Accurate Calculation of Parasitic Capacitance of High Frequency Inductors

Abstract

High-frequency inductors are important devices in power converters. The parasitic capacitance not only affects the electromagnetic interference suppression effect of filter inductors, but also causes efficiency degradation and other problems. In order to predict the impedance characteristics of high-frequency inductors, this paper proposes a method to accurately calculate the parasitic capacitance of inductors. Firstly, the effect of the winding structure parameters on the electric field distribution between adjacent turns is investigated. Then, the calculation method is optimized, which can be used to accurately describe the electric field distribution. Secondly, the effect of core parasitic capacitance on the total capacitance is further investigated. Finally, a calculation method for the parasitic capacitance of high-frequency inductors is established. In the experiments, the impedance test and finite element simulation are used as references to compare the calculation results. The maximum calculation error is only within 5.05%, which verifies the validity and accuracy of the proposed calculation method.