@article {178, title = {Multiple-input-multiple-output high-order sliding mode control for a permanent magnet synchronous generator wind-based system with grid support capabilities}, journal = {IET Renewable Power Generation}, volume = {9}, year = {2015}, pages = {925-934}, abstract = {This study presents a control design for a grid connected wind energy conversion system based on a gearless PMSG. The generation system structure comprises a three blade turbine, a 2 MW multi-pole PMSG and a full-scale back-to-back frequency converter linked to the utility grid. The proposed control scheme allows following dynamical specifications taking into account operational requirements and ancillary services imposed by the recent grid connection codes, that is, reactive power regulation and fault ride-through (FRT) capabilities. The control actions to be applied during normal grid operation are designed through second-order sliding mode techniques using a two-stage cascade structure. The multi-variable controller designed attains to regulate the active and reactive powers delivered to the grid, minimising the resistive losses into the generator and maintaining important internal variables into the desired range. This controller presents attractive advantages such as robustness against unmodelled dynamics and external perturbations, finite time convergence to the sliding surfaces and chattering mitigation. To endorse the controlled system with FRT capabilities, a switching control scheme based on voltage grid measurements is also proposed. The performance of the whole control approach is analysed through representative simulations which include parameter variations, external perturbations and three-phase voltage dips.}, keywords = {active power regulation, blade turbine, blades, chattering mitigation, control system synthesis, external perturbation, fault ride-through capability, frequency convertors, FRT capability, full-scale back-to-back frequency converter, gearless permanent magnet synchronous generator, grid connected wind energy conversion system, grid support capability, machine control, MIMO systems, multiple-input-multiple-output high-order sliding mode control design, multipole PMSG, multivariable control systems, multivariable controller design, permanent magnet generators, permanent magnet synchronous generator wind-based system, power convertors, power generation control, power generation faults, power grids, power system measurement, reactive power control, reactive power regulation, resistive loss minimization, second-order sliding mode technique, switching control scheme, synchronous generators, variable structure systems, voltage control, voltage measurement, wind power plants, wind turbines}, issn = {1752-1416}, doi = {10.1049/iet-rpg.2014.0417}, author = {Valenciaga, Fernando and Fern{\'a}ndez, Roberto. D.} } @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 = {

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.

}, 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 {115, title = {2-sliding active and reactive power control of a wind energy conversion system}, journal = {Control Theory Applications, IET}, volume = {4}, year = {2010}, month = {November}, pages = {2479-2490}, abstract = {

This study presents the control of a variable-speed wind energy conversion system based on a brushless doubly fed reluctance machine. The control objectives are the tracking of the maximum power conversion point and the regulation of the reactive power injected by the generation system into the grid. The control design is approached using multi-input second-order sliding techniques which are specially appropriate to deal with non-linear system models in the presence of disturbances and model inaccuracies. The controller synthesised through this theoretical framework presents very good robustness features, a finite reaching time and a chattering-free behaviour. The performance of the closed-loop system is assessed through representative computer simulations.

}, keywords = {2-sliding active power control, 2-sliding reactive power control, brushless doubly fed reluctance machine, brushless machines, chattering-free behaviour, closed loop systems, closed-loop system, control design, control system synthesis, controller synthesis, generation system, grid, maximum power conversion point tracking, multiinput second-order sliding technique, Nonlinear control systems, nonlinear system model, Power conversion, power generation control, reactive power control, reactive power regulation, reluctance machines, representative computer simulation, variable structure systems, variable-speed wind energy conversion system, wind power}, issn = {1751-8644}, doi = {10.1049/iet-cta.2009.0437}, url = {http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=5645800}, author = {Valenciaga, Fernando and Evangelista, Carolina A.} } @conference {100, title = {Active and reactive power control of a brushless doubly fed reluctance machine using high order sliding modes}, booktitle = {Electrical Machines, 2008. ICEM 2008. 18th International Conference on}, year = {2008}, month = {Sept}, abstract = {

This article develops a decoupled active and reactive power control for a variable-speed constant-frequency (VSCF) power generation system based on a brushless doubly fed reluctance machine. This machine is a forthcoming low cost candidate for applications with limited variable speed requirements such as pumping and wind generation. Basically, it allows the use of a partially rated power electronic converter and, at the same time, offers a reliable and maintenance-free operation because of its brushless feature. The control design is approached through second order sliding mode techniques. This theoretical framework permits to deal with systems described by perturbed nonlinear dynamic models, obtaining simple controllers with a finite time reaching phase and a chattering free behavior. The controller performance is assessed through exhaustive simulations.

}, keywords = {active power control, brushless doubly fed reluctance machine, brushless machines, chattering free behavior, Converters, Costs, high order sliding modes, machine control, perturbed nonlinear dynamic models, Power conversion, power electronic converter, Power electronics, Pumps, reactive power control, reluctance machines, Sliding mode control, variable structure systems, variable-speed constant-frequency power generation system, Wind energy generation, Wind power generation}, doi = {10.1109/ICELMACH.2008.4799959}, url = {http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=4799959}, author = {Valenciaga, Fernando} }