A NASA PERSPECTIVE ON ELECTRIC PROPULSION …machineroadmap.ece.illinois.edu/files/2016/04/Madavan.pdf · − Hybrid-electric propulsion system concept (Rolls Royce, Boeing, GA Tech)

National Aeronautics and Space Administration 1

National Aeronautics and Space Administration

A NASA PERSPECTIVE ON ELECTRIC PROPULSION TECHNOLOGIES FOR COMMERCIAL AVIATION

Nateri Madavanand James Heidmann,, Cheryl Bowman, Peter KascakAmy Jankovsky, and Ralph Jansen

Advanced Air Transport Technology ProjectNASA Advanced Air Vehicles Program

Workshop on Technology Roadmap for Large Electric MachinesUniversity of Illinois Urbana-ChampaignApril 5-6, 2016

2Advanced Air Transport Technology ProjectAdvanced Air Vehicles Program

Background


NASA Aeronautics Vision for the 21st Century

On Demand Fast

TRANSFORMATIVE

Intelligent Low Carbon

SUSTAINABLE

Safety, NextGenEfficiency, Environment

GLOBAL

A revolution in

sustainable global air

mobility


Aviation’s Grand Challenge

CO

2E

mis

sion

s

Wit

h Im

prov

emen

t

Additional Technology Advancement

Carbon neutral growth

and Low Carbon FuelsCarbon overlap

By 2050, substantially reduce emissions of carbon and oxides of nitrogen and contain objectionable noise within the airport boundary


Advanced Air Transport Technology Project

Explore and Develop Technologies and Concepts forImproved Energy Efficiency and Environmental Compatibility forFixed Wing Subsonic Transports

Evolution of Subsonic Transports Transports

1903 1950s1930s 2000s

DC-3 B-787B-707

§ Early stage exploration and initial development of game-changing technologies and concepts

§ Commercial focus, but dual use with military§ Gen N+3 time horizon § Research aligned with two NASA Aeronautics strategic R&T thrusts § Research vision guided by vehicle performance metrics developed for

reducing noise, emissions, and fuel burn

6Advanced Air Transport Technology ProjectAdvanced Air Vehicles Program Analysis based on FAA US operations data provided by Holger Pfaender of Georgia Tech

Fuel Consumption by Aircraft Size Class

40% of fuel use is in 150-210 pax large single aisle class87% of fuel use is in small single-aisle and larger classes ( >100 pax) 13% of fuel use is in regional jet and turboprop classes


Hybrid-electric propulsion for commercial aviation


The Case for Hybrid Electric Propulsion

• Lower emissions, lower noise, better energy conservation, and more reliable systems

• Considerable success in development of “all-electric” light GA aircraft and UAVs

• Advanced concept studies commissioned by NASA for the N+3/N+4 generation have identified promising aircraft and propulsion systems

• Industry roadmaps acknowledge need to shift to electric technologies • Creative ideas and technology advances needed to exploit full potential• NASA can help accelerate key technologies in collaboration with other

government agencies, industry, and academia


Four Cardinal Electric Propulsion Architectures

ParallelHybrid

Fuel Fan

TurbofanElectric Bus

MotorBattery

1 to ManyFans

Electric BusMotor(s)

BatteryAllElectric Turboelectric

Fuel

Turboshaft

Generator

Electric BusDistributed

Fans

Motor

Motor

Series Hybrid

Fuel

Turboshaft

Generator

Electric Bus

Battery

DistributedFans

Motor

Motor


Lower Carbon Designs: Reduce combustion-based propulsive power (and emissions) using electric motors and/or on-board “clean” energy storage

Distributed Propulsion: Allows effective increase in fan by-pass ratio through distributed propulsors

Boundary Layer Ingestion: Allows propulsion systems to energize boundary layers without distorted flow entering turbine core

Wing Tip Propulsors: Allows energization of wing tip vortices without penalty of small turbomachinery

Hybrid Electric Propulsion Enables Wide Range of Configuration Options

Common Technology Requirement: Increased efficiency and specific power in electric drive systems, thermal management systems, power extraction, and/or energy storage


NASAN3X

Airbus/Rolls-RoyceeThrust

ESAero ECO-150

Future Turboelectric Aircraft Concepts


NASA HEP perspective and challenges


The NASA Perspective• Develop and demonstrate technologies that will revolutionize commercial

transport aircraft propulsion and accelerate development of all-electric aircraft architectures

• Enable radically different propulsion systems that can meet national environmental and fuel burn reduction goals for commercial aircraft

• Focus on future large regional jets and single-aisle twin (Boeing 737-class) aircraft for greatest impact on fuel burn, noise and emissions

• Focus on hybrid-electric technologies since all-electric propulsion for large transports unlikely in N+3 time horizon

