N-Conductor Passive Circuit Modeling for Power Converter Current Prediction and EMI aspect

Roberto Mrad (1) , Florent Morel (1) , Gaël Pillonnet (2) , Christian Vollaire (3) , Philippe Lombard (4) , Angelo Nagari (5)

1 EE - Ampère, Département Energie Electrique
2 INL - CSH - INL - Conception de Systèmes Hétérogènes
3 MIS - Ampère, Département Méthodes pour l'Ingénierie des Systèmes
4 INL - LOCI - INL - Lab-On-Chip et Instrumentation
5 STMicroelectronics

This paper proposes a method to study the impact of passive circuits such as filters, loads, and board layout on conducted electromagnetic emissions. The method is dedicated to power converters with N active conductors and a ground conductor, followed by passive circuits. A sophisticated use of impedance matrices allows high frequency current prediction. The power system is divided into functional circuits called blocks. Each passive block is modeled by an impedance matrix. A fast matrix calculation permits association of those matrices to obtain a compact model represented by an impedance matrix. Knowing the converter output voltages and the resulting impedance matrix, currents are calculated to study the influence of each passive block on high frequency current spectrum, and so the EMI (electromagnetic interference). This will help for filter and board layout design for a given load. After presenting the general use of the method, the validation is performed on a differential Class-D audio amplifier used in cell phone applications. The practical application on a two-active conductor system validates the method up to 110 MHz.

Mots clés: current prediction; Impedance matrix; Passive circuit modeling; Conducted EMI; Class-D amplifier

Domaines: Electronique

Roberto Mrad, Florent Morel, Gaël Pillonnet, Christian Vollaire, Philippe Lombard, et al.. N-Conductor Passive Circuit Modeling for Power Converter Current Prediction and EMI aspect. IEEE Transactions on Electromagnetic Compatibility, 2013, 55 (6), pp.1169-1177. ⟨10.1109/TEMC.2013.2265048⟩. ⟨hal-01103586⟩