Nanocrystalline Shield in Inductive Power Transfer Pads for EV Charging Applications

Aluminium plates are commonly used in inductive power transfer (IPT) pads to reduce unwanted leakage, enhance mechanical stability, and mitigate heating effects on electric vehicle (EV) chassis. However, using aluminium reduces magnetic coupling for circular IPT couplers. As such, more apparent power is required to realise equivalent real power transfer to the EV battery. These drawbacks can be alleviated by using a nanocrystalline shield due to its lower electrical conductivity and superior magnetic permeability. This paper analysed several nanocrystalline shields based on a designed reduced ferrite structure, considering both integrating the nanocrystalline into the pad enclosure and using it to replace the conventional aluminium backing plate. The results show that the designed IPT pads with reduced ferrites and nanocrystalline shields achieve improved coupling and reduced weight compared to conventional full ferrite configurations.