The NASA Electric Aircraft Testbed (NEAT) is a

NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding t ...

reconfigurable

testbed A testbed (also spelled test bed) is a platform for conducting rigorous, transparent, and replicable testing of scientific theories, computational tools, and new technologies. The term is used across many disciplines to describe experimental rese ...

Plum Brook Station NASA John H. Glenn Research Center at Lewis Field is a NASA center within the cities of Brook Park and Cleveland between Cleveland Hopkins International Airport and the Rocky River Reservation of Cleveland Metroparks, with a subsidiary facilit ...

, Ohio, used to design, develop, assemble and test

electric aircraft An electric aircraft is an aircraft powered by electricity. Electric aircraft are seen as a way to reduce the environmental effects of aviation, providing zero emissions and quieter flights. Electricity may be supplied by a variety of methods, ...

power systems, from a small, one or two person aircraft up to

airliner An airliner is a type of aircraft for transporting passengers and air cargo. Such aircraft are most often operated by airlines. Although the definition of an airliner can vary from country to country, an airliner is typically defined as an ...

research agreements (NRA) are granted to develop electric-propulsion components. They will be completed in 2019 and the internal NASA work by 2020, then they will be assembled in a megawatt-scale drive system to be tested in the

narrowbody A narrow-body aircraft or single-aisle aircraft is an airliner arranged along a single aisle, permitting up to 6-abreast seating in a cabin less than in width. In contrast, a wide-body aircraft is a larger airliner usually configured with mult ...

-sized NEAT.

Machines

The

University of Illinois The University of Illinois Urbana-Champaign (U of I, Illinois, University of Illinois, or UIUC) is a public land-grant research university in Illinois in the twin cities of Champaign and Urbana. It is the flagship institution of the University ...

is developing a 1-megawatt

permanent magnet synchronous motor A synchronous electric motor is an AC electric motor in which, at steady state, the rotation of the shaft is synchronized with the frequency of the supply current; the rotation period is exactly equal to an integral number of AC cycles. Sync ...

spinning at 18,000 rpm to drive a Rolls-Royce LibertyWorks' Electrically Variable Engine turbofan from a battery for taxiing, takeoff and idle descent in a

parallel hybrid Hybrid vehicle drivetrains transmit power to the driving wheels for hybrid vehicles. A hybrid vehicle has multiple forms of motive power. Hybrids come in many configurations. For example, a hybrid may receive its energy by burning gasoline, but sw ...

Ohio State University The Ohio State University, commonly called Ohio State or OSU, is a public land-grant research university in Columbus, Ohio. A member of the University System of Ohio, it has been ranked by major institutional rankings among the best publ ...

is building 300-kW and 1-megawatt prototype motors, a 2,700 rpm, 1-m (3.3-ft) diameter, 2.7-megawatt

liquid cooled Liquid cooling refers to cooling by means of the convection or circulation of a liquid. Examples of liquid cooling technologies include: * Cooling by convection or circulation of coolant, including water cooling * Liquid cooling and ventilatio ...

ring

induction motor An induction motor or asynchronous motor is an AC electric motor in which the electric current in the rotor needed to produce torque is obtained by electromagnetic induction from the magnetic field of the stator winding. An induction mot ...

and designed a 5,000 rpm, 10-megawatt turbofan integrated ring motor. These

electric machine In electrical engineering, electric machine is a general term for machines using electromagnetic forces, such as electric motors, electric generators, and others. They are electromechanical energy converters: an electric motor converts electricity ...

s target 13 kW/kg and over 93% efficiency, while NASA

Glenn Research Center NASA John H. Glenn Research Center at Lewis Field is a NASA center within the cities of Brook Park and Cleveland between Cleveland Hopkins International Airport and the Rocky River Reservation of Cleveland Metroparks, with a subsidiary facilit ...

is developing a

superconducting electric machine Superconducting electric machines are electromechanical systems that rely on the use of one or more superconducting elements. Since superconductors have no DC resistance, they typically have greater efficiency. The most important parameter th ...

with a 16 kW/kg goal and above 98% efficiency: a 0.4-m-dia, 6,800 rpm, 1.4-megawatt wound-field

synchronous motor A synchronous electric motor is an AC electric motor in which, at steady state, the rotation of the shaft is synchronized with the frequency of the supply current; the rotation period is exactly equal to an integral number of AC cycles. Sync ...

using a self-cooled,

high-temperature superconducting High-temperature superconductors (abbreviated high-c or HTS) are defined as materials that behave as superconductors at temperatures above , the boiling point of liquid nitrogen. The adjective "high temperature" is only in respect to previ ...

rotor winding.

