Levenberg-Marquardt SMC control of grid-tied Doubly Fed Induction Generator (DFIG) using FRT schemes under symmetrical fault

The variable speed Doubly-Fed Induction Generator (DFIG) is widely deployed in Wind Energy Conversion System (WECS). Levenberg-Marquardt Sliding Mode Controller (LM-SMC) is applied to Grid Side Converter (GSC) that ensure voltage regulation of DC-Link capacitor during symmetrical transmission line faults. Moreover, hardware solutions are implemented, namely STFCL and DC-Chopper to enhance the FRT capability during balanced grid faults. DC-chopper is connected in parallel with DC Link capacitor for prevention of rapid fluctuations in DC-link voltage, while the STFCL is a stator switch having ability to protect the back to back converters from inrush currents and overvoltages during grid faulty condition as well as turbine gearbox from over torque. The validity of the proposed controller and topologies are verified using simulation analysis of 1.5MW DFIG (9MW grid-connected system) prototype in MATLAB/Simulink. The results of LM-SMC controller improved with FRT schemes are critically compared with typical tuned Proportional Integral Derivative (PID) controller.