Optimal control allocation for the parallel interconnection of buck converters. (April 2021) - Kreiss, Jérémie
Abstract: This paper presents a control algorithm for the parallel interconnection of heterogeneous power converters. A single resistive load is assumed to be fed by an arbitrary number of buck converters via a common DC bus. The approach is based on control allocation theory and a constrained quadratic optimization algorithm. The strategy achieves a fast voltage response with an optimal current distribution among the converters, while taking into account the current limits, the dynamic response, and the efficiency of the individual converters. An interesting by-product of the approach is the ability to put converters in and out of service through trivial adjustments of the code. The benefits of the approach are assessed through simulations and an experimental evaluation. Highlights: For the parallel interconnection of buck converters, the proposed method ensures a fast response while maximizing efficiency by a free distribution of currents, including transients. The proposed method guarantees stability under certain conditions with consideration to load uncertainty, converter dynamics, and input and current limits. The proposed method facilitates the predictable connection and disconnection of converters in real-time to accommodate large load variations or for maintenance.