Vitesco Technologies announced that it will showcase a separately excited synchronous electric motor this month at the International Electric Vehicle Symposium.

A separately excited synchronous motor (SSM) is a motor using windings in the rotor, with a function similar to the permanent magnets in a permanent magnet synchronous motor (PMSM). This allows the motor maker to circumvent the use of rare earth permanent magnet motors, which have captured the market share in electric vehicles (EVs) because of their higher efficiency across a wider speed range.

A key reason to look for alternatives to rare earth PMSMs is the supply risk of rare earth raw materials. China is by far the largest miner of rare earth as well as the largest importer of additional feedstock to service its domestic rare earth supply chain. This has allowed China to extend its dominance along the value chain and account for over 95% of global neodymium-iron-boron (NdFeB) magnet production – the magnet that is powering the EV revolution.

Some OEMs, like BWM, have opted for non-permanent magnet motor technologies to avoid the supply risk of NdFeB magnets, although smaller NdFeB magnets are still used in various other parts of the vehicle. Choosing NdFeB magnets comes with improved efficiency, miniaturisation (light-weighting) and optimisation, which translates in the drivetrain to a higher range for a given battery capacity. Or relating that to costs, the ability to reduce the battery pack size and raw material requirement while maintaining the vehicle’s range.

Vitesco’s SSM motor is designed to be optimised for long-distance driving at higher speeds. According to a study by the Bureau of Transport Statistics, over half of long-distance trips are taken for recreation, with only 13% representing commuting and personal business. When it comes to mass market commuter travel, stop-start low-speed driving will likely be the main use of the drivetrain of most EVs, for which PMSM and NdFeB technologies will continue to offer upside in performance and drivetrain optimisation. Nevertheless, with supply risks ramping up for rare earths, substitution is forecast to play an important role in the industry.