Modeling and Control of Dual-Active-Bridge Converter for Grid-Connected PV System

This paper proposed a phase shift modulation strategy and closed-loop control for an isolated and highly efficient bidirectional converter for a single-phase grid-connected photovoltaic plant. The Dual Active Bridge (DAB) converter is modeled which comprises of input active bridge, a series leakage inductance, a High-Frequency transformer (HFT) and a synchronous rectifier. The modulation strategy keeps the phase shift which allows a two-way power flow between the photovoltaic source and the grid and allows the converter to work with any grid voltage and frequency without a change in the converter structure. A PI controller is employed to control the DAB converter. The unity power factor is achieved at the grid side by keeping the reactive power current component as zero. Time-domain simulation studies have been performed in MATLAB/SIMULINK in order to verify the efficiency of the proposed system topology with the robust control mechanism.