State-space average Modeling of DC-DC Converters with parasitic in Discontinuous Conduction Mode (DCM)

Abstract

Discontinuous Conduction Mode occurs due to low load current operation of converters which employ current or voltage unidirectional switches.The switching ripples in inductor current or capacitor voltage causes the polarity to reverse of the applied switch current or voltage and thus a zero current mode is reached. Nowadays, converters are so designed,to operate in DCM for all loads due to its higher efficiency and lower losses.In this thesis, we have derived the Reduced Order & Full Order Averaged Models for the Buck and Boost configuration of converters. Also we calculated the output transfer function of boost converter which can be further utilized for designing of controller. Then, parasites effects have been taken into account for Boost Converter and accordingly, its various transfer functions (Control, Output Impedance, etc.) and various bode diagram have been plotted and compared with ideal cases.