Coupled inductor Core design methodology to improve power-density for Interleaved buck converter with 22kW-class wireless charging of EV

DC/DC Converter is one of the components of the electric vehicle (EV) wireless charging system. And the inductor occupies a large capacity in the DC / DC converter. It is necessary to design to reduce the size of the inductor to improve the power density of the DC / DC converter. So recently, a coupled inductor is applied to reduce the volume of the inductor. But it was difficult to design the coupled inductor because the unpredictable coupling coefficient plays an important role in the design index when designing a coupled inductor. In this paper, the coupling coefficient is derived from the equation and verified through the 3D finite element method (3D-FEM). In conclusion, the coupled inductor was designed using the coupling coefficient equation. And, it has a smaller volume compared to the conventional single inductor.