Study of complex dynamics of DC-DC buck converter

Abstract

Switched-mode power converter circuits are non-linear and time varying in nature. In this work, non-linear dynamics for both voltage- and current-mode-controlled DC-DC buck converter has been investigated through simulation and practical study. The converter is controlled by naturally sampled constant frequency pulse width modulation signals in continuous conduction mode and converter exhibits fundamental, subharmonics and chaotic oscillations for the variation of circuit parameters. In computational study, the model of buck converter is simulated by non-autonomous differential equations and finally the computational waveforms have been verified with experimental results. Here, the main objective of this research work is to study the experimental chaos and to identify the subharmonic and chaotic oscillation zones for specific parameter values that will help the power electronic engineers to design chaos-free power supply. It has been observed that the route to chaos is achieved by period doubling in the buck converter. In order to verify the computational study, laboratory prototype of closed-loop buck converter has been fabricated. The results obtained from simulation and experimental study have been presented and compared.