MIT engineers built a one

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Engineers at the Massachusetts Institute of Technology (MIT) have successfully created a one-megawatt motor which is a crucial stepping stone in making large electric planes in the future. The team has tested individual components of the motor and computed to show that it can generate one megawatt of output, a press release said.

With the world focused on reducing its carbon emissions to "net zero" by 2050, aviation is a sector that needs maximum innovation to achieve this target. Large aircraft that haul passengers and cargo today also have large carbon footprints. However, solutions for the electrification of aviation are still small and incapable of replacing large jet engines.

Attempts at making fully electric planes are usually small. The motors used to propel them can only generate a few hundred kilowatts of power at a time. Large aircraft demand larger output from the motors, so MIT engineers set out to develop a one-megawatt electric motor.

To understand the difficulty in making a megawatt electric motor, one first needs to understand how an electric motor works. Conventionally, electric motors use electrical energy to generate a magnetic field - typically by sending current through copper coils.

A magnet placed near the coils spins in the direction of the magnetic field generated and drives a fan or a propeller with it. Larger copper coils must be used to generate more power from the motor. However, this also increases the heat generated during the process resulting in the addition of cooling elements to the setup.

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All these components add to the weight of the motor, making it more challenging to be used for aerial applications.

The MIT engineers designed motor consists of a high-speed rotor lined with magnets of varying polarity orientations and a compact low-loss stator that fits inside the rotor but is filled with an intricate array of copper windings on the inside. The team also made a distributed power electronics system using 30 custom-built circuit boards that precisely change currents through the copper windings at high frequencies.

The circuit boards are closely coupled with the machine to minimize transmission loss, and an integrated heat exchanger provides air cooling when the components are at work. For now, the researchers have tested these components individually and determined that the system design can generate one-megawatt output.

Later this year, the components will be assembled and begin testing the motor as a whole. The researchers are confident that the motor will be capable of powering a regional aircraft, and multiple motors could be along the wing in future aircraft design configurations.

The motor can be powered by a battery or a fuel cell or could be teamed up with jet engines to enable hybrid propulsion systems. "No matter what we use as an energy carrier — batteries, hydrogen, ammonia, or sustainable aviation fuel — independent of all that, megawatt-class motors will be a key enabler for greening aviation," said Zoltan Spakovszky, project lead at MIT, in a press release.