Stability analysis of a Buck converter with input filter based on an LPV formalism

Abstract

This paper presents stability analysis of a Buck converter based on an LPV (Linear Parameter-Varying) approach. Theoretical stability analysis of DC-DC converters is not so easy especially with wide variations of input voltage and load. Authors propose a theoretical method that can be used by converter designers. A nonlinear model of buck converter is proposed to achieve stability analysis. The main control law is based on a state-feedback. The input voltage and load power variations are specified in ranges and variations can be as fast as possible. LPV analysis of a PI-feedback and a state-feedback are compared to show drawbacks of conventional PI-feedback. Simulation results are presented to verify stability analysis. They are based on two model levels: a nonlinear averaged model and a switched model.