Design and Analysis of Robust Rotor Current Controller for Doubly Fed Induction Generator

In the past decade wind energy systems were developed for efficient energy conversion. Most of the variable speed wind turbine systems include doubly fed induction generator (DFIG). DFIGs are used in electrical grid connected and standalone systems. This paper presents a novel, robust, rotor current controller structure for both grid connected and stand-alone DFIG applications. Controller is designed for the robustness against change in machine parameters, generator speed changes and load changes in stand alone systems. In the heart of controller design lays low pass filter based disturbance observer. Experimental results are provided that verify controller performance in grid connected scenario and stand alone generator scenario (local grid). Experiments are done using 1.1KW DFIG experimental test bed and custom developed switching inverter.