NASA Electric Aircraft Testbed Single-Aisle Transport Air Vehicle Hybrid

Electric Tail-Cone Thruster Powertrain Configuration and Test Results

July 12, 2018

Dr. Rodger DysonHybrid Gas Electric Propulsion Technical Lead

NASA Glenn Research Center

https://ntrs.nasa.gov/search.jsp?R=20180006123 2020-04-30T03:42:05+00:00Z

Reconfigurable Powertrain Testbed

• Located at NASA Glenn Plum Brook Station in the recently refurbished Hypersonic Tunnel Facility (HTF)

• Full-scale powertrain testing under actual flight scenarios

• Can support cryogenic fuel, high voltage, large wingspan, electromagnetic interference, and high power research h/ware

Planned Testing at NEAT• Phased approach with ~1 aircraft configuration per year (goal)

• Initially COTS, ambient

What is NASA Electric Aircraft Testbed (NEAT)?

• TRL maturation of:

– High voltage bus architecture –

Insulation, geometry, 600V up to 4500V

– High power MW Inverters, Rectifiers-

Commercial, In-House, NRAs

– High power MW Motors, Generators-

Commercial, In-house, NRAs

– System Communication –

Aircraft CAN, Ethernet, Fiber-optics

– System EMI Mitigation and Standards –

Shielding, DOD-160, MIL-STD-461

– System Fault Protection –

Fuse, Circuit Breaker, Current Limiter

– System Thermal Management –

Active/Passive, Ambient/Cryo, Distributed/Mixed

3Your Title Here

NASA Electric Aircraft Testbed (NEAT)

NASA Electric Aircraft Testbed (NEAT)

• Reconfigurable testbed to support full-scale large aircraft

powertrain testing

• Plans to demonstrate high fidelity turbo-generation and ducted

fan transient emulation and to test MW-class research motors,

inverters, and powertrains

National Aeronautics and Space Administration

www.nasa.gov 5

13 MW

Turbine

Engine

1.4 MW

Generator

3 φ ACRectifier

DC

Circuit

Protection

Devices

13 MW

Turbine

Engine

1.4 MW

Generator

Rectifier

Inverter

Or

Rectifier

3 φ AC DC

Motor

2.6MWFan

3 φ ACDC

Fuel

Fuel

Thrust and Power

Rectifier 2

Generator 2

Rectifier 1

Generator 1

Fan

Motor

Inverter

Cables

BLI Thrust

STARC-ABL Configuration

STARC-ABL Motor Pairing

Utilize Speed & Torque Maps under Takeoff, Landing, and Cruise Conditions

700V 270kW

motor/inverter

1MW 250KW 250KW 250KW 250KW

480

Vac

3-P

h

750KW 4160Vac/480VacTransformer

290K

W

480Vac-700Vdc

700Vdc

Four Parker 250KW Motors& Four Rinehart Inverters

MW-Scale Motor/Inverter Pair Powertrain Altitude Test Configuration

motor/inverter

1MW250KW 250KW 250KW 250KW

700Vdc

Four Parker 250KW Motors& Four Rinehart Inverters

Gearbox21000 RPM7000 RPM

Gearbox21000 RPM7000 RPM

-1200VDC

+1200VDC

700Vdc Regeneration0.86MW

Effic 0.98 Effic 0.98 Effic 0.945Effic 0.945

Altitude Chamber

Sea Level Sealed Chamber

Arbin Bi-directionalLufkinLufkin

Bulkhead

Flexible MW-Scale Aircraft Powertrain Altitude Testing

STARC-ABL Communication and Control

Response, Bandwidth, Shielding, Standards, and Topology

STARC-ABL Error Handling

Local hardware control Global software control

MonitorT, V, I, RPM, signal,

timeouts, and gradients

M1

M2

1MW7,000 RPM.

OUTPUT/INPUT

1MW21,000 RPM

INPUT/OUTPUT

10”

10”

2ӯ

3.5ӯ

1MW GEARBOX3:1 RATIOSF=2.61

10”

.25MW .25MW.25MW .25MW

M2 M2 M2M2

LovejoyDisc coupling

Kop-Flex 103Disc coupling

Kop-Flex 153Disc coupling

10”

motor/inverterFour Parker 250KW Motors& Four Rinehart Inverters

MW Research Motor Gearbox Connection to Facility Motors

Interfacing facility speed and voltage with aircraft research bus voltage and machine speed

11

Commencement of Testing for 500 kW STARC-ABL

“Aft ThrusterIn Altitude Chamber”

500 kW STARC-ABL Configuration

Inside Altitude Chamber

Single-String and STARC-ABL Powertrain Configurations

125kW Single-String

Full-scale Boeing 737-800 Powertrain Layout for EMI, thermal, impedance, latency, conformity, and reflections

