Current Distribution Control Design for Paralleled DC/DC Converters Using Synergetic Control Theory

In this paper we present an overview of the synergetic control theory and consider a general case of an m- paralleled buck converter system feeding a dependent current source, which can easily represent resistive, constant current, and constant power loads. For control design, we use synergetic control theory, which is based on ideas of self-organization. The theory allows designers to derive analytical control laws for nonlinear, high-dimensional, and multi-connected systems. The derived general analytical nonlinear PI control algorithms for the system under droop current sharing nullities steady state current sharing error, improves voltage regulation and limits maximum current withdrawn from each converter. The paper analyses the stability of the closed loop system under both small and large deviations and clarify the choice of control law coefficients. We illustrate the capability of the synergetic control to maximize the system efficiency by means of coordinative control that changes the number of operating converters. The simulation results presented in the paper show good agreement with the theory.