Inductance Calculation Method Considering the Window Effect of Planarized Magnetic Core

Inductors with planarized magnetic cores and printed circuit board (PCB) windings are becoming more popular with the development of high-frequency, high-power-density power converters. The magnetic flux distribution in an inductor is affected by the geometry of the magnetic core and windings, which in turn affects the inductance value of the inductor. The accurate inductance calculation method is proposed for PCB-winding planarized inductors. The window effect and shielding effect, which can be recognized as the impact of planarized winding area, PCB winding, and operation frequency on the real inductance of an inductor, are revealed in this article. The impact of the fringing effect, window effect, and shielding effect is analyzed in-depth based on which an improved inductance calculation model is proposed. According to the calculation, finite-element analysis simulation, and experimental tests of various planar inductor samples with different winding turns, frequency, and air gap distance, it is verified that the proposed method is more accurate than previous inductance calculation methods.