A Generalized Passivity-Based Stability Criterion for Assessing Large Signal Stability of Interconnected DC Power Systems

Abstract

With the growing need to support large dynamic electric loads in microgrid environments, there has been a necessary push toward highly regulated dc distribution through power electronics. Unfortunately, these systems are nonlinear by nature and provide potentially destabilizing behavior at their source interfaces. To complicate matters further, many systems are built from independently designed subcomponents with little information shared between designs. It is, therefore, necessary to have stability-driven design requirements for each subsystem to enforce stable dynamics upon system integration. Traditional techniques are currently limited to either overly conservative large signal small-gain methods or small signal transfer function approaches that are unreliable for assuring large signal stability. This article proposes a generalized passivity-based stability criterion that conservatively estimates the domain of stability for an integrated nonlinear system. Through passivity partitioning and uniquely driven domain of passivity estimation techniques, this methodology provides interface conditions that certify stability while only requiring a reduced subset of knowledge of each connected subsystem <bold xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">.</b>