Time Domain Analysis of Isolated Buck (F1y-Buck) Converter

This paper presents a comparative study of time domain analysis of multi-output isolated buck (fly-buck) converter with and without considering the effect of parasitics in continuous conduction mode. Time domain analysis of fly-buck converter has been performed to study the transient and steady state behavior of a converter in a faster and more accurate manner. It constitutes the derivation of mathematical expressions for the parameters like inductor currents, capacitor voltages and output voltages in each mode by various methods such as expansion of state transition matrix as a power series, modal decomposition method etc. The inductor current waveforms obtained by plotting the derived mathematical expressions from time domain analysis in MATLAB, are compared with the waveforms obtained from PSpice simulation and percentage errors are calculated for each mode. The PSpice simulation of a 5W fly-buck converter operating with a switching frequency of 100 kHz is carried out to substantiate the analysis carried.