Robust Model Predictive Control for DAB Converters Using Extended Phase Shift Modulation With Minimum Backflow Power and ZVS Design

This paper introduces a method for deriving an optimal closed-form solution for extended phase shift (EPS) control of a dual active bridge (DAB) DC-DC converter, capable of achieving both minimum backflow power (MBP) and zero-voltage switching (ZVS) conditions. First, backflow power, which significantly impacts the converter’s efficiency, is analyzed and minimized using Karush-Kuhn-Tucker (KKT) conditions. By solving an optimization problem with constraints that include power transfer, ZVS, and EPS conditions, the proposed method provides closed-form solutions for the inner and outer phase shifts. Second, based on the KKT solutions and the output filter, robust model predictive control (RMPC) is designed, taking system parameter uncertainties into account. As a result, the closed-loop control can simultaneously adjust the inner and outer phase shifts, facilitating overall performance improvement. This approach ensures that the converter operates efficiently and reliably, reducing power losses and enhancing efficiency. Finally, to validate the theoretical findings, various real-time simulations on hardware-in-the-loop (HIL) 404 devices are conducted. Furthermore, the effectiveness of the proposed method is demonstrated through comparisons with previous works.