The design of efficient MHz cored magnetic components that concurrently conduct current at multiple frequencies is a very challenging design task. With the growing popularity of inductive power transfer, particularly at MHz, such inductors become crucial parts of the primary coil driver circuitry, and given the incredibly low losses in GaN devices, dominate the losses. In this work, we design and integrate a custom distributed gap inductor into the φ-branch of a 13.56 MHz, 70 W Class EF2 inverter, which conducts significant current at the fundamental, second and third harmonics. We quantitatively evaluate its performance by conducting a comprehensive comparison with a variety of air-core and ferrite core inductors. The power losses in our modified pot inductor were less than half that of a variety of matched air-core and cored inductors, which resulted in over 4% relative increase in system efficiency.
