A generalized framework for sampled-data model analysis of closed-loop PWM DC-DC converter system

In spite of the fact that, sampled-data models of PWM DC power converter systems (PDCS) are more accurate and natural, little effort has been made to use sampled-data techniques for stability analysis and synthesis of closed-loop PDCS. Instead, averaged models are typically used for control loop design, while detailed simulations are used for validating closed-loop performances. Recent developments in sampled-data control have resulted in new powerful tools for analysis and synthesis of periodic-system. Time lifting of continuous time signals/systems is one of such tools. In this paper, the authors introduce a generalized framework for sampled-data analysis of DC-DC power converter system based on continuous time lifting of signal/system. This framework will provide an adequate ground to tackle the hybrid nature of these systems. It has been shown that the general discrete-time model of a PDCS is equivalent to a time-lifted model for this class of systems and closed loop PDCS local stability problem can be described by an equivalent time-lifted system, which is finite rank linear discrete-time problem. Hence well-established analysis techniques in sampled-data control can instantly be applied for analysis of these systems. A system composed of two parallel buck-converters has been analyzed to demonstrate the proposed framework