Fault ride-through of grid-connected THIPWM fired DCMLI-based DFIG using parallel switched feedback-controlled DVR

The proposed approach shows that the DCMLI systems generate a near sinusoidal voltage with reduced total harmonic distortion (THD). The power quality of the DFIG system is upgraded. A modified feedback control technique of DVR is pivotal to improve the capability of FRT in WECS based on DFIG like voltage sag, dip, swell, active and reactive power support with no tripping in the DFIG. It also achieves a flexible control solution for balanced and unbalanced fault conditions. The modified feedback DVR control overcomes any fault conditions that occur in the grid. The proposed system with DVR showed to be stable, very effective and verified. The main feature of using such combined control is verified through MATLAB/Simulink based simulation results of a 1.5'.MW grid-connected WECS based on DFIG. It has been verified under different operating conditions based on wind speed to test THD levels and under different fault conditions, to test ride-through capabilities. The results showed good power quality performance and good FRT capability during various fault scenarios. The results are compared to the recently updated grid code standards, which make large wind farms to be treated, in the future, like conventional power plants.