Gearing up for the “more electric” aircraft

Gearing up for the “more electric” aircraft

Gearing up for the “more electric” aircraft

Keywords: Aircraft, Electronic equipment and components

Building on over 40 years of experience, Hispano-Suiza, a SAFRAN company, has carved out a leading position as a supplier of electronic equipment for aircraft.

The company offer recognized expertise in the design, development, production and support of electronic engine control (EEC) units for both civil and military airplanes and helicopters.

Most recently, Hispano-Suiza developed an electrical thrust reverser actuation system (ETRASä) for the A380, the first control system of this type for a commercial airliner. In addition, it is a major partner in Europe's Power Optimized Aircraft (POA) research program to build a technology demonstrator of a more electric aircraft, with particular responsibility for the electrical network test rig.

As the center of excellence in power electronics for the SAFRAN group, Hispano-Suiza is developing the electronics technologies needed for tomorrow's onboard systems. The company is in charge of co-ordinating all research within the group on power electronics technologies, by fostering greater technical and industrial synergies.

Its proactive research and technology strategy means that Hispano-Suiza is a key member of a number of French and European research programs designed to improve power electronics components and systems, as well as enhance mechanical, electrical and thermal integration. The company also reports that it is also taking part in the definition of new electrical architectures for both aircraft and engines. Research projects either under way or being negotiated with the European Commission include: Power Optimized Aircraft (POA), More Open Electrical Technologies (MOET), Thermal Management for Military Applications (TARMAC), Power Electronic Components in Harsh Environment (PECHE), and Modular Electrical Network (MODERNE).

The growth of onboard power electronics

One of the main challenges facing the aircraft industry is to simplify onboard power management in order to enhance aircraft performance and operability. State-of-the-art electrical and electronic technologies should help meet this challenge.

Replacing traditional hydraulic and mechanical energy by electricity should lead to substantial savings on propulsion systems, while still meeting three critical needs: safety, reliability and environmental protection.

The new electrical systems simplify the aircraft's network architecture by integrating electrically-driven actuators in the systems to be controlled. These new arrangements make onboard energy distribution more efficient, and therefore, significantly reduce fuel consumption. At the same time, electrical power supports complex functions, such as in-flight reconfiguration, as well as facilitating maintenance and repairs. Maintenance will be easier and less frequent, because of the substantial decrease in the hydraulic distribution circuits number. At the same time, electronic monitoring of onboard equipment will it is believed make troubleshooting much easier, with permanent tracking of system condition and immediate possible fault location.

Market situation

Today's major new aircraft programs, such as the Airbus A380 and Boeing 787, as well as the planned A350, reflect the greatly increased role of electrical equipment and power electronics.

One of the main factors driving the growth of power electronics on commercial jetliners is in fact greatly increased demand for power in the cabin: seat actuators, PC power sockets, in-flight entertainment, etc. – all equaling about 100 W per passenger. The other main factor is the development of power-hungry electrical components, such as actuators rated at 10–30 kW (for flight controls, braking and landing systems, thrust reversers, etc.). The 787 will change to an electrical air conditioning system, plus an electrical engine starting system, all in all requiring about 1.4 MW of onboard power.

This ongoing trend towards the “more electric” aircraft has naturally led Hispano-Suiza to invest in the design and development of these new electrical and electronic technologies to satisfy the needs of its customers, whether aircraft or engine manufacturers.

Hispano-Suiza's experience and expertise in electronic control systems for aircraft

Full authority digital engine control for commercial and military engines

Hispano-Suiza designs, tests and integrates state-of-the-art technologies in its full authority digital engine controls (FADEC) for commercial and military engines. The design of these electronic control units meets stringent dependability criteria, and provides the dynamic performance qualities needed for jet engine control. These units combine real-time software with sophisticated electronic components, and the system is then qualified to cope with the harshest operating conditions:

• •

  temperatures ranging from -55°C to +100°C

• •

  electromagnetic compatibility (from 10 kHz to 40 GHz)

• •

  resistance to lightning, etc.

