Power converter topology and control scheme for mitigating thermal bowing in gas turbine engines
AssigneeGeneral Electric Company
InventorsPhuc Huynh, John Thomas Garrity, Brian Devendorf
Life of this patent
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Abstract
A gas turbine engine includes a compressor section including a compressor rotor shaft assembly and a permanent magnet alternator (PMA) including a rotor shaft drivingly coupled to the compressor rotor shaft assembly. An accessory unit including a power source and power converter circuit is electrically coupled to the PMA. The power converter circuit is configured to control delivery of current from the power source to the PMA to generate a torque on the rotor shaft that causes rotation of the compressor rotor shaft assembly to mitigate thermal bowing during an engine shutdown phase.
Claims20
A gas turbine engine, comprising:
- a compressor section including a compressor rotor shaft assembly;
- a permanent magnet alternator (PMA) including a rotor shaft drivingly coupled to the compressor rotor shaft assembly, wherein rotation of the rotor shaft causes corresponding rotation of the compressor rotor shaft assembly;
- and
- an accessory unit including a power source and power converter circuit electrically coupled to the PMA, wherein the power converter circuit includes:
- a first plurality of switches connected to a first winding of the PMA and configured to control delivery of current from the power source to the first winding for generating a torque on the rotor shaft;
- and
- a second plurality of switches connected to a second winding of the PMA and configured to control delivery of current from the power source to the second winding for generating torque on the rotor shaft, wherein torque on the rotor shaft causes rotation of the compressor rotor shaft assembly to mitigate thermal bowing during an engine shutdown phase.
A power converter circuit for controlling delivery of current to a permanent magnet alternator (PMA) of a gas turbine engine to mitigate thermal bowing during an engine shutdown phase, the power converter circuit comprising:
- a power source;
- a first H-bridge connected to a first winding of the PMA and configured to control delivery of current from the power source to the first winding, the first H-bridge including a first plurality of switches configured to control a direction of the current delivered to the first winding, wherein delivery of current to the first winding in one of a positive direction or a negative direction is configured to generate torque on a rotor shaft of the PMA;
- and
- a second H-bridge connected to a second winding of the PMA and configured to control delivery of current from the power source to the second winding, the second H-bridge including a second plurality of switches configured to control a direction of the current delivered to the second winding, wherein delivery of current from the power source to the second winding in one of the positive direction or the negative direction is configured to generate torque on the rotor shaft of the PMA.
A method of using a permanent magnet alternator (PMA) to mitigate thermal bowing in a gas turbine engine, the method comprising:
- (a) initiating shutdown of a gas turbine engine;
- (b) delivering current to a first winding of a PMA in a positive direction to rotate a rotor shaft of the PMA in one of a positive rotational direction or a negative rotational direction to set an initial first rotational position of the rotor shaft;
- (c) delivering current to a second winding in the negative direction to rotate the rotor shaft in the positive rotational direction from the initial first rotational position to a second rotational position;
- (d) delivering current to the first winding in the negative direction to rotate the rotor shaft in the positive rotational direction from the second rotational position to a third rotational position;
- (e) delivering current to the second winding in the positive direction to rotate the rotor shaft in the positive rotational direction from the third rotational position to a fourth rotational position;
- and
- (f) delivering current to the first winding in the positive direction to rotate the rotor shaft in the positive rotational direction from the fourth rotational position to a fifth rotational position.
Dependencies are inferred from the claim text.