Dynamic modeling and analysis of the bidirectional DC-DC boost-buck converter for renewable energy applications

Abstract

This paper focuses on the modeling, dynamic analysis, and simulation of the bidirectional DC-DC boost-buck power converter. The switching sequence applies different duty cycles in the input and output stages, resulting in full regulation of the system variables. By using this strategy, the input stage can be regulated disregarding perturbations in the output leg, as well as the output stage can be controlled independently of the effects of disturbances in the input part; which gives significant robustness to the converter. Based on the switching actions, the state-space average equations are derived, accomplishing the base to obtain the small-signal equations and equivalent small-signal circuits. The open-loop transfer functions are developed, besides the input and output impedance, and the audio susceptibility. Simulation results indicate that the proposed model can predict the dynamic behavior of the system in a wide range of the frequency spectrum, and the results in the time domain are in perfect agreement with the model predictions under disturbances of the control variables, variations of the value of the supply voltage and load changes.