Control of Multilevel Converter Driving Variable Speed Wind Turbine in Case of Grid Disturbances

This paper proposes modified dual vector current control (DVCC) for the wind turbine application. As in case of conventional DVCC, it fulfills requirements for average unity power factor with suppressed oscillations in active power flow. However, uncontrolled increase in converter output current under unbalanced grid voltage conditions is prevented through imposing limit in its magnitude. Multilevel back-to-back converter is used in order to achieve full control of the turbine, as well as better power quality and lower torque and grid current oscillation