Power management in four-leg converter interfacing RES with the grid

This paper presents operation of the four-leg three-level Flying Capacitor Converter (FCC) interfacing renewable energy source (RES) with the grid. Such converter with proposed control method enables work in association of electrical grid disturbances by switching all legs separately to stand-alone or grid connected mode of operation, what allows for energy transfer between them. Four-leg FCC with described control method may be treat as DC microgrid supplied from three independent AC sources and RES. Therefore, very popular in last few years, hierarchical control [1] can be adapted to make power management of such system. Paper describe proposed control method and hierarchical control for such solution. Experimental results are shown and discussed.