Flexible strategy for active and reactive power control in grid connected inverter under unbalanced grid fault

Low voltage ride through (LVRT) requirements make an important challenge for grid connected converters during faults. This paper proposes a flexible control method for grid-connected converters under fault occurrences. This method is presented in a stationary reference frame; thus, a Phase Lock Loop (PLL) is no longer needed. In this method, the output current distortion and power oscillation during the fault will be controlled. Also, the active and reactive power fluctuations during the fault will be controlled independently. Thus, the Control system can be optimized for a variety of desired applications in order to reach the control objectives. The proposed method´s performance is analyzed using simulations in Matlab/Simulink environment.