Robust Control Strategies for Enhancement of Power Quality and LVRT Capabilities of DFIG in a Grid Connected System

This paper presents implementation of robust controllers in an MMC-connected DFIG wind farm associated with Power Quality issues and LVRT capabilities under symmetrical faults which in turn improves system efficiency and stability. In this paper a two sequentially connected 5-level MMC modules considered. MMC-I is connected to Rotor, MMC-II is bridged to electric grid, each of them controlled by individual controllers. The classical PI controllers for voltage and current regulation are modernized with evolved controllers like SMC and FOPI modules to amplify durability and response of the control signals. The efficacy of the robust controllers tested on the Simulink model of DFIG connected Wind Energy Conversion System not only sustains a symmetrical fault but also improves DC link voltage. The performance of FOPI controller compared to SMC and conventional PI controller in addressing power quality issues and LVRT enhancement under symmetrical fault condition demonstrated with simulation results.