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EP-4742476-A1 - ELECTRIC POWER GENERATION SYSTEM FOR AN AIRCRAFT

EP4742476A1EP 4742476 A1EP4742476 A1EP 4742476A1EP-4742476-A1

Abstract

The present invention belongs to the field of aircraft and, in particular, relates to an electric power generation system for an aircraft and its emergency power solutions. The present invention also relates to an electric power network comprising said electric power generation system, and an aircraft comprising the electric power generation system.

Inventors

  • DE BROUWER, Gabrielle Josephine Christiane

Assignees

  • Airbus Operations, S.L.U.

Dates

Publication Date
20260513
Application Date
20241112

Claims (14)

  1. Electric power generation system (1) for an aircraft (100), the electric power generation system (1) comprising: - at least two Ram Air Turbine (RAT) units (2, 2'), wherein each RAT unit (2, 2') has a respective electrical output; - at least one AC/AC converter (3); - at least two generators (4, 4'), wherein each generator (4, 4') is adapted to be connected to a respective engine (5, 5'), wherein each generator (4, 4') has a respective electrical output; - one respective switching means (6) for each AC/AC converter (3), each switching means (6) being configured for selectively connecting either the electrical output of one generator (4, 4') or the electrical output of at least one RAT unit (2, 2') to the input of the respective AC/AC converter (3); - a control unit (7) configured for commanding the at least one switching means (6) such that, in a situation when all of the engines (5, 5') fail, the control unit (7) commands the at least one switching means (6) to connect the output of at least one RAT unit (2, 2') to the input of the respective AC/AC converter (3).
  2. The electric power generation system (1) according to claim 1, wherein the control unit (7) is further configured for commanding the at least one switching means (6) such that, in a situation when all of the engines (5, 5') fail, the control unit (7) commands the at least one switching means (6) to connect each output of at least two RAT units (2, 2') to the input of the respective AC/AC converter (3).
  3. The electric power generation system (1) according to claim 1 or 2, wherein the control unit (7) is further configured for, when at least one of the engines (5, 5') is operational, commanding the at least one switching means (6) to connect the outputs of the emergency generators (4, 4') being connected to an engine (5, 5') being operational to the input of the respective AC/AC converter (3).
  4. The electric power generation system (1) according to any one of the previous claims, comprising one respective AC/AC converter (3, 3') for each RAT unit (2, 2').
  5. The electric power generation system (1) according to any one of the previous claims, wherein at least one of the at least two RAT units (2, 2') comprises a RAT and a RAT generator directly connected to the RAT.
  6. The electric power generation system (1) according to the previous claim, wherein the RAT generator is of the Variable Frequency Generator type, preferably of the Permanent Magnet Generator type.
  7. Electric power network (10) for an aircraft (100), the electric power network (10) comprising: - the electric power generation system (1) according to any one of the previous claims; and - an emergency electric power distribution network (20) connected with the electric power generation system (1), wherein the emergency electric power distribution network (20) comprises one respective AC emergency power busbar (21, 22) for each AC/AC converter (3, 3'), wherein each AC emergency power busbar (21, 22) is configured for connecting a respective output of an AC/AC converter (3, 3') to at least one respective AC electrical load.
  8. The electric power network (10) according to claim 7, wherein: - the electric power generation system (1) comprises at least two AC/AC converters (3, 3'), and - the emergency electric power distribution network (20) comprises at least two respective AC emergency power busbars (21, 22), one AC emergency power busbar (21, 22) for each AC/AC converter (3, 3').
  9. The electric power network (10) according to claim 8, wherein: - the electric power network (10) further comprises second switching means (31) configured to selectively connect and disconnect one AC emergency power busbar (21) to at least another AC emergency power busbar (22); and - the control unit (7) is further configured for, in a flight condition, commanding the second switching means (31) to connect one AC emergency power busbar (21) to at least another AC emergency power busbar (22) for balancing the power between said at least two AC emergency power busbars (21, 22) based on the power delivered by each of the at least two RAT units (2, 2').
  10. The electric power network (10) according to any one of claims 7 to 9, wherein the emergency electric power distribution network (20) further comprises: - one respective AC/DC converter (23, 24) for each AC emergency power busbar (21, 22), wherein each AC/DC converter (23, 24) is arranged at the output of a respective AC emergency power busbar (21, 22); - at least one respective DC emergency power busbar (25, 26) arranged at the output of each respective AC/DC converter (23, 24), wherein the at least one respective DC emergency power busbar (25, 26) is adapted to connect at least one DC electrical load.
  11. The electric power network (10) according to claim 8 and 10, wherein: - the electric power network (10) comprises: - third switching means (32) configured to selectively connect and disconnect one DC emergency power busbar (25) to at least another DC emergency power busbar (26); and - control means configured for, in a flight condition, commanding the third switching means (32) to connect one DC emergency power busbar (25) to at least another DC emergency power busbar (26) for balancing the power between said at least two DC emergency power busbars (25, 26) based on the power delivered by each of the at least two RAT units (2, 2').
  12. The electric power network (10) according to any of claims 10 or 11, wherein the emergency electric power distribution network (20) further comprises one respective DC/DC converter and one respective storage means (29, 30) for each DC emergency power busbar (25, 26), wherein each respective DC/DC converter is arranged between the output of a respective DC emergency power busbar and the input of a respective storage means (29, 30).
  13. Aircraft (100) comprising the electric power generation system (1) according to any of claims 1 to 6 or the electric power network (10) according to any of claims 7 to 12; wherein the at least two RAT units (2, 2') of the electric power generation system (1) are arranged such that in a retracted position they are housed within the aircraft (100) and in a deployed position they are located outside the aircraft (100).
  14. The aircraft (100) according to claim 13, wherein the electric power generation system (1) or the electric power network (10) is housed within the aircraft fuselage section or the aircraft wing section.

