DC grid/bus tied DFIG based wind energy system

This paper presents a novel configuration of Doubly Fed Induction Generator (DFIG) based wind energy systems (WESs) to improve the reliability of power systems. In the proposed configuration, rotor and stator sides of DFIG are connected to Direct Current (DC) grid/bus through converter and 12-pulse diode bridge rectifier, respectively, while loads are connected with the Alternating Current (AC) bus. Furthermore, the rotor current amplitude and frequency have been utilized to regulate the voltage of stator AC bus. The RMS detection of load/stator voltage method is used to calculate the reference rotor currents. The control pulses for rotor side converter are supplied by the hysteresis current controller, operated on the error signal, calculated between actual and reference rotor currents. Also, a comparative study between the speed-sensorless control and speed-sensor control techniques is presented for the rotor side converter of the proposed configuration. Furthermore, three possible cases, namely, 'step change in reference input voltage', 'step change in wind speed or wind gust', and load switching are simulated in MATLAB® for2 MVA DFIG based WESs connected to DC grid/bus to evaluate the proficiency of the proposed configuration. Also, proposed configuration is tested on experimental set-up to reveal its efficacy in real environment.