DETERMINATION OF WINDING LOSSES OF LOW-PROFILE PLANAR-TYPE TRANSFORMER

At high frequency, the winding losses of power transformer due to skin and proximity effects becomes a significant component in the loss cal culation of the transformer efficiency. This paper examines the windin g losses associated with these effects for planar-type low-profile tra nsformers that are suitable for high frequency high density soft switc hing power supply application. The transformer winding ac resistance a nd leakage inductance are investigated for the different winding arran gements. 2D and 3D Finite-element methods are used to study the magnet ic flux distribution in the transformer window area and the current de nsity distribution in the winding conductors.