Hispano-Suiza is a leading supplier of EEC units for commercial aeroengines developing from 18,000 to 115,000 pounds of thrust. We operate through Fadec International, an equal joint venture with BAE Systems, created to develop, qualify, market and support FADEC systems. It supplies these systems for the CFM56-5A/5B/5C, CFM56-7, CF6-80E and GE90 engines.

The latest FADEC 3 gives operators the best tradeoff between advanced technology and economical operation with our present knowledge. FADEC 3 features an optimized design, providing significant advantages in terms of performance and total cost of ownership. Its heavy-duty computing power and memory mean that it is scalable: additional functions can be added with new engine applications. Because of its high performance and modular design the FADEC 3 has been chosen for the CFM56-7B, CF6- 80C2L1F, GE90-115B, GP7200, GEnx, SaM146 and TP400-D6 engines.

Fadec International FADECs have now logged more than 120 million hours of operation on some 3,000 commercial airliners.

It is also an active player in the business and general aviation market, with a FADEC designed for Pratt & Whitney Canada's PW600 family of engines for light jets, rated at 900- 3,000 lb of thrust. This market is estimated at 350-600 aircraft per year. Incorporating Hispano-Suiza's latest technologies, the PW600 FADEC is a dual-channel unit. It facilitates handling and simplified maintenance, while increasing engine efficiency and lowering operating costs. It also has built-in growth headroom. The PW600 engine has already been selected to power the Cessna Mustang Citation and the Eclipse 500.

Working with Snecma, Hispano-Suiza has long-standing experience in the military market. For instance, we supply the EECs for the M53-P2 engine on the Mirage 2000 family of fighters, and the M88-2 engine powering the new Rafale multirole fighter.

It is also developing an improved version of the EEC for the M88-2, called the M88 Type 3, incorporating the latest technological innovations developed for the commercial FADEC 3 unit. The M88 Type 3 will reportedly offer lower cost, combined with higher reliability and operational capabilities.

Other applications for FADEC technology

The technologies developed for FADECs can also be applied to all control electronics for onboard systems, including braking, steering, landing gear deployment and even propeller deicing systems.

Hispano-Suiza supplies the digital steering control unit for Dassault Aviation's new Falcon 7X business jet, along with the braking and steering control unit for the Falcon 2000EX.

ETRASä, a world first

ETRASä – Electrical Thrust Reverser Actuation System – is said to be the first system of this type on a commercial jetliner, in this case the new A380 super- jumbo. ETRASä uses electromechanical actuators (EMA) to open and close the thrust reversers. Developed jointly by Hispano-Suiza and Honeywell, ETRASä is fitted on the nacelles designed and built by Aircelle for both engines being offered on the A380, the Engine Alliance GP7200 and the Rolls-Royce Trent 902.

The main objectives of this new system, developing 35 kW of power, are to reduce the aircraft's overall weight and maintenance costs, while increasing reliability and safety. The ETRASä concept replaces the usual hydraulic energy used to control thrust reversers by electrical energy, eliminating the many hydraulic and pneumatic components and lines and replacing them with lighter, simpler electrical equipment and wires.

Hispano-Suiza is responsible for the development of various electrical and electronic components, including:

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  electric power actuator;

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  transformer-rectifier unit; and

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  high-power electrical harnesses.

All of these items meet their performance and dependability requirements, including simple fault tolerance, and a design guaranteeing the highly unlikely occurrence of “feared events”, such as in-flight deployment. They were all designed to meet the strictest standards, integrating the combined requirements for temperature, vibration, pressure and humidity.

Honeywell is in charge of mechanical parts, including:

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  screw-type linear actuators;

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  flexible transmission shafts;

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  engine brake; and

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  mechanical integration.

