Generic and Flexible Digital Model of DAB Converters With Various Topologies and Control for Efficient Optimal Design

To evaluate the performance of dual-active-bridge (DAB) converters across various topologies and control schemes for optimal design, this paper proposes a generic explicit digital model applicable two-level (2L)/three-level (3L) half-bridge (HB), full-bridge (FB), and three-phase (3P) topologies with a unified control structure. Voltage and current expressions for a single bridge leg considering both 2L and 3L topologies are developed in a generalized manner, and thus the model of DAB topologies with different number of legs can be constructed by superimposing the corresponding number of individual bridge leg models. Subsequently, the digital model, i.e., discrete-time model of DAB converters with different topologies and control configurations, is derived based on the circuit differential equations and a unified closed-loop control system by applying backward Euler method. Therefore, both steady-state and dynamic performance of DAB converters can be predicted in the proposed model. Owing to the analytical formulation of operating parameters and generic expressions for different topologies and control, the calculation speed of the proposed digital model can be accelerated compared to commercial simulation platforms such as MATLAB/Simulink and PLECS, and the design efficiency can be significantly enhanced, especially when it eliminates the need for frequent manual adjustments of topologies, modulation, and loss-thermal models of power devices. Simulation and experimental tests validate that the digital DAB model can achieve high accuracy under various topologies with fast execution speed.