Fuzzy logic based improved active and reactive power control operation of DFIG for wind power generation

The fuzzy-controllers are designed to tune along with the conventional PI-controllers for the vector control of active and reactive power of a wind-turbine driven DFIG under varying wind speed operation to optimize the power generation at specified power-factor. Initially, stator-flux oriented vector control scheme is implemented using tuned active and reactive power Pi-controllers for the rotor-side converter. Then the fuzzy-controllers are also tuned along with conventional Pi-controllers for the generated active power to track more precisely the reference power at specified power-factor in both sub-synchronous and super synchronous modes of operations. The grid-side-converter is controlled in grid-voltage-oriented reference frame using dc link voltage Pi-controller. Hysteresis current controlled based PWM switching of both rotor-side and grid-side converters ensure fast and accurate control of active and reactive power. Simulation results under varying wind conditions reveal that the additional fuzzy-controller improves the performance of variable speed wind power generating system using DFIG.