Determination of winding losses of high frequency planar-type transformer using finite-element method

At high frequency the winding losses of the power transformer due to skin and proximity effects becomes a significant component in the loss calculation of the transformer efficiency. This paper examines the winding losses associated with these effects for planar-type low-profile transformers that are suitable for high frequency power supply application. The transformer winding AC resistance and leakage inductance are investigated for the different winding arrangements. 2D and 3D finite-element methods are used to study the flux density distribution in the transformer window area and the current density distribution in the winding conductors.