Voltage

The highest voltage used now is 540 (±270) volts, but distributing megawatt-scale power will require higher

voltage Voltage, also known as electric pressure, electric tension, or (electric) potential difference, is the difference in electric potential between two points. In a static electric field, it corresponds to the work needed per unit of charge to m ...

to reduce

current Currents, Current or The Current may refer to: Science and technology * Current (fluid), the flow of a liquid or a gas ** Air current, a flow of air ** Ocean current, a current in the ocean *** Rip current, a kind of water current ** Current (stre ...

for smaller, lighter

electric cable An electrical cable is an assembly of one or more wires running side by side or bundled, which is used to carry electric current. One or more electrical cables and their corresponding connectors may be formed into a ''cable assembly'', whic ...

s. One megawatt over need 900 kg at 540 V but would be reduced to 200 kg at 2,000 V DC. A near-term hybrid would need 1,000–3,000-volt and a fully turboelectric large aircraft 5,000–10,000-volt, like ship power systems but

arcing An electric arc, or arc discharge, is an electrical breakdown of a gas that produces a prolonged electrical discharge. The electric current, current through a normally Electrical conductance, nonconductive medium such as air produces a plasma (p ...

occurs at much lower voltages at low pressures than at sea level.

Inverters

While a

battery Battery most often refers to: * Electric battery, a device that provides electrical power * Battery (crime), a crime involving unlawful physical contact Battery may also refer to: Energy source *Automotive battery, a device to provide power t ...

power source would use a

direct current Direct current (DC) is one-directional flow of electric charge. An electrochemical cell is a prime example of DC power. Direct current may flow through a conductor such as a wire, but can also flow through semiconductors, insulators, or even ...

distribution, a

gas turbine A gas turbine, also called a combustion turbine, is a type of continuous flow internal combustion engine. The main parts common to all gas turbine engines form the power-producing part (known as the gas generator or core) and are, in the directi ...

power source would also allow

alternating current Alternating current (AC) is an electric current which periodically reverses direction and changes its magnitude continuously with time in contrast to direct current (DC) which flows only in one direction. Alternating current is the form in whic ...

which would need

power converter Power most often refers to: * Power (physics), meaning "rate of doing work" ** Engine power, the power put out by an engine ** Electric power * Power (social and political), the ability to influence people or events ** Abusive power Power may a ...

s, mainly

inverter A power inverter, inverter or invertor is a power electronic device or circuitry that changes direct current (DC) to alternating current (AC). The resulting AC frequency obtained depends on the particular device employed. Inverters do the opp ...

s to convert DC to controlled, variable-frequency AC to regulate a motor speed and torque.

Silicon carbide Silicon carbide (SiC), also known as carborundum (), is a hard chemical compound containing silicon and carbon. A semiconductor, it occurs in nature as the extremely rare mineral moissanite, but has been mass-produced as a powder and crystal sin ...

iCand

gallium nitride Gallium nitride () is a binary III/ V direct bandgap semiconductor commonly used in blue light-emitting diodes since the 1990s. The compound is a very hard material that has a Wurtzite crystal structure. Its wide band gap of 3.4 eV affords it ...

aNswitches can operate at higher frequencies with lower losses, increasing efficiency. GE is building a 2,400-volt DC, 1-megawatt inverter with SiC switches and its 1.7-kW

MOSFET The metal–oxide–semiconductor field-effect transistor (MOSFET, MOS-FET, or MOS FET) is a type of field-effect transistor (FET), most commonly fabricated by the controlled oxidation of silicon. It has an insulated gate, the voltage of which d ...

s power modules. The University of Illinois is building a 1,000 volts DC, 200-kW "flying capacitor" scalable to a 1-megawatt with GaN-based

field-effect transistor The field-effect transistor (FET) is a type of transistor that uses an electric field to control the flow of current in a semiconductor. FETs (JFETs or MOSFETs) are devices with three terminals: ''source'', ''gate'', and ''drain''. FETs contro ...

switches. Both are liquid cooled and target 19 kW/kg at 99% efficiency, but

Boeing The Boeing Company () is an American multinational corporation that designs, manufactures, and sells airplanes, rotorcraft, rockets, satellites, telecommunications equipment, and missiles worldwide. The company also provides leasing and product ...

is developing a cryogenically cooled 1-megawatt inverter for 26 kW/kg and 99.3% efficiency with

off-the-shelf Off-the-shelf may refer to: * Commercial off-the-shelf, a phrase in computing and industrial supply terminology * Government off-the-shelf * Ready-to-wear * Shelf corporation, a type of company * Off the Shelf Festival, a festival of writing and r ...

silicon semiconductors, and is currently fabricating a liquid-nitrogen-cooled 200-kW inverter before a 1-megawatt one.

References

{{reflist Glenn Research Center Science and technology in Ohio