NdₓFe₁₋ₓNy Magnetic Core Application for Resonance Coil of 13.56 MHz GaN Wireless Power Transmission

In this study, the NdₓFe₁₋ₓNy materials are applied for the magnetic core of the series resonance circuit of GaN wireless power transmission (WPT) for the first time. At over 10 MHz, the inductance of the fabricated Nd₂Fe₁₇N₃ coil is stable at 1.15 μH and the effective magnetic permeability of the Nd₂Fe₁₇N₃ is estimated to be 2.6. At the same inductance, the number of turns of the Nd₂Fe₁₇N₃ coil can be decreased as compared with that of the air-core coil, and the coil size can be reduced by 0.7 times by using the Nd₂Fe₁₇N₃ material. At the 13.56 MHz GaN-WPT operation, the successful WPT waveforms can be obtained, and the drastic reduction of the energy loss at the coil is achieved due to the low imaginary part of the magnetic permeability. The Nd-Fe-N materials are considered indispensable to GaN high-frequency switching circuits.