The development of ETRASä is a major technological milestone for Hispano-Suiza, and largely benefits from the company's extensive research into advanced power electronics.

The ETRASä system made its successful first flights in August 2004 on a flying test bed. More recently, the first deployment of ETRASä during the landing of the A380 on 4 May is another major program milestone, demonstrating the concept validity and trouble-free system operation.

Certification of ETRASä is planned for January 2006, with the A380 entering revenue service that summer.

Hispano-Suiza's experience in systems integration and more electric network architecture

Partner in POA, Europe's “more electric” aircraft demonstrator program

Launched in January 2002, the POA program is one of the nine technology platforms within the scope of the 5th PCRD European framework research & development program.

The aim of POA is to optimize energy management onboard by developing a more electric-based architecture for engine and aircraft systems. It has set some very ambitious objectives, including reducing non-propulsive power by 25 per cent in certain flight phases, and reducing fuel consumption by 5 per cent, while also decreasing maintenance costs and increasing system reliability and safety.

Aircraft systems validation rig, to integrate and check out “more electric” systems

Drawing on its experiencing in integrating electrical systems, the company have set up the aircraft systems validation rig (ASVR) at its plant in Colombes, near Paris. Installed in premises covering some 600 m², this is an electrical characterization test rig for a modular, scalable onboard network, integrating ten prototype assemblies from European partners (see below). It is fitted with two 500 kW DC motors, simulating the high-pressure and low-pressure shafts on an aircraft engine, controlled by four-quadrant reversible variable speed drives, with the possibility of mechanical coupling.

It is scheduled to start operation by the end of the year. The prototype assemblies will be tested and characterized in line with the POA validation plan, covering performance specifications and electrical power functional and quality requirements. Results of these tests will help verify the expected improvements for the entire aircraft in terms of efficiency, reliability, weight and cost.

The 11 European partners directly involved in the ASVR

1. 1.

   Hispano-Suiza: prime contractor, fuel pump, oil breather;

2. 2.

   Labinal: aircraft wiring;

3. 3.

   Technofan: air recirculation fan;

4. 4.

   University of Kassel: programmable loads;

5. 5.

   SABCA: flight controls;

6. 6.

   Liebherr: flight controls and A/C fan;

7. 7.

   Goodrich: flight controls and 350VDC generator;

8. 8.

   Thales AES: 350VDC starter- generator;

9. 9.

   ECE-Intertechnique: electrical power center;

10. 10.

    FCS: rig command/control system; and

11. 11.

    SENER: risk analysis and planning

Electric fuel pumping and metering system

In the “more electric” aircraft being developed through the European POA program, the fuel pump is driven by an electric motor, instead of the accessory gearbox as in current airplanes. This major design shift paves the way for the development of an innovative control system, the electric fuel pumping & metering system (EFPMS). Controlling the pump speed electrically allows for precise fuel metering without any additional devices. The use of a mass flow meter enhances metering precision. The EFPMS is an autonomous system that communicates with the FADEC via the engine's digital bus.

The EFPMS will be integrated in the aircraft's electrical network, using the ASVR test rig (see previous page). It will also control the fuel supply for the POA engine test stand developed by Rolls-Royce.

Partner in planned MOET program

MOET is a planned European research project, which was submitted by Airbus to the European Commission in July 2005, for inclusion in the 6th PCRD (framework R&D program).

Lasting 3 years, this project aims to define and draw up a new design and development standard for electrical systems and equipment. It will develop standards for both new electrical architectures, including safety and reliability analyses, and for generic power conversion modules. The development of these new tools and methods will also apply to demonstration products, such as the EMA for flight control.

Hispano-Suiza's role in MOET

For the MOET program, Hispano- Suiza will be focusing on the standardization and integration of power electronics components. These components will be used in both the cabin and the non-pressurized environments, as well as for more effective integration of equipment with a “more electric” engine (covering thermal and electromagnetic compatibility aspects).

