@article {85,
	title = {Active and Reactive Power Control for Wind Turbine Based on a MIMO 2-Sliding Mode Algorithm With Variable Gains},
	journal = {Energy Conversion, IEEE Transactions on},
	volume = {28},
	year = {2013},
	month = {Sept},
	pages = {682-689},
	abstract = {<p>This study proposes a power control strategy for a grid-connected variable-speed wind turbine, based on a doubly-fed induction generator (DFIG) with slip power recovery. The control objectives vary with the zones of operation (dependant on the wind speed), aiming to maximize the active power in the partial load zone and to limit it when operating within the full load zone, while regulating the stator reactive power following grid requirements. The control design, based on the second-order sliding modes (SOSM) and Lyapunov, uses a modified version of the super-twisting algorithm with variable gains which can be applied to nonlinear multiple inputs-multiple outputs (MIMO) systems. The well-known robustness of the sliding techniques, the simplicity of the algorithm, and the adaptive characteristic of its gains are used together in this study to obtain a controller able to deal robustly with the exacting challenges presented by these systems. An additional benefit of the proposal lies in the smoothness of the control action, an important issue regarding applied mechanical efforts. Representative results obtained by simulation of the controlled system are shown and discussed.</p>
},
	keywords = {asynchronous generators, control design, DFIG, doubly-fed induction generator, energy conversion, full load zone, Gain, Lyapunov method, Mathematical model, MIMO, MIMO 2-sliding mode algorithm, MIMO communication, nonlinear multiple inputs-multiple outputs system, partial load zone, Power control, power generation control, power grid-connected variable-speed wind turbine, power grids, reactive power control, Rotors, second-order sliding modes, second-order sliding modes (SM), slip power recovery, SOSM, stator reactive power control strategy, Stators, super-twisting algorithm, variable gains, variable structure systems, Wind power generation, Wind speed, wind turbines},
	issn = {0885-8969},
	doi = {10.1109/TEC.2013.2272244},
	url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=\&arnumber=6582571},
	author = {Evangelista, Carolina A. and Valenciaga, Fernando and Puleston, Pablo F.}
}
@article {88,
	title = {Lyapunov-Designed Super-Twisting Sliding Mode Control for Wind Energy Conversion Optimization},
	journal = {Industrial Electronics, IEEE Transactions on},
	volume = {60},
	year = {2013},
	month = {Feb},
	pages = {538-545},
	abstract = {<p>This work explores an adaptive second-order sliding mode control strategy to maximize the energy production of a wind energy conversion system (WECS) simultaneously reducing the mechanical stress on the shaft. Such strategy successfully deals with the random nature of wind speed, the intrinsic nonlinear behavior of the WECS, and the presence of model uncertainties and external perturbations acting on the system. The synthesized adaptive controller is designed from a modified version of the super-twisting (ST) algorithm with variable gains. The suitability of the proposed strategy is proved by extensive computer-aided simulations employing a comprehensive model of the system emulating realistic conditions of operation, i.e., considering variations in the parameters and including external disturbances. Additionally, a second controller based on the traditional ST algorithm is also designed and simulated. Results are presented and discussed in order to establish a comparison framework.</p>
},
	keywords = {adaptive control, adaptive second-order control strategy, Algorithm design and analysis, CAD, Computational modeling, control system synthesis, Control systems, direct energy conversion, extensive computer-aided simulations, external disturbances, external perturbations, Generators, intrinsic nonlinear behavior, Lyapunov methods, Lyapunov-designed super-twisting sliding mode control, mechanical stress reduction, model uncertainties, Sliding mode control, ST algorithm, suitability strategy, super-twisting (ST), system emulating realistic conditions, Torque, variable gains, variable structure systems, WECS, wind energy conversion optimization, wind power, Wind power generation, Wind speed, wind turbines},
	issn = {0278-0046},
	doi = {10.1109/TIE.2012.2188256},
	url = {http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6153362},
	author = {Evangelista, Carolina A. and Puleston, Pablo F. and Valenciaga, Fernando and Fridman, Leonid M.}
}
