This article classifies, describes, and critically compares different modeling techniques and control methods for dual-active-bridge (DAB) dc–dc converters and provides explicit guidance about the DAB controller design to practicing engineers and researchers. First, available modeling methods for DAB including reduced-order model, generalized average model, and discrete-time model are classified and quantitatively compared using simulation results. Based on this comparison, recommendations for suitable DAB modeling method are given. Then, we comprehensively review the available control methods including feedback-only control, linearization control, feedforward plus feedback, disturbance-observer-based control, feedforward current control, model predictive current control, sliding mode control, and moving discretized control set model predictive control. Frequency responses of the closed-loop control-to-output and output impedance are selected as the metrics of the ability in voltage tracking and the load disturbance rejection performance. The frequency response plots of the closed-loop control-to-output transfer function and output impedance of each control method are theoretically derived or swept using simulation software PLECS and MATLAB. Based on these plots, remarks on each control method are drawn. Some practical control issues for DAB including dead-time effect, phase drift, and dc magnetic flux bias are also reviewed. This article is accompanied by PLECS simulation files of the reviewed control methods.

DC microgrids encounter the challenges of constant power loads (CPLs) and pulsed power loads (PPLs), which impose the requirements of fast dynamics, large stability margin, high robustness that cannot be easily addressed by conventional linear control methods. This necessitates the implementation of advanced control technologies in order to significantly improve the robustness, dynamic performance, stability and flexibility of the system. This paper presents an overview of advanced control technologies for bidirectional dc/dc converters in DC microgrids. First, the stability issue caused by CPLs and the power balance issue caused by PPLs are discussed, which motivate the utilization of advanced control technologies for addressing these issues. Next, typical advanced control technologies including model predictive control, backstepping control, sliding mode control, passivity-based control, disturbance estimation techniques, intelligent control and nonlinear modeling approaches are reviewed. Then the applications of advanced control technologies in bidirectional DC/DC converters are presented for the stabilization of CPLs and accommodation of PPLs. Finally, advanced control techniques are explored in other high gain non-isolated (e.g., interleaved, multilevel, cascaded) and isolated converters (e.g., dual active bridge) for high power applications.

Pulsed-Power-Loads (PPLs) are becoming more common in medium-voltage naval DC micro-grids. To reduce their impact on the electrical system, energy storage elements can be installed. For optimal performance the interface converters need to have fast dynamics and excellent disturbance rejection capabilities. Moreover, these converters often need to have a voltage transformation capability and galvanic isolation since common energy storage technologies like batteries and super capacitors typically operate at relatively low voltages. In order to address these issues a Dual-Active-Bridge converter with a Moving Discretized Control Set Model Predictive Control (MDCS-MPC) is proposed in this paper. The controller has a fixed switching frequency, which allows straightforward filter design. The operating principles of the MDCS-MPC are introduced in this paper with the development of a cost function that provides stiff voltage regulation. Resonance damping and sampling noise resistance have been achieved by an adding additional term in the cost function. This paper presents an assessment of the performance of the proposed MDCS-MPC and comparisons with other control methods. Experimental validation from a 300V/300V 20kHz 1kW Dual-Active-Bridge converter are also presented to verify the theoretical claims.

Pulsed-Power-Loads (PPLs) are commonly incorporated in medium-voltage navy DC microgrids. To mitigate their detrimental effects, energy storage systems (ESSs) can be installed and their converters need to have excellent disturbance rejection capability. To facilitate this objective, a Moving-Discretized-Control-Set Model-Predictive-Control (MDCS-MPC) is proposed in this paper and applied on a Dual-Active-Bridge converter. Fixed switching frequency is maintained, enabling easy passive components design. The proposed MDCS-MPC has a small number of calculating points in each switching period, which enables the implementation in standard commercial control platforms. The operating principle of the MDCS-MPC is introduced in development of a cost function that, on one hand, provides stiff voltage regulation; on the other hand, minimizes current stress. Theoretical claims are verified on a 300V/300V 20kHz 1kW Dual-Active-Bridge.