Start-up Procedure for the Three-Phase Four-Leg Inverter in an AC Battery application

Abstract

Three-Phase Four-Leg Inverter is getting so much attention due to its ability to deal with unbalanced AC voltage sources that can be caused by grid/load faults. Recently, the flexibility of this converter to connect both the 1-phase and 3-phase grid systems in a home battery application has further concern. A vast amount of literature that deals with this topology is exclusively focused on various modulation methods and control structures aimed at optimizing different aspects of its steady-state and/or transient performance. However, no literature is available on its start-up procedure in grid-tied mode which is an indispensable part of the control design of any practical circuit. To fill this gap, in this paper, a three-step start-up procedure for a three-phase four-leg Inverter in an AC Battery is proposed. The primary goal is to ensure that the inrush currents stay below a specific level while the output voltage increases to its reference value with a small overshoot. The proposed start-up procedure is illustrated via Hardware-in-the-loop (HIL) simulation results, which improves the feasibility of future experiments.