Star connection of grid connected single phase VSIs to supply unbalanced or nonlinear loads under normal and fault condition considering the transmission line impedances

This paper presents a proposed circuit topology and control system to supply both linear and nonlinear loads under unbalanced conditions of the grid voltage and fault conditions by using three, single phase, star connected VSIs and a proposed load current controller. The main contribution is the capability of the proposed controller to supply unbalanced and nonlinear loads and reduce the grid voltages and currents ripple using simple PI controller. Moreover, the proposed topology of connection of three singlephase inverters gains the advantage of parallel connection of VSIs.