Flatness-Based Control for Transient Current Suppression in a Dual Active Bridge Converter

This paper proposes a non-linear controller that aims to suppress AC transient current overshoots. The controller is compatible with any generic Triple Phase Shift (TPS) modulation and utilizes a dynamic model based on fundamental component analysis. It uses a flatness-based current regulator and multiple time-scale cascaded control. The approach is unique as it can effectively suppress AC current overshoots related to input grid transients, and is compatible with most efficiency optimization schemes. Additionally, it achieves immunity to fast, large signal operating point variations. The article first presents the control-system structure, then develops controller equations. As an example, it is coupled to a state of the art algorithm minimizing DAB RMS current. The proposal is validated using MATLAB Simulink for a 150W, 28V-12V design. The target application is in next generation flight computer power supplies where increased integration is crucial.