초록 ▼

A method and apparatus for executing a no-break power transfer between an electrical power generator powered by an auxiliary power unit (APU) and an electrical power generator powered by an aircraft main engine. The method comprises sending a power transfer command, a load/unload amplitude signal, a

A method and apparatus for executing a no-break power transfer between an electrical power generator powered by an auxiliary power unit (APU) and an electrical power generator powered by an aircraft main engine. The method comprises sending a power transfer command, a load/unload amplitude signal, and a target frequency signal from a bus power control unit to an APU electronic control unit; deriving a calculated load range for the APU at a new load and frequency operating point; and determining if the new load and frequency operating point falls within the calculated APU load range. If within range, a no-break power transfer is initiated; if not within range, a power transfer with momentary interruption is initiated.

대표청구항 ▼

I claim: 1. A method for switching between an auxiliary power unit electrical power generator and a main engine electrical power generator, the auxiliary and main power generators connectable to an electrical bus, said method comprising the steps of: sending a new power source command to a bus powe

I claim: 1. A method for switching between an auxiliary power unit electrical power generator and a main engine electrical power generator, the auxiliary and main power generators connectable to an electrical bus, said method comprising the steps of: sending a new power source command to a bus power control unit; sending a load/unload amplitude signal and a target frequency signal from said bus power control unit to an auxiliary power unit electronic control unit; deriving a calculated load range for the auxiliary power unit electrical power generator; comparing said load/unload amplitude signal with said calculated load range; initiating a no-break power transfer when said load/unload amplitude signal falls within said calculated load range; and initiating a power transfer with momentary interruption when said load/unload amplitude signal does not fall within said calculated load range. 2. The method of claim 1 wherein said no-break power transfer comprises a transfer to the main electrical power generator from the auxiliary power unit electrical power generator. 3. The method of claim 1 wherein said power transfer with momentary interruption comprises a transfer to the main electrical power generator from the auxiliary power unit electrical power generator. 4. The method of claim 1 wherein said calculated load range comprises a function of a power output value for said auxiliary power unit electrical power generator. 5. The method of claim 4 wherein said calculated load range comprises an output frequency for said power output value. 6. The method of claim 1 wherein said step of deriving said calculated load range comprises the steps of: obtaining an auxiliary power unit inlet air pressure reading, obtaining an auxiliary power unit inlet air temperature reading, obtaining an auxiliary power unit exhaust air temperature reading, and obtaining an auxiliary power unit shaft speed reading. 7. The method of claim 6 wherein said step of deriving said calculated load range Thither comprises the step of inputting at least one of said auxiliary power unit inlet air pressure reading, said auxiliary power unit inlet air temperature reading, said auxiliary power unit outlet air temperature reading, and said auxiliary power unit shalt speed reading into an algorithm to produce said calculated load range. 8. The method of claim 7 Thither comprising the step of creating said algorithm from empirical operating data. 9. The method of claim 6 wherein said step of deriving said calculated load range further comprises the step of looking up at least one of said auxiliary power unit inlet air pressure reading, said auxiliary power unit inlet air temperature reading, said auxiliary power unit outlet air temperature reading, and said auxiliary power unit shaft speed reading in an auxiliary power unit load range database to yield said calculated load range. 10. The method of claim 9 further comprising the step of deriving said auxiliary power unit load range database from empirical operating data providing lookup output power values as a function of operating characteristics for said auxiliary power unit electrical power generator. 11. The method of claim 1 wherein said momentary interruption comprises a period of at least 10 milliseconds. 12. A method for transferring between a main engine electrical power generator and an auxiliary power unit electrical power generator to power an aircraft electrical system, said method comprising the steps of: deriving a calculated load range for the auxiliary power unit electrical power generator, said calculated load range being a function of auxiliary power unit electrical power generator operating conditions; comparing said calculated load range with a power requirement signal for the aircraft electrical system; initiating a no-break power transfer between the main engine electrical power generator and the auxiliary power unit electrical power generator when said power requirement signal falls within said calculated load range; and initiating a power transfer with momentary interruption between the main engine electrical power generator and the auxiliary power unit electrical power generator when said power requirement signal does not fall within said calculated load range. 13. The method of claim 12 wherein said step of deriving a calculated load range includes the step of applying said auxiliary power unit electrical power generator operating conditions to an algorithm. 14. The method of claim 13 wherein said algorithm is created from empirical operating data. 15. The method of claim 12 wherein said step of deriving a calculated load range includes the step of utilizing said auxiliary power unit electrical power generator operating conditions in accessing a load range database. 16. The method of claim 15 wherein said load range database is derived from empirical operating data providing lookup output power values as a function of operating characteristics for said auxiliary power unit electrical power generator. 17. A control apparatus suitable for use in an aircraft electrical power system having a main engine electrical power generator, an auxiliary power unit electrical power generator powered by an auxiliary power unit, and a bus power control unit receiving a main engine power signal from the main engine electrical power generator and an auxiliary power unit signal from the auxiliary power unit electrical power generator, said control apparatus comprising: a program file including an algorithm, said algorithm for deriving a calculated load range for the auxiliary power unit from an operating auxiliary power unit inlet air pressure reading, an auxiliary power unit inlet air temperature reading, an auxiliary power unit outlet air temperature reading, and an auxiliary power unit shaft rotational speed reading; and an electronic control unit for receiving a load/unload amplitude signal from the bus power control unit, said load/unload amplitude signal being a function of the main engine power signal and the auxiliary power unit signal, said electronic control unit further for obtaining said operating auxiliary power unit inlet air pressure reading, said auxiliary power unit inlet air temperature reading, said auxiliary power unit outlet air temperature reading, and said auxiliary power unit shaft rotational speed reading, said electronic control unit further for receiving said calculated load range from said program file and for generating a no-break power transfer confirmation signal. 