n TECHNOLOGY A JAPANESE JOINT VENTURE between Hitachi, Honda and JIC Capital, has developed an electric motor for electric vehicles based on a rare-earth-free synchronous reluctance (SynRM) technology. The JV, called Astemo, aims to have the first practical applications of the motor by around 2030 and says that it would represent the world’s first use of SynRM motors in mass-produced vehicles. The motor generates rotational forces by inducing magnetism in an iron-core rotor. Rare-earth-free magnets incorporated into a main drive motor are used to deliver a high output. This enables the replacement of conventional permanent magnet motors in BEV (battery EV) drive systems, which normally need large amounts of rare-earth materials. The main motor, designed to generate a continuous driving force, achieves an output of 180kW. An auxiliary 135kW motor used for power-assist duties, eliminates energy losses during coasting, developing a combined output of 315kW. Most EV motors rely on permanent magnets in the rotor that incorporate rare-earth elements such as neodymium to generate strong magnetic fields. But these materials entail significant geopolitical risks, and ensuring a stable supply can be a challenge. Rare-earth-free ferrite magnets, while readily available, have a magnetic force that is only one-third or less of those using rare-earths. This means a motor needs to be three times the size to deliver the same output. In response, induction motors and wound-field motors have been developed that avoid the need for permanent magnets. However, these need significant amounts of copper on the rotor, representing a possible resource risk. Astemo has developed its synchronous reluctance motor as an alternative. It generates a rotational force by using differences in magnetic resistance (reluctance) based on the shape of the rotor core. A “multi-layer flux” structure divides the magnetic force transmission path into multiple layers. The current is controlled precisely to form magnetic poles in the rotor core, and to compensate for the powerful magnetic forces generated by neodymium magnets. Creating magnetic poles in the rotor core requires large currents to flow through the stator coils, posing the risk of the coils overheating. Astemo says it has been able to suppress heat generation in the motor by developing a structure that immerses the slots and ends containing the coils in cooling oil. For the main drive motor, which runs continuously, a magnet-assisted synchronous reluctance design, incorporating ferrite magnets, achieves an output of 180kW, while limiting the size increase to 30%, compared to conventional rare-earth permanent magnet motors. For the auxiliary drive motor, Astemo has developed a synchronous reluctance motor that needs no magnets at all. If magnets were embedded in the auxiliary drive, they could act as a braking force when the main drive rotor is coasting, resulting in energy losses. The auxiliary drive therefore operates only when needed to deliver power assistance of up to 135kW. This limits the power consumption of the entire BEV drive system. The new rare-earth-free motor is said to deliver a similar performance to a conventional BEV motor. It reduces the procurement risks and price volatility associated with rare-earths, enabling supply of the motors to remain stable. Furthermore, reducing energy losses across the entire BEV drive system – including both main and auxiliary drives – will curb power consumption over a wide range of driving scenarios. Astemo, headquartered in Tokyo, employs around 80,000 people, and has operations in the Americas, Asia, China, Europe and Japan. www.astemo.com/en Rare-earth-free synchronous reluctance motors for EVs could be the world’s first Neural networks halve distance measurement errors February 2026 www.drivesncontrols.com 20 LEUZE CLAIMS THAT it has been able to cut measurement errors in industrial applications by using neural networks. The technique improves accuracy without needing extra computing resources. Optical distance sensors using time-of-flight (TOF) technology offer many benefits. They allow fast, contactless measurement of long distances, are insensitive to ambient light, and provide continuous distance data in real time. They work by recording the time it takes for light – usually in the form of laser or LED pulses – to travel to an object and back. But TOF technology has its limitations. Its accuracy depends on the object surface. Dark surfaces can weaken the reflected signal, resulting in narrower pulses and delayed echo detection. Bright surfaces, on the other hand, generate stronger signals with a wider pulse width, that are detected earlier. That means that the returning signal is detected at different times depending on whether the object surface is light or dark, resulting in measurement errors. Until now, mathematical models based on algorithms have been used to correct these errors. Because the model parameters are fixed, the functions cannot adapt to changing conditions. Leuze says it now has a much more precise and flexible approach. Instead of working with rigid formulae, it is using neural networks to determine the correction value. Astemo’s main drive stator and rotor
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