Robust LMI-LQR Control for Dual-Active-Bridge DC–DC Converters With High Parameter Uncertainties

This article presents an improved linear-quadratic regulator (LQR) control based on linear matrix inequalities (LMIs) to optimize the key parameters for the closed-loop control of dual-active-bridge (DAB) converters with high system uncertainty. First, the polytopic model of an uncertain DAB converter is introduced according to the simplified DAB equivalent circuit. LMIs are then used in the improved LQR control to derive the optimized control parameters under the given constraints. An improved LMI-LQR hybrid closed-loop control is adopted with the output current introduced in the control loop to enhance the dynamic performance. The performance of the proposed LMI-LQR is compared with the conventional LQR in terms of transient responses under various load and line disturbances. Both the simulation and experimental results are provided to validate the advantages of the proposed control.