18. A control apparatus suitable for use in an aircraft electrical power system having a main engine electrical power generator, an auxiliary power unit electrical power generator powered by an auxiliary power unit, and a bus power control unit receiving a main engine power signal from the main electrical power generation unit and an auxiliary unit power signal from the auxiliary electrical power generation unit, said control apparatus comprising: a load range database for deriving a calculated load range for the auxiliary power unit from an operating auxiliary power unit inlet air pressure reading, an auxiliary power unit inlet air temperature reading, an auxiliary power unit outlet air temperature reading, and an auxiliary power unit shaft rotational speed reading; and an electronic control unit for receiving a load/unload amplitude signal from the bus power control unit, said load/unload amplitude signal being a function of the main engine power signal and the auxiliary power unit signal, said electronic control unit further for obtaining said operating auxiliary power unit inlet air pressure reading, said auxiliary power unit inlet air temperature reading, said auxiliary power unit outlet air temperature reading and said auxiliary power unit shaft rotational speed reading, said electronic control unit further for receiving said calculated load range from said load range database and for generating a no-break power transfer confirmation signal. 19. The control apparatus of claim 18 wherein said load range database includes empirical data providing lookup output power values as a function of operating characteristics for said auxiliary power unit electrical power generator. 20. An electrical power generation system suitable for use in an aircraft, said system comprising: a main engine electrical power generator powered by a main engine and controlled by a main engine generator control unit; an auxiliary power unit electrical power generator powered by an auxiliary power unit and controlled by a auxiliary power unit generator control unit; a bus power control unit for receiving a main engine power signal from said main engine electrical power generator and further for receiving an auxiliary power unit power signal from said auxiliary power unit electrical power generator; and an auxiliary power unit electronic control unit for monitoring operating auxiliary power unit inlet air pressure, said auxiliary power unit electronic control unit further for monitoring operating characteristics of said auxiliary power unit, wherein said auxiliary power unit electronic control unit comprises a load range database, said load range database including empirical data providing lookup output power values as a function of operating characteristics for said auxiliary power unit. 21. The electrical power generation system of claim 20 wherein said auxiliary power unit produces electrical power at a variable frequency. 22. The electrical power generation system of claim 19 wherein said operating characteristics comprise auxiliary power unit inlet air temperature, auxiliary power unit outlet air temperature, and auxiliary power unit shaft rotational speed. 23. The electrical power generation system of claim 19 wherein said auxiliary power unit electronic control unit comprises a program file, said program file including an algorithm for calculating a calculated load range for said auxiliary power unit. 24. The electrical power generation system of claim 19 wherein said auxiliary power unit electrical power generator is connected to an aircraft electrical bus via a contactor, said contactor controlled by said bus power control unit. 25. A computer readable medium having computer-executable instructions for performing a method for executing a power transfer between an auxiliary power unit electrical power generator and a main engine electrical power generator, wherein said method comprises the steps of: receiving a load/unload amplitude signal and a new power source command via a bus power control unit; deriving a calculated load range for the auxiliary power unit electrical power generator; comparing said load/unload amplitude signal with said calculated load range; sending a no-break power transfer confirm signal to said bus power control unit when said load/unload amplitude signal falls within said calculated load range; and sending a break power transfer confirm signal to said bus power control unit so as to initiate a power transfer with momentary interruption when said load/unload amplitude signal does not fall within said calculated load range. 26. The computer readable medium of claim 25 wherein said calculated load range is a function of auxiliary power unit operating conditions. 27. The computer readable medium of claim 25 herein said calculated load range is derived by utilizing an algorithm. 28. The computer readable medium of claim 27 further comprising a program file containing said algorithm. 29. The computer readable medium of claim 25 wherein said calculated load range is derived by utilizing a load range database including empirical data providing lookup output power values as a function of operating characteristics for said auxiliary power unit electrical power generator. 30. The computer readable medium of claim 29 further comprising said load range database. 31. An aircraft having a main engine and an auxiliary power unit, said aircraft comprising: a main engine electrical power generator connected to the main engine; an auxiliary power unit electrical power generator connected to the auxiliary power unit; a bus power control unit for receiving a main engine power signal from said main engine electrical power generator and further for receiving an auxiliary power unit power signal from said auxiliary power unit electrical power generator so as to produce a load/unload amplitude signal; and an auxiliary power unit electronic control unit for monitoring operating auxiliary power unit operating characteristics and deriving a calculated load range for said auxiliary power unit such that a no-break power transfer may be initiated if said load/unload amplitude signal Thus within said calculated load range. 32. The aircraft of claim 31 further comprising a main engine generator control unit for controlling the main engine electrical power generator. 33. The aircraft of claim 31 further comprising an auxiliary power unit generator control unit for controlling the auxiliary power unit electrical power generator. 34. The aircraft of claim 31 wherein said operating characteristics comprise auxiliary power unit inlet air pressure, inlet air temperature, auxiliary power unit outlet air temperature, and auxiliary power unit shaft rotational speed. 35. The aircraft of claim 31 wherein the auxiliary power unit electronic control unit includes a load range database having empirical data providing lookup output power values as a function of operating characteristics for said auxiliary power unit.