Current Control of a Three-Phase Grid Connected Voltage Source Converter Using Vector Control Strategy under Unbalanced Grid Conditions

This paper presents the current control of a three-phase grid connected voltage source converter with LCL filter using vector control strategy under unbalanced grid conditions. The conventional voltage source converters are effective when an asymmetric fault occurs. When three-phase unbalanced grid fault occurs, the unbalanced currents and grid voltages give rise to uncontrolled oscillations in the active and reactive powers which are delivered to the network. To avoid this problem, the new control strategy proposed in this paper. This strategy controls the unbalanced currents and voltages in the converter which are injected to the grid and avoid the uncontrolled oscillations in the network effectively. Using simulation results, the proposed control strategy for a three-phase grid connected converter is proven to be reliable and more effective.