Smart hybrid electric and bleed architecture
An aircraft architecture may be designed to create an optimal balance between electric power and bleed power in order to match or improve current more electric architecture (MEA) performance while simplifying power extraction from the engines as well as simplifying the electrical system. Conventional aircraft architectures may use electric only ECS and cabin pressurization systems (so-called “no bleed” systems). Alternatively, older conventional aircraft may use strictly engine bleed air to provide power for ECS and cabin pressurization systems. The present invention, on the other hand, provides an architecture which may optimize the use of both engine bleed air and MEA designs to provide a system that may be simpler and potentially more reliable and available as compared to conventional aircraft architectures.
1. A hybrid electric and bleed system for a vehicle, comprising:
an environmental control system (ECS) having a pressurization circuit and a cooling circuit, the pressurization circuit providing air near cabin pressure, the cooling circuit rejecting heat and water from the air outside a pressure vessel and the ECS configured to be powered by mechanical power from pressurized bleed air and by electrical power through an electric motor;
an electric system having at least one engine driven starter-generator, at least one auxiliary power unit driven starter-generator, at least one main AC bus, and at least one variable voltage of variable frequency bus, wherein
the main AC bus receives alternating current from the engine driven starter-generator or the auxiliary power unit driven starter-generator in a generation mode;
the variable voltage of variable frequency bus receives variable voltage of variable frequency either from a DC bus through at least one inverter/motor controller or from the main AC bus through at least one matrix converter, and the variable voltage of variable frequency bus supplies power to start the engine driven starter-generator or the auxiliary power unit driven starter-generator.
2. The hybrid electric and bleed system for a vehicle according to claim 1 , wherein the electric architecture further comprises at least one secondary bus.
3. The hybrid electric and bleed system for a vehicle according to claim 2 , wherein the secondary bus receives ground power and is electrically connected to the main AC bus through at least one AC-to-AC power converter.
4. The hybrid electric and bleed system for a vehicle according to claim 1 , wherein the electric architecture further comprises at least one battery.
5. The hybrid electric and bleed system for a vehicle according to claim 4 , wherein the battery may either receive or send power to the DC bus via a DC-to-DC power converter.
6. The hybrid electric and bleed system for a vehicle according to claim 1 , wherein the main AC bus may be a 230 volt AC bus and the DC bus may be a +/−270 volt (540 volt) DC bus.
7. The hybrid electric and bleed system for a vehicle according to claim 1 , wherein the ECS comprises:
a compressor mechanically attached to a turbine;
a motor controlling the rotation of the compressor and the turbine;
a heat exchanger;
a water extraction system; and
a temperature trim air valve.
8. The hybrid electric and bleed system for a vehicle according to claim 7 , further comprising bypass circuits allowing the bleed or mixed air comprising recirculated cabin air mixed with engine bleed air at or near cabin pressure to be cooled by the heat exchanger:
i: without the operation of the motor, compressor and turbine if bleed air pressure is sufficient; or
ii: with operation of the compressor, using motor assistance, if bleed pressure is too low.
9. The hybrid electric and bleed system for a vehicle according to claim 1 , wherein the pressurization circuit receives the engine bleed air from:
a low pressure bleed from an engine at a pressure no more than 5 psi above or less than cabin pressure in cruise operation; and
a higher pressure bleed port.
10. The hybrid electric and bleed system for a vehicle according to claim 9 , further comprising a mixer or an ejector, the ejector having fixed or variable geometry, with the required valves to inject bleed air from a high pressure engine bleed in order to increase the pressure of the engine bleed air delivered to the ECS.
11. The hybrid electric and bleed system for a vehicle according to claim 1 , wherein the vehicle is a commercial aircraft.
12. A hybrid electric and bleed system comprising:
an electric architecture, the electric architecture comprising:
a first and at least a second engine, each having at least one engine driven starter-generator;
at least one APU driven starter-generator;
at least one main AC bus;
at least one DC bus; and
at least one VVVF bus, wherein
the main AC bus receives alternating current from the engine driven starter-generator or the APU driven starter-generator in a generation mode;
the DC bus receives direct current from the main AC bus through at least one AC-to-DC power converter; and
the VVVF bus receives variable voltage of variable frequency from the DC bus through at least one inverter/motor controller and the VVVF bus supplies power to start the engine driven starter-generator or the APU driven starter-generator; and
a bleed architecture, the bleed architecture comprising:
an environmental control system having a pressurization circuit and a cooling circuit, the pressurization circuit providing air near cabin pressure and the cooling circuit rejecting heat and water from the air outside a pressure vessel; and
a compressor configured to be selectively operable by electrical power delivered to an electric motor, mechanical power delivered by pressurized bleed air to a turbine to drive the compressor or a combination of the electrical power and the mechanical power.
13. The hybrid electric and bleed system according to claim 12 , wherein:
the first engine has a first engine first starter-generator and a first engine second starter-generator; and
the second engine has a second engine first starter-generator and a second engine second starter-generator.
14. The hybrid electric and bleed system according to claim 13 , wherein:
the first engine first starter-generator and the second engine first starter-generator power a left-hand side of the electric architecture; and
the first engine second starter-generator and the second engine second starter-generator power a right-hand side of the electric architecture, thereby providing an electric architecture with high dispatch reliability.
15. The electric system according to claim 12 , wherein:
the electric architecture further comprises at least one secondary bus; and
the secondary bus receives ground power and is electrically connected to the main AC bus through at least one AC-to-AC power converter.
16. The electric system according to claim 12 , wherein:
the electric architecture further comprises at least one battery; and
the battery may either receive or send power to the DC bus via a DC-to-DC power converter.
17. The hybrid electric and bleed system for a vehicle according to claim 1 wherein the pressurization circuit receives pressurized ram air from a set of motorized cabin air compressors.