@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 {46, title = {LPV Wind Turbine Control With Anti-Windup Features Covering the Complete Wind Speed Range}, journal = {Energy Conversion, IEEE Transactions on}, volume = {29}, year = {2014}, month = {March}, pages = {259-266}, abstract = {

This paper addresses the control of a variable-speed variable-pitch wind turbine in the whole wind speed range. To this end, a linear parameter varying anti-windup (AW) controller is proposed as part of a control structure focused on improving the transition between low- and high-wind speed operations. The control structure is similar to classical PI controls used in commercial wind turbines. However, a more advanced gain-scheduled controller and AW compensation are proposed. As a consequence, the new control scheme is capable of improving the behavior of the wind turbine in the transition zone and provides better stability margins. The proposed control was evaluated in a 5-MW wind turbine benchmark and compared with a classical control scheme. To this end, very demanding and realistic testing scenarios were built using the FAST aeroelastic wind turbine simulator as well as standardized wind speed profiles.

}, keywords = {Anti-windup, anti-windup features, benchmark, control of wind turbines, gain-scheduling control, Generators, linear parameter varying anti-windup controller, linear parameter varying systems, LPV wind turbine control, PI controls, power system control, Proposals, Torque, variable-speed variable-pitch wind turbine, Velocity control, Wind speed, wind speed range, wind turbines}, issn = {0885-8969}, doi = {10.1109/TEC.2013.2294212}, author = {Inthamoussou, Fernando A. and Bianchi, Fernando D. and De Battista, Hern{\'a}n and Mantz, Ricardo J.} } @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 {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 = {

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.

}, 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.} } @article {52, title = {Optimal gain-scheduled control of fixed-speed active stall wind turbines}, journal = {Renewable Power Generation, IET}, volume = {2}, year = {2008}, month = {December}, pages = {228-238}, abstract = {

For a smooth integration of large wind farms into the utility grids, the individual wind turbines must be able to achieve various power control objectives. In this context, the authors focus their attention on the control of fixed-speed active stall wind turbines. This sort of turbine includes a pitch servomechanism to induce stall on the blades, thereby having control on the output power. The authors develop a methodology to design optimal gain-scheduled pitch controllers valid for the whole operating region of the wind turbine. The proposed solution uses concepts of linear parameter-varying system theory. In addition to providing a formal framework for the control design, this theory guarantees stability and performance. Further, because of the similarities with Hinf control, the tools developed for the controller design are very familiar to the control community. The main features of the proposed controller are assessed by means of numerical simulations obtained for realistic wind speed profiles and power production demands.

}, keywords = {fixed-speed active stall wind turbines, Hinf control, Hinfin control, linear parameter-varying system theory, linear systems, optimal gain-scheduled control, pitch servomechanism, power generation control, power production demands, wind farms, wind speed profiles, wind turbines}, issn = {1752-1416}, doi = {10.1049/iet-rpg:20070106}, url = {http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=4610980\&tag=1}, author = {Bianchi, Fernando D. and De Battista, Hern{\'a}n and Mantz, Ricardo J.} } @article {80, title = {Control of variable-speed wind turbines by LPV gain scheduling}, journal = {Wind Energy}, volume = {7}, year = {2004}, pages = {1{\textendash}8}, abstract = {

This article considers gain-scheduling control of variable-speed wind energy conversion systems (WECS) in the context of linear parameter-varying (LPV) systems. The typical problems of the classic gain-scheduling techniques, such as stability guarantees, undesirable transient responses in the controller commutations and arduous design procedures, can be avoided with this new formulation. A model of a variable-speed WECS expressed in LPV form and an optimal LPV gain-scheduling control strategy are presented.

}, keywords = {gain scheduling, linear parameter-varying systems, wind energy conversion systems, wind turbines}, issn = {1099-1824}, doi = {10.1002/we.103}, url = {http://dx.doi.org/10.1002/we.103}, author = {Bianchi, Fernando D. and Mantz, Ricardo J. and Christiansen, Carlos F.} } @article {63, title = {Dynamical variable structure controller for power regulation of wind energy conversion systems}, journal = {Energy Conversion, IEEE Transactions on}, volume = {19}, year = {2004}, month = {Dec}, pages = {756-763}, abstract = {

The paper addresses the problem of output power regulation of fixed-pitch variable-speed wind energy conversion systems. Operation is constrained by practical reasons to the low-speed side of the turbine power-speed curve. Unfortunately, this region is characterized by a nonminimum phase dynamics which is an obstacle to perform the regulation task. A dynamical variable structure controller is developed that accomplishes the control objective despite this limitation. The proposed control strategy presents attractive features such as robustness to parametric uncertainties of the turbine and generator as well as to electric grid disturbances.

