Power-Angle Synchronization for Grid-Connected Converter With Fault Ride-Through Capability for Low-Voltage Grids

In this paper, the power-angle synchronization control of a grid-tied bidirectional dc-ac converter is investigated for low-voltage grids. The power flow equations for the low-voltage grid are analyzed and compensators are designed to ensure the decoupled control of active and reactive power. The proposed control system operates without the need for a phase-locked loop during balanced and unbalanced grid conditions. It is shown that during balanced conditions the compensators ensure stable operation controlling the desired power flow to and from the grid. It is also demonstrated that the compensators are immune to grid fluctuations and to a large extent can cater grid unbalanced conditions. Experimental results verify the performance of the proposed control scheme.