Power converter EMI analysis including IGBT nonlinear switching transient model

It is well known that very high dv/dt and di/dt during the switching instant is the major high frequency EMI source. This paper proposes an improved and simplified EMI modeling method considering the IGBT switching behavior model. The device turn-on and turn-off dynamics are investigated by dividing the nonlinear transition by several stages. The real device switching voltage and current are approximated by piecewise linear lines and expressed using multiple dv/dt and di/dt superposition. The derived EMI spectra suggest that the high frequency noise is modeled with an acceptable accuracy. The proposed methodology is verified by experimental results using a DC-DC buck converter.