:
- a permanent magnet (PM) machine having a first torque limit at a nominal temperature and having a magnet temperature;
- an inverter coupled to the PM machine, the inverter configured to drive the PM machine with an alternating current (AC) voltage, the PM machine producing a current based on the AC voltage;
- and
- a controller coupled to the inverter, the controller configured to determine a second torque limit of the PM machine based on the magnet temperature and further configured to adjust the current based on the second torque limit to compensate for a variation between the magnet temperature and the nominal temperature.
Dependencies are inferred from the claim text.