Windmill brake for an auxiliary power unit
AssigneeHamilton Sundstrand Corporation
InventorsDhaval S. Patel, Kyle Ives
Life of this patent
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Abstract
A power generation system for an aircraft. The system includes an auxiliary power unit (APU), an APU generator mechanically linked to the APU, a generator control unit controllably coupled to the APU and an electromagnetic windmilling brake connected to APU generator. The electromagnetic windmilling brake includes a number of switched phase connections equal to a number of phases and the switched phase connections are configured to connect each output phase to an adjacent phase.
Claims20
A power generation system for an aircraft comprising:
- an auxiliary power unit (APU);
- an APU generator mechanically linked to the APU;
- a generator control unit coupled to the APU and configured to the control the APU generator;
- and
- an electromagnetic windmilling brake connected to the APU generator, wherein the electromagnetic windmilling brake includes a number of switched phase connections equal to a number of phases and wherein the switched phase connections are configured to connect each output phase to an adjacent phase of the APU generator when the electromagnetic windmilling brake is engaged;
- wherein each switched phase connection comprises a controllable switch and further comprises a resistor in series with the controlled switch.
A power generation system for an aircraft comprising:
- an auxiliary power unit (APU);
- an APU generator mechanically linked to the APU;
- a generator control unit coupled to the APU and configured to the control the APU generator;
- and
- an electromagnetic windmilling brake connected to the APU generator, wherein the electromagnetic windmilling brake includes a number of switched phase connections equal to a number of phases and wherein the switched phase connections are configured to connect each output phase to an adjacent phase of the APU generator when the electromagnetic windmilling brake is engaged;
- wherein the APU generator includes a permanent magnet generator (PMG) that includes a PMG rotor;
- wherein the generator control unit is configured to apply a braking torque with the electromagnetic windmilling brake until the PMG rotor spins faster than a threshold.
A method for preventing windmilling in an auxiliary power unit (APU) that is operatively connected to an APU generator, the method comprising:
- responding to transitioning the APU from off to on by connecting each output phase of APU generator to an adjacent phase of the APU generator using a switched connection;
- wherein connecting the output phases of the APU generator comprises actively closing a plurality of switches thereby creating an electrical pathway between the output phases,
- wherein connecting the output phases of the APU generator comprises actively closing a plurality of switches thereby creating an electrical pathway between the output phases;
- wherein each electrical pathway includes a resistor in series with a corresponding switch in the plurality of switches.
Dependencies are inferred from the claim text.