Drives & Controls Magazine September 2023

n MOTORS achieve comparable power to similarly sized PM motors containing rare-earths. A challenge is to contain the magnets effectively in the rotor. One potential answer would be to wrap the motor in carbon fibre – a technology that Tesla has already demonstrated in its Plaid vehicles. Another challenge is that, for optimal operation, the ferrite magnets would need to be heated. This is the opposite issue to that faced by neodymium magnets, but is not unachievable. It should be noted that Ultimate Transmissions’ design is still at the simulation stage. Tesla could take a different approach, such as using its own alternative magnetic materials. But in simulations, the Australian approach has shown similar power, reduced costs and a reduced weight at the penalty of slightly reduced torque and a longer motor stack. There is an increasing focus, especially outside of China, on reducing the rare-earth content of electric motors. There are several strategies, each with its own trade-offs and opportunities for motor manufacturers and material suppliers. It seems likely that rareearth PM motors will remain the most common technology, largely as a result of China’s dominance in the EV market, and rareearth mines starting to come online in other parts of the world. Tesla alone dropping its need for rare-earths could affect global demand for the materials, but if other car-makers adopt similar strategies, this could result a substantial shift to more sustainable and less price-sensitive alternatives to rare-earth magnets. We believe that that by 2034 rare-earth-free motors, such as those mentioned above, will account for nearly 30% of the global EV market. n This article is based on IDTechEx's "Electric Motors for Electric Vehicles 2024-2034" report which analyses various motor technologies for performance, market adoption and future potential. Mahle’s “technology kit” combines the advantages of two types of motor: a continuous-torque machine; and a magnet-free and rare-earth-free contactless design Direct