Parameter Extraction Technique for Evaluation of Inductive and Capacitive Elements of Three-Winding Coupled Inductor

Abstract

Wide band gap devices have enabled miniaturization of the magnetic components to enhance the power density of the converter. However, parasitic components become dominant at higher switching frequencies that actuate unwanted electromagnetic interference issues. Therefore, it is critical to model and evaluate them in compact magnetic structures. Since multiwinding coupled inductive structures are essential part of multiphase converters, this paper introduces a measurement method to compute the parasitic elements of a three-winding coupled inductor. Results of the proposed method are verified by measuring the high-frequency emissions of the high stepup converter with two inductor structures. Both inductors had similar inductances but different physical dimensions. With application of the proposed measurement methodology, parasitic capacitances of both inductors were computed. Results showed that one inductor structure has higher parasitic capacitance than the other. Since, high-frequency emissions of the converter directly depends on the parasitic capacitance of the inductor structure, emission profile of the converter showed that converter indeed had lower noise peaks when inductor with lower capacitance was employed. Hence, these results validate the capacitance trend as predicted by the proposed modeling technique. This method can be employed to any multiwinding coupled inductor to compute its parasitics to optimize the required EMI filters.

Parasitic Capacitive Couplings in Medium Voltage Power Electronic Systems: An Overview

“…In order to quantify the characteristics (or capacitive couplings) after the first resonant frequency/antiresonant frequency, the behavioural-based modelling method can be applied [46], which however, requires manufacturing prototypes first and then measuring the time-domain or frequency-domain response. Chokes and multi-phase inductors are more complex than single-phase inductors [49], [202], where more capacitive couplings should be taken into consideration due to the increased number of terminals.…”

A Comparative Study on Parasitic Capacitance in Inductors With Series or Parallel Windings

“…Passive components are essential in power electronics converters [1], [2]. For the converters utilizing wide-bandgap devices [3], [4], the parasitic capacitance in magnetic components, including inductors [5], [6], transformers [7] and motors [8], is of significant importance due to the fast switching characteristics (high dv/dt value) of the wide-bandgap devices [8], [9]. It is reported that such parasitic capacitance can significantly contribute to the capacitive current during the switching transients [10] and may result in increased conducted noise and extra switching losses dissipated by the transistors [11]- [14].…”

EMC Implications of Implementing WBG Devices in Battery Charger Modules for Electric Vehicles

“…Moreover, if the full fast switching capability of GaN switches were employed, EMI emissions would be drastically increased in comparison to the case of Sibased converters under similar operating conditions. Authors of [9] also concluded that by the use of WBG switches in cascaded boost converters, higher EMI is generated in a high frequency spectrum, and it is emphasized that for converters with WBG switching devices more attention needs to be paid to methods to reduce the ringing and parasitics in the circuit for EMI reduction [10].…”