A Reconfigurable Test Bed for Experimental Studies on Islanded Hybrid AC/DC Microgrids

Abstract

This paper presents a test bed for experimental studies on standalone hybrid AC/DC microgrids. The test bed is comprised of an AC subgrid and a DC subgrid that are interfaced through an interlinking converter (IC). The AC subgrid integrates a number of identical voltage-source converter (VSC) modules, while a number of identical bidirectional DC/DC converters are integrated within the DC subgrid. The test bed is designed to be reconfigurable, flexible, and scalable. For each subgrid, all modules employ a reconfigurable firmware, which allows any module of either subgrid to emulate an arbitrary type of distributed generation (DG), such as PV-based generation, wind-based generation, energy storage, or controllable load. Furthermore, each module has the flexibility to employ an arbitrary type of controller implemented by the firmware, such as droop controller or constant-power controller. The test bed is also highly-scalable, as additional modules can be integrated in either subgrid, thanks to the plug-and-play feature of the test bed. The IC can be controlled to allow autonomous power exchange between the AC and DC subgrids, ensuring proportional load sharing among all DGs connected to the hybrid microgrid. The capabilities of the test bed are demonstrated using a number of test scenarios and elaborating on the experimental results obtained.