opportunities and challenges of electric aircraft propulsion · opportunities and challenges of...

Opportunities and Challenges of Electric Aircraft Propulsion Tagung Energiesysteme - Elektromobilität Dr.-Ing. Claus Müller - Brugg, 24.10.2017

siemens.com Unrestricted © Siemens AG 2017

© Siemens AG 2017 eAircraft

Siemens eAircraft flight test history

2011

Hybrid electric Diamond Aircraft eStar 1 and eStar 2

2013

Fully electric Pipistrel WattsUp trainer

2014

2016

Record motor SP260D in the Extra 330LE

2016

Fully electric Magnus eFusion


Battery system

Inverter

Auxiliary

system

Electric Motor with Bearing

Controller

Cooling

Magnus eFusion - fully electric aircraft propulsion system installed firewall-forward

Magnus eFusion – maiden flight Summer 2016

Propulsion System Data

Power 45 kW MCP

60 kW MTOP 85 kW max.

Nmax 2500 rpm

DC-link voltage (nominal) 350 VDC

(300 …450 V)

Torque MBoost 324 Nm

Battery 10.1 kWh

Max. airspeed 97 KIAS

Aircraft Data

Empty weight including batteries and parachute 410 kg

MTOW 600 kg

Wingspan 8.4 m

Length 6.6 m

Height 2.4 m


Flying testbed for ¼-MW class electric propulsion systems

Extra 330LE - maiden flight summer 2016

*

Source: flyer.co.uk

Propulsion System Data+

𝑃𝑃max 260 kW

𝑃𝑃cont 230 kW

𝑁𝑁cont 2250 rpm

𝑀𝑀cont 1000 Nm

𝜂𝜂Mot max. 95%

𝑚𝑚Mot, including propeller bearing 50 kg

Aircraft Data

MTOW 1000 kg

Wingspan 8.0 m

Height 2.6 m

Length 7.5 m

Wing area 10.7 m2

* As rated in the Extra 330LE


LiIo

n/Li

Po c

omm

erci

ally

ava

ilabl

e

MB-E1

Solair 1

Taurus G4

eGenius

E-FAN

E-FAN 1.0

EXTRA 330LE

Short History of Electric Aircraft Propulsion


On April 7th, 2016, Airbus Group and Siemens AG have Signed a Long-Term Collaboration Agreement in the Field of Hybrid Electric Propulsion Systems

“We believe that by 2030 passenger aircraft below 100 seats could be propelled by hybrid propulsion systems...”

Airbus Group CEO Tom Enders

“Siemens is determined to establish hybrid-electric propulsion systems for aircraft as a future business.”

• Both companies take a significant joint development decision

• Demonstrate the technical feasibility of various hybrid-electric propulsion systems by 2020

• Assemble joint development team of some 200 employees

• Prototype propulsion systems ranging from a few 100 kW up to 10 MW and more

• for short, local trips with aircraft below 100 seats, helicopters or UAVs up to classic short and medium-range journeys.

• Target: breakthrough innovation in aerospace e-mobility


Outlook for electric propulsion market

Today 2050

Experimental flight with small aircraft demonstrated

Today

Market ramp-up for certified systems, e.g., two- and four-seaters

2022

Airlines offering scheduled flights based on hybrid-driven aircraft

2030 E-propulsion is the standard solution for all aircraft segments

2050

Fully electric flying for medium range (energy storage capacity sufficient)

2025

Market entry for ultra-light and military due to less strict certification rules

2018

Increasing dominance of electric propulsion

Source: eAircraft market evaluation

We expect electric propulsion to be the standard solution by 2050


Opportunities

1. Operating Cost Reduction

Reduced Fuel Consumption 2. Higher Market Acceptance

(reduced Noise- und CO2-Emissions)

3. New Airframe and Traffic Concepts Service, Insurance,

etc.

