DC-link transient improvement of SMC-based hybrid control of DFIG-WES under asymmetrical grid faults

This paper presents the design and analysis of a hybrid controller for a doubly fed induction generator to be employed in a wind energy system. Proposed controller gives the quick dynamic and good transient response during asymmetrical faults as well as sudden changes in wind speed. The proposed technique also help in minimizing DC-transients during grid faults and is capable to extract the maximum power from wind. Further performance of proposed hybrid controller has been analysed independently with sliding mode control (SMC) and proportional and integral (PI) control as its components. It is observed that SMC gives better performance compared with PI in terms of flux ripples, torque ripples, settling time, and DC-transients. The proposed technique is implemented in hardware in loop-based OPAL-RT and MATLAB/SIMULINK environment at a rating of 5.5 KW system under single-line-to-ground and line-to-line fault and with variations of wind speed.