past, present, and next steps · november 28-30, 2016 eric j. kline engineering manager ......

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AEROSPACE ELECTRICAL SYSTEMSPAST, PRESENT, AND NEXT STEPS

November 28-30, 2016

ERIC J. KLINEEngineering Manager

Generators & Ram Air Turbines


PAST: A BRIEF HISTORY OF ELECTRICAL SYSTEMS

1

Safran Electrical & Power / Confidential / November 2016 / Overview2


AIRCRAFT ELECTRICAL POWER SYSTEMS BY ERA

• 1903 to 1913 – No electrical power (0 VDC)

• 1913 to 1920 – Battery only (6-12 VDC)

• 1920 to 1933 – External Generators and Battery (12-24 VDC)

• 1933 to 1945 – Internal Generators and Battery (28 VDC)

• 1945 to 1960 – 400 Hz AC, slip ring exciters (120 VAC, 400 Hz)

• 1960 to 1976 – CSD, Rotor diodes brushless (120 VAC, 400 Hz)

• 1976 to 1996 – IDG 400 Hz AC systems (120 VAC, 400 Hz)

• 1996 to today – CF, VF, VSCF (120 VAC, 360-800 Hz)

1903 1927 1945 1970 2005


• 1903: Wright Flyer first flight

• Early aircraft had no electric power on board

• No lights, no radio, no entertainment system

• Engines did not require electric power; magnetos for spark ignition

• Control surfaces entirely mechanical

• Flights lasted seconds to minutes… and were dangerous

HISTORY OF AIRCRAFT ELECTRIC POWER: 1903-1913



• Aircraft began to require electricity for radios and lights

• 1913: first use of wireless telegraphy (morse code)

• 1915: first use of 2-way voice communication

• 1916: Marconi Radio Company started production of ground-to-air radio transmitter/receivers

• 6-12VDC power provided by batteries (charged on ground)

• Battery charge would last length of flight

• Technology advancement driven by WW I



• Innovations increase electrical load

• Battery ignition for engines, radios, lights

• Flights get longer, required generator to re-charge battery

• 12-24 VDC

• Technology fueled by inter-war air transport growth (tourism and air mail)



• 1921: US Army Air Corps bombing demo of USS Alabama.



• 1921: Ram Air Turbine (RAT) generator on MB-2



• 1921: RAT generator on Handley-Page W8B



• 1927: RAT generator on OX-5 Swallow



• 1930: RAT generators Handley-Page HP40



• Engine-mounted generators

• Electric starters

• Aerial Radar

• Required 600V power

• Used Motor-Generator sets to provide high-voltage

• Technology fueled by WW II

• 24-28 VDC batteries

• 120VAC: B-29 drives major changes to electrical system

• Transcontinental capability

• More electric actuators, higher power levels, longer cable runs

• Need for high voltage to reduce current requirements

• 3-phase, 120V, 400Hz AC architecture chosen as optimum

Douglas DC-1

B-17



• Converts 28 VDC to 600 VDC to drive radar loads

• Two machines built on one common shaft

• Lots of added weight just to convert voltage

Douglas DC-1

B-17



• 1945: B-29. First AC electrical system. Set standards still widely in use today.

• 3-phase, 120V, 400Hz AC

• 28 VDC for some loads

• Motor-gen set for high voltage radar load



• Innovations:

• 120V 3-phase AC implementation in large aircraft

• Sundstrand Constant Speed Drive (CSD)

• Technology driven by jet propulsion and Cold War

• Larger aircraft have two power busses: 28 VDC and 120V, 400 Hz AC constant frequency

• Mag-Amp and Carbon Pile voltage regulation

B-29 and B-36



Boeing 707

B-47


• Innovations: oil cooling, hermetic semiconductors, HiperCo50, Kapton, Nomex

• Diodes allow first brushless machines with rotating rectifiers

• Rotating exciters create AC power that is rectified to excite main rotor stage

• Previosly, slip rings were used to excite main rotor stage

• First oil-spray cooled machines

• 2-3x increase in power density

• Technology is driven by the space race and Cold War - miniaturization

• Analog generator control units and voltage regulators


Concord

F-111

KC-135

DC-10


• Business dominated by Sundstrand (later United Technologies) due to CSD (constant

speed drive)