Crew

15% 14% 100%

TCO Fuel

20%

Invest

51%

Total cost of ownership (ex.: Boeing 737-800))1

Fuel is a Cost Driver

1) Source: eAircraft market evaluation


Source: fra-spotterforum.de

Source: Airbus / Aero

Turbofan Propulsive Efficiency • Is a function of bypass ratio (BPR) • High BPR lead to large fan diameters

• Large fans require higher landing gear

1970‘s: 737-100 BPR=1

2016: A320neo BPR=12

Aircraft Propulsive Efficiency


Distributed Propulsion • Larger total disc area (BPR) • Reduced tip speed

• Thrust vectoring

• Redundancy

Electric Propulsion is favorable for distributed propulsion

• Excellent scalability

• Very small nacelle diameter possible



Free Stream Propulsion • Propeller-wing-integration can increase

lift du to increased kinetic stream energy

• Smaller nacelles for propulsion help to reduce total drag.

Source: Diamond Aircraft Industries



Source: Bauhaus Luftfahrt

Boundary Layer Ingestion • Providing a fan at the aft of the

fuselage, the wake field can be compensated

• Significant reduction in fuel consumption possible

• Electric drives are favored for this application



Opportunities




3. New Airframe and Traffic Concepts

Target Emissions can only be achieved by use of disruptive technology.

2050 2040 2030 2020 2010

“Flightpath 2050” EU Vision envisages a 75% reduction of CO2 emissions per passenger mile

Enhancements of current technologies

Biofuels und disruptive concepts (e.g. eAircraft) CO

2 E

mis

sion

s

Jahr

1) IATA technology roadmap, June 2013


Opportunities




3. New Airframe and Traffic Concepts

Distributed Electric Propulsion will enable new aircraft concepts

1) www.nasa.gov/centers/armstrong/Features/leaptech.html (Dezember 2015) 2) http://aviationweek.com/technology/quality-crowd-designed-uavs-surprises-airbus (July 2015) 3) www.jobyaviation.com (Dezember 2015) 4) www.nasa.gov/langley/ten-engine-electric-plane (Dezember 2015)

1) 2)

3) 4)


Source: Airbus Group

Source: Airbus Group Source: Lilium Aviation

Source: Terrafugia

Visions of future individual mobility in the air


New markets enabled by electric aircraft propulsion

Uber vision: elevate • Passenger transport in urban areas • Aerial service on demand

Source: https://www.uber.com/elevate.pdf


Challenges

1. Power Density 2. Safety

3. Environmental Conditions


Electric Motor Power Density

• Industrial induction motors 0.2 – 0.4 kW/kg

• Forced ventilated traction motors 0.6 – 1.0 kW/kg

• Liquid cooled automotive traction 1.0 – 2.5 kW/kg

• 2016 Siemens eAircraft SP260 5.2 kW/kg

• 2025 Electric aircraft propulsion > 10 kW/kg

Evolution in power density of electric motors

𝑃𝑃𝑀𝑀𝑀𝑀𝑀𝑀 ≈ 1/2 MW

𝑃𝑃𝑀𝑀𝑀𝑀𝑀𝑀/𝑚𝑚𝑀𝑀𝑀𝑀𝑀𝑀 = 0,87 kW/kg

𝑃𝑃𝑀𝑀𝑀𝑀𝑀𝑀 ≈ 1/4 MW

𝑃𝑃𝑀𝑀𝑀𝑀𝑀𝑀/𝑚𝑚𝑀𝑀𝑀𝑀𝑀𝑀 = 5,2 kW/kg


Pcont = 261 kW nmax = 2500 rpm Mcont = 1000 Nm η260kW = 95 % D = 416 mm L = 300 mm P/M ~ 5.2 kW/kg

Motor Data

Motor sizing and loading • Optimization levers:

