MOSFET Noise Source-Based Closed-Form Solution for Mixed-Mode Conducted Emission EMI Noise in a Single-phase PFC

This paper presents two closed-form solutions for solving mixed-mode conducted emission electromagnetic interference (EMI) in a single-phase totem pole boost power factor correction (PFC) converter rated for $120 \mathrm{VAC} / 400 \mathrm{VDC}, 1 \mathrm{~kW}$. From an equivalent MOSFET noise source model, a system of fully implicit differential equations is derived for numerical approximation of all node voltages, with the MOSFET gate voltage and channel currents being approximated by Fourier-Series expansion. In the first closed-form solution, the switched-node voltages are approximated by superimposing internal MOSFET voltage response onto an ideal switched-node voltage waveform, approximated by Fourier Series expansion. In the second closedform solution, an analytical relation based on the MOSFET transconductance is instead used to solve directly for the switchednode voltage. The fully numerical approximation model demonstrates a low average error of $6.85 \%$ and $10.72 \%$ in estimation of six critical noise amplitudes in the measured DM and CM EMI spectra of the converter. The mixed-numeric and analytical model, on the other hand, demonstrates a slightly higher average error of $\mathbf{7. 3 0 \%}$ and $\mathbf{1 0. 7 4 \%}$.