• Research horizon is long-term but with periodic spinoff of technologies for introduction in aircraft with more- and all-electric architectures

• Leverage investment in efficiency improvements in the energy sector

• Power system development for terrestrial applications does not adequately address weight or thermal management requirements for aviation applications


Hybrid Electric Propulsion Technology Projections

5 to 10 MW

• Hybrid electric 50 PAX regional• Turboelectric distributed propulsion 100 PAX regional• All-electric, full-range general aviation

• Hybrid electric 100 PAX regional• Turboelectric distributed propulsion 150 PAX• All electric 50 PAX regional (500 mile range)

• Hybrid electric 150 PAX• Turboelectric 150 PAX

>10 MW

Powe

r Lev

el fo

r Ele

ctric

al P

ropu

lsion

Today 10 Year 20 Year 30 Year 40 Year

Projected Timeframe for Achieving Technology Readiness Level (TRL) 6• Turbo/hybrid electric

distributed propulsion 300 PAX

• All-electric and hybrid-electric general aviation (limited range)

Technologies benefit more electric and all-electric aircraft architectures:

• High-power density electric motors replacing hydraulic actuation

• Electrical component and transmission system weight reduction

kW class

1 to 2 MW class

2 to 5 MW class


Timeline for Electric Machine ApplicationMachine Size Depends on Electrification Architecture

SuperconductingNon-cryogenic 100 kW 1 MW 3 MW 10 MW 30 MW

19 Seat2 MW Total Propulsive Power


9 Seat 0.5 MW Total Propulsive Power

50-250 kW Electric Machines

0.1-1 MW Electric Machines

50 Seat Turboprop 3 MW Total Propulsive Power



1-11 MW Electric Machines

3 -30 MW Electric Machines

Largest Electrical Machine on Aircraft

50 Seat Jet12 MW Total Propulsive Power


1.5-2.6 MW Electric Machines


Leftsideofeachpowerrangebaristhesmallestmotor thatyields overallaerodynamicefficiencyincreaseforapartiallyelectrifiedairplane

Rightsideisthesizeofageneratorforatwinturboelectricsystemforafully electrifiedairplane

What Technologies are Required?Depends on vehicle size and range

It is a vehicle optimization problem

• Better energy storage opens up more options for distributed propulsion or all-electric

• Better electric machines open up all options • Better power grids are required for anything in the MW level• Better materials and subcomponents enable better electric machines

and power systems• Systems level studies and tests are required to pin down key

performance parameters for each technology


Hybrid Electric Propulsion Challenges

• Weight• Weight• Heat• Safety• Reliability• Certification


Gas Turbine Engines… The Past 50 Years

Thrust to Weight

130

120

110

100

90

801940 1960 1980 2000

Engine Noise(cum db’s)

8

6

4

2

01940 1960 1980 2000

0.9

0.8

0.7

0.6

0.5

0.41940 1960 1980 2000

Fuel Efficiency(SFC)

Flight Safety(accidents per MFH)

20

15

10

5

01940 1960 1980 2000

25

90%Improvement 350%

Increase

35 dbDecrease

45%Improvement

From: Dale Carson, GE Aviation (EAA Electric Flight Symposium, July 2011)


NASA AATT hybrid-electric propulsion research and technology investments


NASA AATT HEP Technology Investments


High Efficiency, High Specific Power Electric Machines

• Develop both conventional (near-term) and cryogenic, superconducting (long-term) motors

• Design and test scalable high efficiency and power density (96%, 8 hp/lb) 1 MW non-cryogenic motor for aircraft propulsion in collaboration with

• Ohio State U • U of Illinois, UTRC, Automated Dynamics

• Reduce AC losses and enable thermal management for SC machines: models and measurement techniques, SC wires, flight-weight cryo-coolers

• Design and test fully superconducting electric machine test at 1 MW design level in FY17-18

• Collaboration with Navy, Air Force, Creare, HyperTech, Advanced Magnet Lab, U of FL

• Detailed concept design completed of 12MW fully superconducting machine achieving 25 hp/lb

• Develop materials and manufacturing technologies

Fully superconducting motor

U of Illinois Design

Ohio State U Motor Design


TRL 2-3 Motor design analysis for 1 MW size predicts performance feasibility

Development Potential for Electric Machines

NRA Contract: TRL 4 Demo by 2018 for 1 MW machine with 13 kWkg (8hp/lb), 96% efficiency (triangle)

Synchronous reluctance motor with SOA materials (open circle), with advanced materials (solid circle)

Interior Permanent Magnet motor with SOA materials (open square), with advanced materials (solid square)

Launchpoint UAV

Industrial Motors

2008 Lexus

Jansen et al., AIAA 2015-3890; Duffy, et al., AIAA 2015-3891

Minimumacceptableelectricdrivesystemperformance

Median

Electrical Machine ProjectionsTechnology Impact on Specific Power for Non-Superconducting Machines


