@article{GauterinPoeschkeSchulte, author = {Gauterin, Eckhard and P{\"o}schke, Florian and Schulte, Horst}, title = {Global Versus Local Lyapunov Approach Used in Disturbance Observer-Based Wind Turbine Control}, series = {Frontiers in Control Engineering}, volume = {3}, journal = {Frontiers in Control Engineering}, publisher = {Frontiers Media S.A.}, issn = {2673-6268}, doi = {10.3389/fcteg.2022.787530}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:523-16716}, pages = {1 -- 23}, abstract = {This contribution presents a Lyapunov-based controller and observer design method to achieve an effective design process for more dedicated closed-loop dynamics, i.e., a maximal flexibility in an observer-based controller design with a large consistency in desired and achieved closed-loop system dynamics is intended. The proposed, pragmatic approach enhances the scope for controller and observer design by using local instead of global Lyapunov functions, beneficial for systems with widely spaced pole locations. Within this contribution, the proposed design approach is applied to the complex control design task of wind turbine control. As the mechanical loads that affect the wind turbine components are very sensitive to the closed-loop system dynamic, a maximum flexibility in the control design is necessary for an appropriate wind turbine controller performance. Therefore, the implication of the local Lyapunov approach for an effective control design in the Takagi-Sugeno framework is discussed based on the sensitivity of the closed-loop pole locations and resulting mechanical loads to a variation of the design parameters.}, subject = {Ljapunov-Methode}, language = {en} } @article{OrtbandtDzienisMatusseketal., author = {Ortbandt, Claudius and Dzienis, Cezary and Matussek, Robert and Schulte, Horst}, title = {Parameter Estimation in Electrical Power Systems Using Prony's Method}, series = {Journal of Physics: Conference Series}, volume = {659}, journal = {Journal of Physics: Conference Series}, number = {1}, publisher = {IOP Publishing}, issn = {1742-6588}, doi = {10.1088/1742-6596/659/1/012013}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:523-15562}, pages = {1 -- 12}, abstract = {This paper presents the basic principle of Prony's method, which is used for determining electrical power system parameters such as phasors, angular speeds as well as damping factors in a large frequency range. For fixed sampling frequencies, the approach to finding an optimal model order and to extracting transient parameters for further identification of different system effects is shown. Furthermore, it is shown that the method can be applied to the diverse plausibility checks for a confirmation of the result obtained using a conventional Fourier based approach. It will be presented that the significant advantage of the Prony algorithm in comparison to Fourier based methods is the possibility of computing an accurate frequency and in determining a damping factor.}, subject = {Prony-Verfahren}, language = {en} } @article{Schulte, author = {Schulte, Horst}, title = {Uncertainty Quantification for Robust Control of Wind Turbines using Sliding Mode Observer}, series = {Journal of Physics: Conference Series}, volume = {753}, journal = {Journal of Physics: Conference Series}, number = {5}, publisher = {IOP Publishing}, issn = {1742-6588}, doi = {10.1088/1742-6596/753/5/052030}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:523-15559}, pages = {1 -- 10}, abstract = {A new quantification method of uncertain models for robust wind turbine control using sliding-mode techniques is presented with the objective to improve active load mitigation. This approach is based on the so-called equivalent output injection signal, which corresponds to the average behavior of the discontinuous switching term, establishing and maintaining a motion on a so-called sliding surface. The injection signal is directly evaluated to obtain estimates of the uncertainty bounds of external disturbances and parameter uncertainties. The applicability of the proposed method is illustrated by the quantification of a four degree-of-freedom model of the NREL 5MW reference turbine containing uncertainties.}, subject = {Windturbine}, language = {en} } @article{WeberJungjohannSchulte, author = {Weber, Wolfgang and Jungjohann, Jonas and Schulte, Horst}, title = {Physically-based modeling of speed sensors for fault diagnosis and fault tolerant control in wind turbines}, volume = {570}, number = {7}, issn = {1742-6596}, doi = {10.1088/1742-6596/570/7/072008}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:523-15547}, abstract = {In this paper, a generic physically-based modeling framework for encoder type speed sensors is derived. The consideration takes into account the nominal fault-free and two most relevant fault cases. The advantage of this approach is a reconstruction of the output waveforms in dependence of the internal physical parameter changes which enables a more accurate diagnosis and identification of faulty incremental encoders i.a. in wind turbines. The objectives are to describe the effect of the tilt and eccentric of the encoder disk on the digital output signals and the influence of the accuracy of the speed measurement in wind turbines. Simulation results show the applicability and effectiveness of the proposed approach.