Interval-by-Interval Analytical Design of a Dual Active Bridge Converter Under Single Phase Shift Modulation

This paper presents the comprehensive design, analytical modeling, and simulation validation of a dual active bridge (DAB) converter for bidirectional power interfaces in microgrid applications. The proposed analysis is developed under single phase shift (SPS) modulation and is based on the voltage applied across the leakage inductance of the high-frequency transformer (HFT), from which the interval-by-interval evolution of the current is derived. This formulation allows the main electric variables of the HFT to be obtained analytically, including the transferred power, average output current, output power, and RMS current stress. The proposed sizing procedure also considers different operating cases according to the power flow direction and the voltage relation between the high- and low-voltage (HV and LV) DC buses. Particular attention is given to the sizing of the DC bus capacitors, whose capacitance and RMS current requirements are determined based on charge variation and the allowable voltage ripple. The analytical results are validated using a PSIM simulation model under both HV-to-LV and LV-to-HV power flow, including operation under a significant voltage mismatch condition. In addition, calculated and simulated results are reported for all four operating cases, demonstrating good agreement between the analytical formulation and the converter’s simulated behavior.