Disturbances Rejection and Harmonics Reduction of Doubly Fed Induction Generator Based Wind Energy Conversion Systems

摘要

Although the doubly fed induction generator has many advantages over other configurations of wind energy conversion systems, it is not only susceptible to low power quality but also generates some power quality problems, such as harmonics. Proliferation of non-linear loads and high-scale penetration of doubly fed induction generator based turbines in the near future make disturbance rejection and harmonic reduction of these systems important issues. Therefore, this article aims to reduce the effects of the grid power quality problems on doubly fed induction generators and power quality problems caused by the doubly fed induction generator itself To achieve this goal, the capability of the grid-side converter is extended by means of adding an active filtering function based on the voltage-detecting method. By this way, the fatal effects of system voltage disturbances and instantaneous active power oscillations can be reduced. Moreover, the proposed system is capable of damping out harmonic propagation phenomenon that is of great concern in offshore wind farms. In this system, to reduce harmonics emission of the doubly fed induction generator and further improve of its performance, a noise-shaping modulator, named ∑△, is utilized for modulation of rotor- and grid-side converters. Simulation results demonstrate the efficiency of proposed strategy.