An augmented state observer-based sensorless control of grid-connected inverters under grid faults

The increasing integration of grid-connected renewable energy systems impose major challenges reliability and power quality within grid system. Grid-connected must ensure stability, accommodate low voltage ride-through capability, comply with codes under unbalanced dips to avoid any grid-disconnection. In this context, paper proposes a novel control strategy improve inverter conditions. Positive negative sequence components are estimated using an augmented state disturbance observer. values phase-angle used protect the from over-current tripping even at dips. This can be achieved by reducing active suppressing its fluctuations new current references, which obtained in synchronous reference frame according codes. effectiveness flexibility proposed have been demonstrated numerical simulation validated experiments both balanced fault