Average Model of Boost Converter , including Parasitics , operating in Discontinuous Conduction Mode ( DCM ) A

This paper presents the principles of state-space average modeling of DC-DC Boost converters operating in the Discontinuous Conduction Mode (DCM) which occurs in converters due to low load current operation. The switching ripples in inductor current or capacitor voltage cause polarity reversal of the applied switch current or voltage and thus a zero current mode is reached. Modern converters are often designed to operate in DCM for all loads due to their higher efficiency. In this paper, the reduced-order & full-order average models for the Boost converter are derived. Also, the output transfer function of the Boost converter is calculated which can be further utilized for designing a robust controller. Furthermore, the effects of parasitic elements and losses are included based on the state-space averaging technique. The open-loop transfer functions of the proposed models are derived and the behavior of the Boost converter is verified by analysing transient step responses.