The Japanese motion engineering company, Yaskawa, has developed an electric vehicle [EV] motor with a ferrite magnet core, avoiding rare-earth metals like neodymium, samarium, and yttrium.
The prices of rare-earth materials including neodymium, sharply fluctuate because many of them are eccentrically located, making it difficult to stably obtain them. Therefore, Yaskawa decided to develop an EV motor using a ferrite magnet, which has a lower price.
The company ensured a performance and dimensions equivalent to those of a motor using neodymium by optimizing the shapes and positions of magnet, motor core, etc.
Yaskawa made a change to the coil wiring itself: instead of using the standard round-cross-section wiring, Yaskawa switched to a rectangular-cross-sectioned wire, which stacks better on the rotor and stator. This resulted in a 30% increase in the number of windings they could put in the same space, increasing the power output over the standard round wire motor.
The company used the new design to develop the prototype motor, which has a maximum rotation speed of 12,000rpm, continuous output of 45kW, maximum output of 80kW and maximum torque of 200N·m. It measures 250 (W) x 194 (H) x 355mm (D) and weighs about 60kg.
By eliminating rare-earth magnets and combining new processing and optimization, the result is a cheaper motor, which would help to reduce costs of EVs and hybrids alike. Reducing costs would certainly help marketing these high-technology vehicles and help them gain acceptance in such a difficult market.