Mach

12

NPSS

Motor 6

speed

altitude

Mach

throttle

Motor 2

torque/voltage

torque

Motor 3 Motor 4 Motor 7 Motor 8

NPSS

speed

altitude

Σ

torque torque

torque

torque

NPSS

Motor 5

speed

altitude

Mach

throttle

Motor 1

torque/voltage

torque

Wing Turbogenerators Tail Fan

input from PC

mechanical shaft

torque

torque

NEAT NPSS Control Strategy

First Single-String Test

Current 500 kW STARC-ABL System Interconnections

• 700V capable system• Separate PLC and DAQ• Fiber Optic Control• Isolated DC bus• Grounded structure and

shielding through glands• All COTS

Cooling Water SystemMW-scale Testbed

Flexible Dual-Shaft Motor Integration for MW-Scale

• Multiple 250kW machines on single shaft

• For cost-saving and reconfigurability

Torque Motor Speed Motor

Inverter

Speed Motor Speed Motor

500 kW Motor and Ducted Fan Emulation

InverterExposed Double Shaft

Provide actual dynamic altitude conditions up to 50,000 feet while also providing actual loading via NPSS real-time emulated ducted fan

Instrumentation Challenges and Implementation

Shielding requirements

constrain locations

Dynamic Power System Model

• NPSS – S-Code – Matlab/Simulink/Simpowersystems Powertrain Model• Scaled torque and inertia terms for dynamic similitude• T-MATS compatibility• High-speed Dewesoft DAQ for validation

Flight Profile for NPSS Testing

• Representative profile to compare NPSS controls at NEAT• Note delay in power required to power extracted due to communication delays

Generator M1 Model Validation

Very good agreement between predicted model data and hardware results

Motor M3 Model Validation

Very good agreement between predicted model data and hardware results

Full STARC-ABL Flight Profile – 900 NM

CHALLENGE MITIGATION

Thermally managing the motors Changing the coil configuration

Addressing EMI between the controls and inverter Insuring good shielding contact end-to-end

Load balancing the system High-speed DAQ

Communication delays Fiber optics and ARINC 664 Protocol

Bus transients and power quality improvement Smart energy storage

Fault management with a complex system Federated detection and control at inverters

Current 500 kW STARC-ABL System Grounding

Building grounding loop has effective 500 milliohm resistance.Aircraft standard is closer to 2 milliohm so will modify in the future.

Fault Management

Maintain bus voltage limits with braking resistors and one-way diode power supplies

DC Insulation Resistance Monitoring

AC Ground Fault

Detection

Structure and EMI Shield

Grounded

NEAT Vacuum System Design 24

Flight Altitude Powertrain Component Capability

• EMI shielding is critical for safe and proper operation of the powertrain even with DO-160G compatible equipment

• Federated fault response with localized feedback/controls are important for orderly shutdown sequencing

• Electric machines can be scaled and controlled to simulate a turbine and ducted fan operation

• System interactions between components must be tested to account for common modes, grounding loops, electrical and mechanical resonant conditions

• Spline coupling selection impacts controllability

• Turbine and Electric Powertrain modeling can be very accurate if the component controls are fully characterized

• Optical fiber and digital instrumentation are required for robust communication and sensors

• Higher voltage and current present new issues such as insulation resistance breakdown and power quality challenges when operating near rated equipment limits

• Torque measurements are effected by cogging, EMI, torsional resonance, spline back-lash, and acquisition rates

• Shielding throughout the powertrain limits the ability to acquire data from transducers forcing calculated results via inverter software measurements.

Lessons Learned

Next Steps

• Smart energy storage and fault management• Triple redundancy• Aircraft Grounding Scheme• Dual-Spool Power Extraction• Real-time turbine and ducted fan emulation• Altitude• Flight-Weight Components

Increasing Flight-Readiness

Summary

• Flexible Electric Aircraft Testbed Completed First STARC-ABL Flight Profile• Full-scale Single-Aisle Electric Aircraft Powertrain • Continue to add to capabilities (power, voltage, cooling, altitude)

• Up to 24-48MW with regeneration• 50,000 feet altitude in 15 minutes• >1MW thermal management• Full-size and safe with remote control

Powertrains• Goal is to evaluate multiple aircraft

configurations• Partnerships, collaborations

Components & Integrated Testing• Altitude, high voltage• Cryogenic, thermal• NASA-sponsored machines and power

electronics• Partnered testing in academia, gov’t,

industry

Altitude

Hosting HTF and nearby facilities make jet fueled power a possibility

MW Cooling

RemoteControl Building