• Current loading • High-end materials • Motor topology

𝑷𝑷𝒎𝒎 = 𝒏𝒏 ∗ 𝒍𝒍𝒆𝒆 ∗ 𝒅𝒅𝒔𝒔𝒔𝒔𝟐𝟐 ∗ 𝝅𝝅𝟐𝟐

√𝟐𝟐∗ 𝒌𝒌𝒘𝒘𝒍𝒍 ∗ 𝑨𝑨 ∗ 𝑩𝑩𝜹𝜹𝒔𝒔�� ∗ 𝒄𝒄𝒄𝒄𝒔𝒔𝝋𝝋𝒔𝒔

Mechanical Power

Rotational Speed

Active Length

Bore Diameter

Winding Factor

Current Loading

Air-gapflux density sine wave amplitude

Internal Power Factor

Esson’s number C

Motor Weight Optimization


Extended eAircraft portfolio

Total component weight and efficiency

Core eAircraft portfolio

AC DC DC AC

DC DC

Storage

Power Distribution Motor1) Generator1)

Turbine / ICE

Propulsion System

Propulsion Unit • Motor • Inverter • Propeller • Gearbox

Power Generation • Generator • Inverter • Controller • Turbine/ICE3)

Power Distribution • Circuit Breaker • Switches • Cables • Connectors

Energy Storage • Battery Packs • Converter • BMS2)

1) E-machines are capable to fulfill “power generation” and/or “propulsion” depending on e.g. mission profile, requirements and/or mode of operation, 2) Battery Management System (BMS), 3) Internal Combustion Engine (ICE)

96% 98% 99% 98% 96% η=87,6%


Challenges




Target Failure Rates better than λ=10E-6 • Propulsion must be fault operational • Failure-oriented design • Short-circuit current <= Nominal current • Single Lane architecture not sufficient • Multiple lanes to reduce excess power

Source: Bennet: Fault Tolerant Electromechanical Actuators for Aircraft

Lowest Failure Rates


Safety oriented Development Standards

Railway EN 50126 (RAMS) EN 50128 (SW) EN 50129 (System, Assessment) EN 50159 (Communication)

Automotive ISO 26262 (System, SW, HW)

Aviation SAE ARP 4761 (Safety Assessment) SAE ARP 4754 A (Devel. Process) ED12C DO-178C (SW) ED80 DO-254 (HW)

International Safety Standard IEC61508 (System, SW, HW)

Nuclear IEC61513 IEC60880 (SW) (System, SW, HW)

Process Industry IEC61511

Medicine IEC60601

Machinery IEC62061

Military Def Stan 00-56, …

Courtesy clip art


Challenges




Low Pressure, Low Temperatures at 40.000 ft. altitude • Temperature: -56°C

• Qualified electric components

• Air pressure: ~200mbar

Source: geogrify.net

Environmental Conditions


Low Pressure, Paschen law • 1cm gap – breakdown voltage

• 30kV DC @ sea level • 1.2kV @ 47000ft • 327V @ 150000ft

• Precaution has been taken regarding

• Tracking • Partial Discharging • Arcing

• Large creepage and clearance distances • Special insulation

Source: MOOG aircraft group

Environmental Conditions


Single Event Effects (SEE) • Single-Event-Burnouts (SEB)

typical destructive phenomenon of cosmic radiation

• Particle rate at flight altitude is ~300 times compared to ground level.

• Particle cocktail is different to ground level

• Measure: Severe voltage derating to match cut-off-voltage

Source: astronomy.nmsu.edu

Source: ABB Application Note 5SYA 2042-06

Power Electronics Challenges – Cosmic Radiation


Thank you for your attention

Dr.-Ing. Claus Müller

Head of CoC Aircraft Drives and Controls

eAircraft

Siemens Corporate Technology

CT N47P AIR AS ADC

E-mail: [email protected]

Internet siemens.com/corporate-technology

mailto:[email protected]

http://siemens.com/corporate-technology



opportunities and challenges of electric aircraft propulsion · opportunities and challenges of...

Documents