Flight-Weight Power Management and Electronics

Lightweight power transmission

Distributed propulsion control and power systems architectures

Lightweight power electronics

Integrated motor with high power density power electronics

• Multi-KV, Multi-MW power system architecture for aircraft applications

• Power management, distribution and control at MW and subscale (kW) levels

• Integrated thermal management and motor control schemes

• Flightweight conductors, advanced magnetic materials, and insulators

• Collaborations with GE Global Research, Boeing, U of Illinois on flight-weight 1 MW inverters

Lightweight Cryocooler

Superconducting transmission line


NASA NRAs for 1MW Inverter Development

Key Performance

Metrics

Specific Power (kW/kg)

Specific Power (HP/lb)

Efficiency (%)

Minimum 12 7.3 98.0Goal 19 11.6 99.0

Stretch Target 25 15.2 99.5

Key PerformanceMetrics

Specific Power (kW/kg)

Specific Power (HP/lb)

Efficiency (%)

Minimum 17 10.4 99.1Goal 26 15.8 99.3

Stretch Target 35 21.3 99.4

Cryogenic Temperatures

Ambient Temperatures

• GE – Silicon Carbide TRL 4 in 2018• Univ. of Illinois – Gallium Nitride

• Boeing – Silicon CoolMOS, SiGeTRL 4 in 2019

Key element for generator rectification and motor drive control


Integrated System Testing and Validation

NASA-GRC PEGSSoftware/Hardware emulationhardware-in-the-loop electrical grid

NASA-AFRC Flight simulator – Flight Dynamics

NASA GRC - NEAT2MW Configurable Power Testbed

NASA-AFRC HEISTIronbird / Hardware in the Loop

• Validate components and power system benefits predictions

• Study component interactions to validate performance and matching at steady-state and transient operation

• Develop MW-level power system testing and modeling capability

• Demonstrate technology at appropriate scale for best research value

• Integrate power, controls, and thermal management into system testing to identify system-level issues early

• Develop and test flight control methodology for distributed propulsion


• Establish reference hybrid electric propulsion systems for component maturation

• Identify “tall pole” technologies

• Industry collaborations:

− Hybrid-electric geared turbofan concept (UTRC, P&W, UTC Aero Systems)− Hybrid-electric propulsion system concept (Rolls Royce, Boeing, GA Tech)

• Continuously evaluate reference designs

− Inform technology investment strategy− Establish guidelines for technology scalability to commercial transport class

Boeing“SugarVolt”N+3concept NASAN-3Xconcept

Conceptual Designs of Hybrid Electric Propulsion Systems


Conceptual Designs of Hybrid Electric Propulsion Systems

• Hybrid-electric geared turbofan (hGTF) conceptual design (UTRC, P&W, UTC Aerospace Systems)

• High efficiency drive gear integrating high speed motor and low pressure turbine

• Bi-directional flow of power

• Hybrid battery/fuel cell for energy storage

• Combined fuel/fan thermal management system

• Hybrid gas-electric propulsion system conceptual design (Rolls Royce, Boeing, GA Tech)

• Identify best performing architecture based on engine cycles, motor, power conversion, energy storage, and thermal management

• Innovative integration of novel gas turbine cycles and electrical drives

• Potential side effects of system design considerations

• Provide roadmap and tech maturation plan


STARC-ABL Turboelectric BLI Aircraft Concept

Welstead et al., Presented at AIAA SciTech, Jan. 2016

Configuration• 154PAXTubeandwing,M=0.7• 2downsized turbines:80%takeoff thrust,

55%cruisethrust• 1electricallypoweraftpropulsor: 20%

takeoffthrust,45%cruisethrust• 2x1.4MWGenerators,2.6MWMotor• ElectricMachinesassumeNASANRA

targetsfor efficiencyandspecificpower

KeyFeatures• Usesexistingairport infrastructure• SOABatteries• Configurationmeetsspeedandrange

requirementofbaselineaircraft• 7-12%fuel(andenergy)consumption

reductioncomparedtobaselineN+3aircraftfor900-3500nmmission


Concluding Remarks


The Path Forward…

• Focus on future single-aisle twin engine and large regional jets• Viable concepts with net reduction in energy use• Development of core technologies: turbine-coupled motors, generators,

power system architecture, power electronics, thermal management, flight controls

• Simulation and modeling tools for propulsion, vehicle, electrical, and flight control systems

• Technology demonstrations of components and architectures• Exciting times ahead


Documents

A NASA PERSPECTIVE ON ELECTRIC PROPULSION …machineroadmap.ece.illinois.edu/files/2016/04/Madavan.pdf · − Hybrid-electric propulsion system concept (Rolls Royce, Boeing, GA Tech)