Description

TECHNICAL FIELD OF THE INVENTION The present invention belongs to the field of aircraft and, in particular, relates to an electric power generation system for an aircraft. The present invention also relates to an electric power network comprising said electric power generation system, and to an aircraft comprising the electric power generation system. BACKGROUND OF THE INVENTION Commercial transport jet aircraft typically include two or more primary turbine engines, which are used for the propulsion of the aircraft and also to power various electrical and hydraulic loads on the aircraft. These aircraft also typically include at least one auxiliary power unit (APU), which is often mounted at the rear of the fuselage to generate auxiliary power in addition to or in lieu of the power provided by the primary engines of the aircraft. Accordingly, APUs can be used to provide power to an aircraft when the primary engines are not operational. This may occur, for instance, while the aircraft is awaiting departure at an airport gate. Furthermore, the APUs can also provide temporary power to start the primary engines during normal operations, and/or temporary emergency power during an engine-out condition or other emergency situations. Furthermore, these commercial transport jet aircraft typically also include a Ram Air Turbine (commonly known by the acronym "RAT"), to generate emergency power in addition to or in lieu of the power provided by the primary engines of the aircraft. A RAT is usually connected directly to a dedicated electrical generator, to be used as an electrical power source. Other RAT arrangements are connected indirectly via a hydraulic pump to a dedicated electrical generator, such that the hydraulic pump produces hydraulic power, which is subsequently used to power the electrical generator. A dedicated converter AC/AC is typically connected to the output of the electrical generator of the RAT unit. The function of this dedicated AC/AC converter is to convert an alternating current (AC) input signal coming from the electrical generator output of the RAT unit to an alternating current (AC) output signal, where the output voltage and frequency can be arbitrarily varied and regulated. The RAT is a small windmill-type propeller that, under normal conditions of a flight in an aircraft, is installed stowed in a compartment in the fuselage or wing. When required, the RAT is deployed manually or automatically outside the aircraft to drive either an electric generator, a hydraulic pump, or both installed in the aircraft. During the time between power loss and RAT deployment, aircraft batteries are generally used to power essential instrumentation. The RAT generates power from the airstream by ram pressure due to the speed of the aircraft. In general, modern aircraft only employ a RAT unit in emergency situations, either in the event of a loss of hydraulic systems or following the loss of primary and auxiliary power sources. In the event of a simultaneous failure of both primary and auxiliary power sources, the RAT unit will provide power to vital systems of the aircraft, including flight controls or flight-critical instrumentation, navigation and communication equipment. The provision of a RAT unit is becoming increasingly popular as a vital power emergency source in modern aircraft, as it can provide crucial power support in the event of an emergency, thereby ensuring the safe operation of the aircraft. Nevertheless, it is not without its shortcomings. One disadvantage of a RAT is its complex integration within the aircraft. This is due to the difficult selection of the location of the RAT, which is conditioned by strict aerodynamic requirements. A further disadvantage of a RAT is that it is unable to provide sufficient power to power all the hydraulic and/or electric loads on an aircraft. If a RAT unit is configured to power an excessive number of loads during an emergency, the emergency power system may become overloaded, which may result in the RAT stalling. This can lead to a reduction or even the complete elimination of power to all loads, including those that are most essential for the safe operation of the aircraft during the emergency. Furthermore, the provision of a RAT unit is accompanied by the disadvantage of a hidden failure risk. In other words, due to the fact that the RAT unit does not work on a nominal flight, any failure in a RAT component (e.g., corrosion of a part, wiring degradation, or component wear) could potentially result in an inoperative RAT unit, which would constitute a hidden failure. It is only in an emergency scenario that a hidden fault will be identified when the RAT is required. As a preventative measure, periodic maintenance checks are typically conducted on today's aircraft to verify that the RAT is functioning correctly. However, these checks on the RAT's components to ensure reliability are often time-consuming and labour-intensive. Therefore, there is a need for a s