Part of this work will be handled by SPEC – SAFRAN Power Electronics Center (SPEC).

SAFRAN Power Electronics Center – SPEC

Hispano-Suiza, the center of excellence in power electronics for the SAFRAN group

SAFRAN has named Hispano-Suiza the center of excellence in power electronics for the group, due to its broad capabilities, based on seasoned professionals capable of transforming an order for electrical equipment into a mature product, plus development and production resources designed for new technologies.

Hispano-Suiza combines expertise in electrical engineering, power electronics and systems integration. As leader of the SPEC, the company is specifically tasked with co-ordinating the group companies' own areas of expertise and scientific and technical knowledge to jointly develop the next generation of electrical systems and equipment for both aircraft and engines.

A dynamic leader in the design and production of electrical actuator controls, Hispano-Suiza is developing partnerships to blaze new paths of collaboration with universities and research labs. Our collaboration with these experts aims to increase the efficiency of the network by co- ordinating the research, engineering and development work carried out through national and European programs.

R&D and production resources

Hispano-Suiza reports that it has the resources needed for the development of SPEC, especially a power integration unit based at the company's plant in Réau, near Paris. This team deploys powerful computer-aided modeling, design and simulation systems, along with the machinery and equipment needed for research, development, testing and production engineering.

The ASVR for the electrical network on the POA “more electric” aircraft, located at Colombes, is dedicated to the integration and validation of electrical systems, and the characterization of the aircraft's electrical networks.

Power electronics, a key to the efficient use of electrical energy

Power electronics components allow electrical energy to be used in place of mechanical, hydraulic, or pneumatic energy to carry out various functions on aircraft. It is a differentiating technology, especially suited to engine and equipment control systems, now under development or to be developed in the coming years, in particular: flight control systems, thrust reverser actuation, braking and landing, etc.

Power electronics research focusing on four areas

SPEC is leading power electronics research focusing on four main areas, listed below. Most of this research is being conducted through programs led by the European Union or France's DGAC civil aviation agency.

Thermal management and environment

This research aims to attenuate the stress to equipment caused by electromagnetic interference, pressure, temperature, humidity and vibrations. The impact of high voltage and altitude on wiring is also being studied.

Electrical network: AC and DC network quality

Designed to guarantee the quality and availability of onboard power, without causing any disturbances. The design of this type of network and protection devices encompasses the electrical generation and distribution system, down to the component level.

Electrical drive system architecture

Focusing on increasing the reliability and availability of electrical drive systems, by using dedicated technologies, setting up redundancies, and monitoring equipment health.

High-temperature power electronics component technology and converter integration (impact on reliability)

The reliability of a power electronics unit is limited by that of its main components (IGBT and condensers). Other decisive factors are operating conditions and temperature. The aim of this research is to optimize the heat exchange between the component and its environment, in relation to volume and weight.

Industrial sites

Hispano-Suiza has four main industrial sites, two in France, near Paris, one in Peterborough, Canada, and another in Sedziszow, Poland.

Colombes, Northwest of Paris, is company headquarters. Production facilities are dedicated to power transmissions for commercial and military airplane engines, and helicopters. Its activities encompass research, design, development, production, testing, sale and support. Colombes also houses the ASVR, within the scope of the European POA program.

Hispano-Suiza's Réau site, located in the Snecma industrial complex in Villaroche, southeast of Paris, groups the Systems, Hydromechanical and Electrical divisions. They handle research, design, development, production, testing, sale and support of control systems for aircraft engines, as well as electric and electronic systems and equipment. The power electronics lab is located here.

The Peterborough plant, in Ontario, Canada, provides research, design, production, testing, sale and support of electronic control units for business aircraft, and control systems for braking, steering and landing gear.

The Sedziszow plant in Poland manufactures gears and housings for Hispano-Suiza's power transmissions.

Details available from: HISPANO- SUIZA. Website: www.hispano-suiza-sa.com