HISTORY OF PERMANENT MAGNET MOTORS
The electric vehicle industry has been built on these motors
Permanent magnet machines have been the traction motor of choice for OEMs since the first modern electrified vehicles hit the roads in the late 1990s. At that time, engineers favoured the permanent magnet motor for its efficiency, relative power density and simplicity, and since then an entire electric vehicle industry has grown up around these machines.
The engineers working on those early hybrid vehicles couldn’t have foreseen the issues that mass production of EVs containing permanent magnet motors could cause. Nor could they predict our insatiable need for personal electronics and the pressures these two trends would place on rare earth metal production or levels of electronic waste.
Permanent magnet motors are environmentally and financially unsustainable
But now we do know the realities of mass-producing permanent magnet traction motors for a burgeoning electric vehicle industry. For each permanent magnet traction motor produced, around 2kg of rare earth material is needed, costing around $200 – although that price is incredibly volatile (it increased 240% in the year up to March 2021).
That means that the production of each traction motor can create around 3kg of radioactive waste and up to 56kg of CO2. Those worrisome figures only become worse when you consider that some forecasts suggest we’ll be producing 128 million EVs per year within the next 20 years. Shockingly, if rare earth metal production keeps pace with this growth, it could be producing enough acidic sewage to fill an additional 21,000 Olympic-sized swimming pools every year.
So far attempts to remove magnets has meant a compromise on performance and range
So, it’s clear that a different, magnet-free solution is needed for EV traction motors, and fast. But there’s a good reason permanent magnet machines have been favoured over other existing motor technologies so far.
True, some vehicle manufacturers have incorporated induction motors into their electric cars instead, but the result of using this less power-dense solution has meant heavier vehicles and less predictable real-world range.
A new motor technology that is more sustainable, more efficient and higher performing
That’s where AEM’s technology comes in. A semi-sinusoidal machine, AEM’s technology changes how electricity is fed into the coil and swaps the permanent magnets in the rotor for electrical steel.
The result is a motor that is not only more sustainable to produce and dispose of than the permanent magnet machine, it is also more efficient and power dense, while even providing significant safety benefits.
So you see, there really is an alternative to the permanent magnet motor that not only provides performance advantages, but stops us from falling into yet another environmental trap for future generations.