}, subject = {Windturbine}, language = {en} } @article{GeorgHeydeSchulte, author = {Georg, S{\"o}ren and Heyde, Stefan and Schulte, Horst}, title = {Sensor Fault-Tolerant Control of a Drivetrain Test Rig via an Observer-Based Approach within a Wind Turbine Simulation Model}, volume = {570}, number = {8}, issn = {1742-6596}, doi = {10.1088/1742-6596/570/8/082004}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:523-15538}, pages = {1 -- 11}, abstract = {This paper presents the implementation of an observer-based fault reconstruction and fault-tolerant control scheme on a rapid control prototyping system. The observer runs in parallel to a dynamic wind turbine simulation model and a speed controller, where the latter is used to control the shaft speed of a mechanical drivetrain according to the calculated rotor speed obtained from the wind turbine simulation. An incipient offset fault is added on the measured value of one of the two speed sensors and is reconstructed by means of a Takagi-Sugeno sliding-mode observer. The reconstructed fault value is then subtracted from the faulty sensor value to compensate for the fault. The whole experimental set-up corresponds to a sensor-in-the-loop system.}, subject = {Windturbine}, language = {en} } @article{GeorgMuellerSchulte, author = {Georg, S{\"o}ren and M{\"u}ller, Matthias and Schulte, Horst}, title = {Wind Turbine Model and Observer in Takagi-Sugeno Model Structure}, volume = {555}, number = {1}, issn = {1742-6596}, doi = {10.1088/1742-6596/555/1/012042}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:523-15528}, pages = {1 -- 10}, abstract = {Based on a reduced-order, dynamic nonlinear wind turbine model in Takagi- Sugeno (TS) model structure, a TS state observer is designed as a disturbance observer to estimate the unknown effective wind speed. The TS observer model is an exact representation of the underlying nonlinear model, obtained by means of the sector-nonlinearity approach. The observer gain matrices are obtained by means of a linear matrix inequality (LMI) design approach for optimal fuzzy control, where weighting matrices for the individual system states and outputs are included. The observer is tested in simulations with the aero-elastic code FAST for the NREL 5 MW reference turbine, where it shows a stable behaviour in turbulent wind simulations.}, subject = {Windturbine}, language = {en} } @article{SchulteGeorg, author = {Schulte, Horst and Georg, S{\"o}ren}, title = {Nonlinear Control of Wind Turbines with Hydrostatic Transmission Based on Takagi-Sugeno Model}, volume = {524}, number = {1}, issn = {1742-6596}, doi = {10.1088/1742-6596/524/1/012085}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:523-15502}, pages = {1 -- 8}, abstract = {A nonlinear model-based control concept for wind turbines with hydrostatic transmission is proposed. The complete mathematical model of a wind turbine drive train with variable displacement pump and variable displacement motor is presented. The controller design takes into consideration the nonlinearity of the aerodynamic maps and hydrostatic drive train by an convex combination of state space controller with measurable generator speed and hydraulic motor displacement as scheduling parameters. The objectives are the set point control of generator speed and tracking control of the rotor speed to reach the maximum power according to the power curve in the partial-load region.}, subject = {Windturbine}, language = {en} } @article{BernickeGauterinSchulteetal., author = {Bernicke, Olaf and Gauterin, Eckhard and Schulte, Horst and Zajac, Michal}, title = {Control Engineering Analysis of Mechanical Pitch Systems}, volume = {555}, number = {1}, issn = {1742-6596}, doi = {10.1088/1742-6596/555/1/012009}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:523-15516}, pages = {1 -- 10}, abstract = {With the help of a local stability analysis the coefficient range of a discrete damper, used for centrifugal forced, mechanical pitch system of small wind turbines (SWT), is gained for equilibrium points. - By a global stability analysis the gained coefficient range can be validated. An appropriate approach by Takagi-Sugeno is presented in the paper.}, subject = {Windturbine}, language = {en} } @article{GauterinSchulteGeorg, author = {Gauterin, Eckhard and Schulte, Horst and Georg, S{\"o}ren}, title = {Disturbance Compensation by Wind Speed Reconstruction based on a Takagi-Sugeno Wind Turbine Model}, volume = {524}, number = {1}, issn = {1742-6596}, doi = {10.1088/1742-6596/524/1/012072}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:523-15497}, pages = {1 -- 10}, abstract = {In this work, the nonlinear Tagaki-Sugeno modelling method is utilised to set up an observer-based feed-forward control scheme for wind turbines, which can compensate for the influence of the disturbing wind variation on the rotational speed. The applied scheme leads to a reduced thrust force acting on the rotor.