Nanocrystalline Core Loss in High Power IPT Systems for EV Charging Applications

Mn-Zn ferrite is commonly used in inductive power transfer (IPT) systems to enhance magnetic coupling and reduce flux leakage. However, ferrite is not ideal for high power transfer due to the large volume of material needed for its low saturation flux density, brittleness, and high core loss leading to thermal issues. Nanocrystalline alloys are potential alternatives to replace ferrite in IPT pads to improve magnetic performance. This paper analyses the core loss and equivalent series resistance (ESR) of ferrite and nanocrystalline cores in high-power IPT pads based on the measurement of magnetic properties using the partial cancellation method. The experimental findings show that the ESR of IPT pads using nanocrystalline cores decreases with higher excitation current in the pads, contrary to the typical behaviour of IPT pads using ferrite.