• 4-pole, 2-pole IDG’s

• Analog GCUs common

• First digital GCUs (generator control units)

• Some competition from VSCF for 400 Hz

• Westinghouse did initial 737 power system (late-1960s) with VSCF (variable speed, constant frequency)

• Relied on power electronics, but maturity level was not sufficient

• Boeing eventually replaced with Sundstrand CSD and CF (constant frequency) generators


757

C-17

757


• Rise of variable frequency (VF) systems: 360-800 Hz

• Diminishes monopoly of Hamilton-Sundstrand (United Technologies)

• Re-introduction of VSCF: more capable power electronics

• High voltage DC on military aircraft: 270VDC

• Still safety concerns on commercial aircraft, due to fault detection

• Brushless starter generator (BSG): commutation by power electronics instead of brushes

HISTORY OF AIRCRAFT ELECTRIC POWER: 1996-2016+

Global Express A380

787

VF systems:


• Electric Start

• 100+ kVA brushless starter-generators for engine start and power generation

• Replaces pneumatic start from APU; ducting is heavy, bulky, and difficult to maintain

• Ventilation

• Engine bleed air replaced with electric blowers and compressors

• Increases efficiency and thrust of engines

• Can be reduced during takeoff an

• Actuation: gradual replacement of hydraulic equipment

• ETRAS: Electric Thrust Reverser Actuation System

• Electric-Mechanical and Electro-Hydraulic actuators

• Green Taxi

• APU powers motor on main landing gear wheels.

• 3% saving on total fuel burn; significant reduction in NOx, noise, and engine wear

• Electric Drive Train

• Helicoptor tail rotors, distributed propulsion for VTOL

MORE ELECTRIC AIRCRAFT: 2011+REDUCED WEIGHT, INCREASED EFFICIENCY


SAFRAN AT A GLANCE

2



SAFRAN AT A GLANCE


AN INTERNATIONAL

HIGH-TECHNOLOGY

GROUP

€17.4 BILLION in sales*

€2.1 BILLION in R&D expenditures*,

equal to nearly 12% of

sales

Over 900

INITIAL

PATENTS filed in 2015

€2.4 BILLION in adjusted recurring

operating income*

*2015


SAFRAN CAPABILITIES FOR ELECTRIC PROPULSION


Electrical & Power Systems

Formed in 2013 to address growing focus on aircraft electrification

Distribution, Generation, Starters, Motors, Wiring Systems, System Development

Includes former divisions of Goodrich, Lucas, Lear-Siegler, Jack & Heintz

Aircraft Engines (formerly Snecma)

Includes CFM JV with General Electric

CFM-56, LEAP, Silvercrest, components for GE90

Helicopter Engines (formerly Turbomeca)

Power Units (formerly Microturbo APUs)

Transmissions (formerly Hispano-Suiza)



SAFRAN ELECTRICAL & POWER

COPPER Bird electrical system test facility.


SAFRAN ELECTRICAL & POWER AT A GLANCE


*EWIS: Electrical Wiring Interconnection Systems

(2015 figures)

A WORLD

LEADER IN

ELECTRICAL

SYSTEMS

N°1

WORLDWIDE

FOR EWIS*

and ventilation

systems

A WORLDWIDE

CUSTOMER

SERVICES

NETWORK

N°2

WORLDWIDE

FOR

ELECTRICAL

power generation

~ 14, 000

PEOPLE

IN 12

COUNTRIES

GLOBAL

ENGINEERING

SERVICES

and innovative data &

power interconnection

systems

Comprehensive

product portfolio

covering all on

board electrical

systems


AN UNRIVALLED PRODUCT RANGE

27

GENERATION

> Variable and constant

frequency AC generators

> 2-Pole, high speed APU

generators

> 28VDC Brush and

Brushless DC Start

Generators

Safran Electrical & Power / Confidential / November 2016 / Overview

DISTRIBUTION

> AC and DC distribution

> Secondary AC and DC

Solid State Power

Controller (SSPC)

