Improved Analytical Calculation of High Frequency Winding Losses in Planar Inductors

Due to the skin and proximity effect, the winding losses of planar inductors under high frequency working conditions increase. The complex of rectangular conductor makes the calculation of AC resistance difficult. And the conventional Dowell's one-dimensional model, which is currently used for the calculation of rectangular conductor's conductive losses leads to a considerable error due to the ignorance of edge effect. To eliminate the error, this paper proposes a two-dimensional analytical calculation model based on the electromagnetic theory, which takes the edge effect into consideration, and establishes a new electromagnetic field model to determine the two-dimensional boundary values. At last, the theoretical calculation method of high frequency copper loss based on planar inductor's winding is derived from single rectangular conductor to multilayer planar windings. The finite element simulation verifies the correctness of the calculation results of the two-dimensional model and has high engineering precision.