}, keywords = {65, Aerodynamics, Control systems, dynamical variable structure controller, electric grid disturbance, Electric variables control, Induction generators, Mesh generation, nonminimum phase dynamic, parametric uncertainty, Power control, Power generation, power generation control, power regulation, power supply quality, power system dynamic stability, power system interconnection, speed curve, turbine power, variable structure systems, Wind energy, wind energy conversion system, Wind energy generation, wind power, Wind speed, wind turbines}, issn = {0885-8969}, doi = {10.1109/TEC.2004.827705}, url = {http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=1359955}, author = {De Battista, Hern{\'a}n and Mantz, Ricardo J.} } @article {108, title = {Power control of a solar/wind generation system without wind measurement: a passivity/sliding mode approach}, journal = {Energy Conversion, IEEE Transactions on}, volume = {18}, year = {2003}, month = {Dec}, pages = {501-507}, abstract = {

This paper deals with the control of the output power of a solar/wind stand-alone system. The control system regulates the generation of the wind subsystem in order to satisfy, jointly with the photovoltaic generation subsystem, the load and battery charge power demand. The controller is designed using a theoretical framework that unifies passivity and sliding mode techniques. The resultant control law does not need wind measurement and only relies on rotational speed and current measurements. An analysis of the acceleration estimate error is carried out and a countermeasure to compensate its effects is proposed. Finally, the performance of the controller is assessed through computer simulation, using a comprehensive nonlinear model of the plant.

}, keywords = {acceleration estimate error, angular velocity measurement, Battery charge measurement, Computer Simulation, control law, Control systems, controller design, Current measurement, current measurements, effects compensation, electric current measurement, hybrid power systems, nonlinear model, output power control, passivity/sliding mode approach, photovoltaic generation subsystem, photovoltaic power systems, Power control, power demand, Power generation, power generation control, Power measurement, rotational speed measurements, Sliding mode control, sliding mode techniques, Solar power generation, solar/wind generation system, stand-alone system, variable structure systems, Wind energy generation, wind generation subsystem control, Wind power generation, wind turbines}, issn = {0885-8969}, doi = {10.1109/TEC.2003.816602}, url = {http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=1247775}, author = {Valenciaga, Fernando and Puleston, Pablo F. and Battaiotto, Pedro E.} } @article {72, title = {Dynamical sliding mode power control of wind driven induction generators}, journal = {Energy Conversion, IEEE Transactions on}, volume = {15}, year = {2000}, month = {Dec}, pages = {451-457}, abstract = {

This paper concerns power regulation of variable-speed wind energy conversion systems. These systems have two regions of operation, depending on the tip speed ratio of the wind turbines. They are distinguished by a minimum phase behavior in one of these regions and a nonminimum phase one in the other. A sliding mode control strategy is proposed that assures stability in both regions of operation and imposes the ideally designed feedback control solution in spite of model uncertainties. Moreover, power regulation by the proposed sliding control in the minimum phase region is completely robust to wind disturbances and parameter uncertainties

}, keywords = {asynchronous generators, Control systems, dynamical sliding mode power control, feedback, ideally designed feedback control solution, Induction generators, machine control, minimum phase behavior, minimum phase region, model uncertainties, nonminimum phase region, parameter uncertainties, Power control, Power generation, power regulation, Power system modeling, Robustness, Sliding mode control, stability, tip speed ratio, variable speed gear, variable structure systems, variable-speed wind energy conversion systems, wind disturbances, wind driven induction generators, Wind energy, Wind energy generation, Wind power generation, wind turbines}, issn = {0885-8969}, doi = {10.1109/60.900507}, url = {http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=900507}, author = {De Battista, Hern{\'a}n and Mantz, Ricardo J. and Christiansen, Carlos F.} } @article {74, title = {Sliding mode control of wind energy systems with DOIG-power efficiency and torsional dynamics optimization}, journal = {Power Systems, IEEE Transactions on}, volume = {15}, year = {2000}, month = {May}, pages = {728-734}, abstract = {

Wind turbines with double output induction generators can operate at variable speed permitting conversion efficiency maximization over a wide range of wind velocities. However, random wind fluctuations, wind shear and tower shadow, may excite the oscillation mode of the mechanical system, producing large torque ripple. Consequently, damage to drive train components and power quality problems may occur. In this paper, a sliding mode control is developed which provides a suitable compromise between conversion efficiency and torque oscillation smoothing. The resultant sliding dynamics is completely robust to uncertainties in the electrical variables and parameters. In addition, to prevent windup problems due to saturation, a combined sliding surface that incorporates such limitations is proposed

}, keywords = {asynchronous generators, combined sliding surface, conversion efficiency maximization, double output induction generators, drive train components, electrical variables uncertainties, Fluctuations, Induction generators, large torque ripple, machine control, mechanical system, Mechanical systems, oscillation mode excitation, oscillations, Poles and towers, power efficiency, power generation control, Power quality, power quality problems, power supply quality, random wind fluctuations, resultant sliding dynamics, Sliding mode control, Torque, torque oscillation smoothing, torsion, torsional dynamics optimization, tower shadow, uncertainties robustness, variable speed, variable speed gear, variable structure systems, Wind energy, wind energy systems, wind shear, Wind speed, wind turbines}, issn = {0885-8950}, doi = {10.1109/59.867166}, url = {http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=867166}, author = {De Battista, Hern{\'a}n and Puleston, Pablo F. and Mantz, Ricardo J. and Christiansen, Carlos F.} }