LPRS analysis of sliding mode buck converter

DC-DC buck (step-down) converters are widely used in various power systems. An exact analysis of buck converter dynamics based on the locus of a perturbed relay system (LPRS) is proposed. Beside conventional analysis tasks - determination of the frequency and amplitude of the self-excited oscillations (chattering), which characterize ripple of the converter output signal - analysis of the propagation of source voltage fluctuations is presented. The latter is conveniently done through the same LPRS method. The results are supported by simulations with the use of the conventional model of the converter.