Investigation of DC-DC Converter Modeling

Stability is a prime concern in any dc voltage regulation system. However, closed-loop stability is not always guaranteed if a low-pass filter is present at dc-dc converter input. In this thesis small-signal transfer functions based on averaged modeling techniques are exploited to systematically formulate some design rules to avoid instability. Further, averaged modeling techniques are evaluated in this way as an effective tool for analyzing dynamic behavior of dc-dc converters and for acquiring physical insights into various dynamical phenomena. State-space averaged models are widely accepted in practice mainly because of their simplicity, generality and demonstrated practical utility. This research attempts to explore their capabilities and limitations especially from control perspective. One of the key contributions is the theoretical and experimental investigation of averaged modeling in Discontinuous Conduction Mode (DCM). In order to resolve the filter-converter instability issue, both passive and active solutions are profoundly studied in this work and a control solution based on full state-feedback with pole-placement technique is proposed.