Auxiliary power unit control method and system
First Claim
1. A method for controlling a gas turbine auxiliary power unit (APU), comprising:
- detecting an inlet temperature; and
varying an APU shaft speed in response to the inlet temperature to maintain a corrected speed between a minimum mechanical speed and a maximum mechanical speed.
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Accused Products
Abstract
An adjustment method and system for an auxiliary power unit (APU) allows the APU speed to vary based on the inlet air temperature to the APU compressor. The APU is controlled by a control law that allows the APU speed to float within a selected range based on speed and electric power generators phase matching criteria that provides smooth power transfer between the APU and a main engine generator. The specific APU mechanical speed for a given temperature may be determined from a compressor map that identifies the optimum combination of pressure ratio, flow rate and efficiency for a given inlet temperature, and avoids running the APU near mechanical resonant vibration conditions.
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Citations
13 Claims
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1. A method for controlling a gas turbine auxiliary power unit (APU), comprising:
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detecting an inlet temperature; and varying an APU shaft speed in response to the inlet temperature to maintain a corrected speed between a minimum mechanical speed and a maximum mechanical speed. - View Dependent Claims (2, 3, 4, 5, 6, 12, 13)
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7. A method for controlling an auxiliary power unit (APU), comprising:
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detecting an inlet air temperature; calculating a corrected speed from an APU shaft speed and the inlet temperature; and maintaining the corrected speed within a selected optimum region by varying the APU shaft speed based on the inlet air temperature, wherein the APU shaft speed is increased when the detected inlet air temperature increases and wherein the APU shaft speed is decreased when the detected inlet air temperature decreases. - View Dependent Claims (8, 9, 10, 11)
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Specification