Prediction of Resonance Effect on the Common Mode Current Noise

M. Kchikach, A. Menou, J. Elaoufi, A. Elhasnanoui (Morocco), and Z.M. Qian (PRC)


Modelling, Resonance phenomenon, Conducted common mode current noise, simple equivalent circuit model.


This paper presents simplified equivalent circuit model used to study the resonance influence on common mode (CM) current noise in switching mode power supply. Indeed, the Electromagnetic Interference (EMI) caused by a resonance is a critical factor, and is a source of the high conducted EMI that physically affects the tested AC/DC converter used for telecom applications. The analysis and the prediction of its effect are of fundamental importance to avoid system malfunction and to guarantee the satisfaction of EMC standards. The proposed equivalent circuit model contains essential couplings, parasitic elements, and sources occurred in the common mode current path. This series resonance circuit is primarily composed of input cables; equivalent voltage source and the intentional parameters of the converter is examined theoretically. A comparative analysis between practical results and the proposed model highlight good matching.

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