Bearing Unit with Wireless Power Transfer with SKF

Separately Excited Synchronous Motor (SESM) technology, while representing less than 5% of the EV market currently, offers substantial advantages in reducing CO2 emissions through using less raw materials. SESMs do not require rare-earth magnets and are thus a more sustainable and reliable motor option.

The key to increasing the adoption of SESMs lies in developing a high-speed and reliable electric connection between the rotating shaft and the power electronics of the motor, eliminating the drawbacks associated with traditional carbon brush sticks. High-speed seals are necessary for the brush to work correctly, and this would increase the cost, risk of failures, and friction, which hinders its broader adoption in the EV market. The proposed solution involves a bearing unit as a stiff, precise rotating element facilitating wireless power transmission from the electronics to the rotating shaft.

A module attached to a bearing or bearing assembly must be developed. SKF can provide bearing units or arrangement, allowing optimal mechanical precision and stiffness to position components close to each other, a crucial feature for an efficient wireless power transfer. The automotive industry is cost-sensitive, so scalability in terms of volume and providing enough value to justify the extra cost of the component are crucial considerations. This innovative solution would align with SKF’s strategy of providing engineered solutions with specific weight, positioning the product as more than just a commodity. Additionally, achieving a better CO2 footprint and reducing dependency on magnet procurement aligns with SKF’s sustainability targets and potential future legislation.

The ideal solution should provide a high-speed and reliable electric connection between the rotating shaft and the power electronics of SESMs. It should eliminate the need for traditional carbon brushsticks, resulting in a more dependable and potentially cost-effective solution at the system level. The answer could enable wireless power transmission more reliably and efficiently by utilizing technologies such as inductive or capacitive power transfer and other out-of-the-box concepts such as conductive fluids. This wireless power transmission bearing unit, that is, one or several bearings in a specific arrangement, should be designed to be easily integrated into SESMs without compromising the size of the system. It should be capable of withstanding the demanding conditions of EV applications, and the solution should deliver seamless energy transfer, ensuring optimal performance and efficiency of the SESM throughout its operational lifespan.