Analysis of a Sliding Mode DC–DC Boost Converter Through LPRS of a Nonlinear Plant

Abstract

An exact analysis of sliding mode boost converter dynamics based on the locus of a perturbed relay system (LPRS) method is presented in this article. An LPRS representation of the dc–dc boost converter based on a full nonlinear model is developed. This is a first known attempt to apply the LPRS concept to an industrial process having a nonlinear model. The frequency and amplitude of the self-excited oscillations (chattering/ripple) are analyzed through the LPRS method. The LPRS is also used to analyze the effect of the propagation of an external disturbance (fluctuations in the source voltage). It is found that the effect of source voltage fluctuations on the system dynamics can be attributed to a combination of the effects of amplitude modulation and input signal propagation. Further, LPRS is used in the design problem of the dc–dc boost converter prototype to determine the required controller hysteresis value which ensures the desired operating switching frequency. Simulation and experimental results are presented to validate and illustrate the theoretical analysis.