Intelligent Control of DFIG Using Sensorless Speed Estimation and Lookup Table-Based MPPT Algorithm to Overcome Wind and Grid Disturbances

Doubly fed induction generator (DFIG) needs to get adapted to situations like rapid change in wind speed and sudden requirement for grid disturbances to meet modern grid rules. The paper explains the design of controllers for MPPT algorithm for the turbine, DFIG converters, and sensorless rotor speed estimation. These intelligent controllers are used to maintain equilibrium in rotor speed, generator torque, and stator and rotor voltages. They are also designed to meet desired reference real and reactive power during the turbulences like sudden change in reactive power or voltage with concurrently changing wind speed. The turbine blade angle changes with variations in wind speed and direction of wind flow and improves the coefficient of power extracted from turbine using MPPT algorithm. Rotor side converter (RSC) helps to achieve optimal real and reactive power from generator, which keeps rotor to rotate at optimal speed and to vary current flow from rotor and stator terminals. For tracking reactive power demand from grid and in maintaining synchronism when grid voltage changes due to fault at a very faster and stable way Grid side converter (GSC) is helpful. Rotor speed is estimated using stator and rotor flux estimation algorithm. Parameters like stator and rotor voltage, current, real, reactive power, rotor speed, and electromagnetic torque are studied using MATLAB simulation. The performance of DFIG is compared when there is in wind speed change only; alter in reactive power and variation in grid voltage individually along with variation in wind speed.