> Circuit breakers

> Contactors & Relays

ALTERNATE

POWER

> Auxiliary Power Unit

e-APU and MPG (Main

Power Generators)

> RAT (Ram Air Turbine)

product policy from

conventional deploy to

integrated solutions

WIRING

> EWIS processes and

Tools

> All-ATA interface

modeling & simulation

> One-Stop Shop for

configuration control

LOADS

ELECTRIFICATION> Green Taxiing (APU

Supplied) and e-Brake

> Electric Nacelle (eTRAS-

Electrical Thrust Reverser

Actuation System, VFN -

Variable Fan Nozzle, Anti-

Ice functions)

> Electric Engine Start

> Flight Controls EMA

(Electro Mechanical

Actuator)

> Variable frequency fans

INTEGRATION &

CERTIFICATION

> Complete nose-to-tail

electrical power systems

for any size of aircraft

> Integration of a complete

electrical power generation

and distribution system and

certification process

support


SAFRANAIRCRAFT ENGINES

Day/month/year



No. 1 engine

supplier worldwide for mainline commercial jets (over 100 seats)

CFM® –


More than 550customers worldwide

Partnership extended

to 2040

Safran Aircraft Engines & GE, successful partners for over 40 years

50/50 joint companyAll activities are equally split: design,

development, production, sales and support.


CFM56, LEAP® – Combining the best technologies from Safran Aircraft Engines and GE


CFM56-5BCFM56-7BOver 29,000 sold.

LEAP-1ALEAP-1BLEAP-1C15% reduction in CO2 emissions

More than 10,000engines ordered to date

A320

B737

A320NEO

B737MAX

C929

A330

B777

A380

CFM-6GE90GP7200GE’s main partner for large turbofans.

More than 29,000CFM56 enginesdelivered worldwide

GE90The most powerful

aero-engine in the world


SAFRANHELICOPTER ENGINES

Day/month/year


• Turboshaft engines

• Helicoptor and VTOL applications


SAFRAN TRANSMISSION SYSTEMS: A WORLD LEADER IN MECHANICAL POWER TRANSMISSION SYSTEMS

Day/month/year



NEXT STEPS,STANDARDS,ANDCERTIFICATION

3



ELECTRIC PROPULSION ARCHITECTURES


Series

Parallel

All-Electric Battery powered (low energy density limits applications to short flights, unmanned vehicles)

Electricity provided by fuel cell; fuel cell TRL (technology readiness level) not currently sufficient.

Turbo-Electric Engine powered generator provides electric power to motorized propellers

Distributed propulsion where multiple engines are not practical (i.e. X-57 or VTOL applications)

Electric Drive Train Some portion of propulsion provided directly by engine

Distributed propulsion powered via electrical drive train

i.e. Helicoptor tail rotor


STANDARDS, BEST PRACTICES, SAFETY


Power Quality Standards

Exist to simplify system integration for airframers

But also “dumb down” envelope based on sometimes outdated limitations

New standards will be needed for advanced electrical systems

Best Practices for Aerospace Design: SAE ARP4754A

Safety: SAE ARP4761

Allowable catastrophic failure probability for a system: 10-9/flight hr

737 fleet hrs = 13,000 aircraft x 80,000 hr = 109 flight hrs

So a single system can never demonstrate high enough reliability

Plan for redundancy if you hope to certify

Why do RATs exist?

Because there are common fault modes for electrical system: i.e. fuel…

Gimli Glider 1982: 767 ran out of fuel. Glided 100+ miles using 20kW of RAT power for control.

18 incidents of RAT deployment for emergency use in past 30 years


MODERN RAM AIR TURBINE


Uses power in airstream to generate electrical or hydraulic power

Constant rotational speed via centrifugal governor

Power independent of main electrical or hydraulic system

Power independent of fuel system


Thank you!


past, present, and next steps · november 28-30, 2016 eric j. kline engineering manager ......

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