Fault Scenarios and Protection Challenges in Multiport Partial Power Converters for PV-Battery Integrated DC Microgrids

Partial Power Converters (PPCs) offer high efficiency by processing only a fraction of total power, yet multiport solutions remain limited. This paper presents a multiport power converter (MPC) enabling coordinated integration of PV, battery, and dc microgrid ports in a 350 V system. The design employs a current-fed push-pull structure with decoupled port-control variables, enabling simultaneous MPPT for the PV port and droop regulation for the battery. A unified fast fault-protection scheme is introduced to handle short-circuit and open-circuit faults, supported by experimental validation under PV-side fault events. Furthermore, the paper discusses the internal inrush currents that arise during mode transitions and outlines measures to prevent device overstress. Both simulation and hardware results validate the effectiveness of these strategies, demonstrating the suitability of the MPC for advanced dc microgrid applications.