Identification of Essential Coupling Path Models for Conducted EMI Prediction in Switching Power Converters

A knowledge of conducted electromagnetic interference (EMI) generation and propagation mechanisms can aid the engineers working in the field of electromagnetic compatibility (EMC). This paper presents a method, called essential coupling path models, to investigate the conducted EMI coupling in switching power converters. Three modes of conducted EMI noise: the mixed-mode (MM), the intrinsic-differential-mode (IDM), and the common-mode (CM) are identified by time domain measurements associated with an ac-dc half-bridge converter. The derived models assume that the lumped parameters´ circuits represent the noise generation and propagation paths that allow easy physical interpretations. The experimental results show good agreement by the comparison of measured and predicted MM, IDM, and CM noise emissions with filter included. The proposed method is easy to apply in practice for understanding, diagnosis, and evaluation of EMI behavior