Optimal control of three-phase PV inverter under Grid voltage unbalance

Typical three-phase PV inverter is designed to operate under balanced grid voltage conditions. At low voltage distribution grid, beyond utility power meters, grid unbalance conditions can be often found. Under grid voltage unbalance, a typical three-phase PV inverter with conventional control exhibits poor performance resulting in potential loss of power, long term reliability issue due to power oscillations in the DC bus, potential AC current overloading and over current tripping. This paper presents optimal control of three-phase PV inverter under grid voltage unbalance.