}, subject = {Windturbine}, language = {en} } @article{GeorgSchulte, author = {Georg, S{\"o}ren and Schulte, Horst}, title = {Fault-Tolerant Control of Wind Turbines using a Takagi-Sugeno Sliding Mode Observer}, volume = {524}, number = {1}, issn = {1742-6596}, doi = {10.1088/1742-6596/524/1/012053}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:523-15485}, pages = {1 -- 10}, abstract = {In this paper, observer-based fault-tolerant control schemes for actuator and sensor faults are implemented within dynamic wind turbine simulations. The faults are directly reconstructed by means of a Takagi-Sugeno sliding mode observer. As simulation models, both a reduced-order model with 4 degrees of freedom and the aero-elastic code FAST by NREL are used. A fault-tolerant control scheme is set up by subtracting the reconstructed fault from the faulty control signal respectively sensor value. With these fault compensation schemes, the corrected controller behaviour is close to the fault-free case. The global stability of the controller in the full-load region in the presence of faults and with active fault compensation is shown by analysing the derivative of an appropriate Lyapunov function.}, subject = {Windturbine}, language = {en} } @article{GigerKleinhanslSchulte, author = {Giger, Urs and Kleinhansl, Stefan and Schulte, Horst}, title = {Design Study of Multi-Rotor and Multi-Generator Wind Turbine with Lattice Tower—A Mechatronic Approach}, series = {Applied Sciences}, volume = {11}, journal = {Applied Sciences}, number = {22}, editor = {Huang, Wei}, publisher = {MDPI}, issn = {2076-3417}, doi = {10.3390/app112211043}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:523-15279}, pages = {1 -- 14}, abstract = {New locations for onshore technology, which have not been considered so far, must be developed to increase the total installed capacity of renewable energies, especially wind energy. For this purpose, cost-effective wind turbines, even in difficult-to-access locations, such as mountainous and high-mountainous areas, must be designed. This paper presents a novel wind turbine with a related control system that meets these requirements. The proposed turbine uses a multi-rotor configuration with five rotors arranged in a star shape configuration. Each rotor drive train combines up to 12 generators in a maintenance-friendly multi-generator concept. A suitable observer-based control for load mitigation in the full-load region is proposed for the multi-rotor and multi-generator design. Simulations are used to demonstrate the applicability and practical benefits of this concept.}, subject = {Mechatronik}, language = {en} } @article{KlaesPoeschkeSchulte, author = {Klaes, Norbert and P{\"o}schke, Florian and Schulte, Horst}, title = {Grid Forming Stator Flux Control of Doubly-Fed Induction Generator}, series = {Energies}, volume = {14}, journal = {Energies}, number = {20}, editor = {Prieto-Araujo, Eduardo and Ma{\~n}{\´e}, Marc Cheah and Gomis-Bellmunt, Oriol}, publisher = {MDPI}, issn = {1996-1073}, doi = {10.3390/en14206766}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:523-15259}, pages = {1 -- 12}, abstract = {The doubly fed induction generator is widely used in wind power applications. For stand-alone operation of this machine, the control of the stator flux with fixed voltage and frequency has been proposed. This paper extends the stator flux control of the doubly fed induction machine by droop mechanisms, which vary the setpoint of flux magnitude and frequency depending on active and reactive power. This gives the doubly fed induction generator system unknown grid supporting and grid forming performance. The validation of the proposed control scheme has been conducted on a 10kVA testbed system. The closed-loop behavior of the system has been proven to enable grid-tied and islanded operation with the same control structure. The system response to load changes and islanding events show no disruptive transients in both conditions.}, subject = {-}, language = {en} } @article{PoeschkeGauterinKuehnetal., author = {P{\"o}schke, Florian and Gauterin, Eckhard and K{\"u}hn, Martin and Fortmann, Jens and Schulte, Horst}, title = {Load mitigation and power tracking capability for wind turbines using linear matrix inequality-based control design}, series = {Wind Energy}, volume = {23}, journal = {Wind Energy}, number = {9}, publisher = {Wiley}, doi = {10.1002/we.2516}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:523-14498}, pages = {1792 -- 1809}, abstract = {This article deals with nonlinear model-based control design for wind turbines. By systematically integrating several mechanical degrees of freedom in the control design model, the load mitigation potential from the proposed multivariable control framework is demonstrated. The application of the linear matrix inequality (LMI)-based control design is discussed in detail. Apart from the commonly considered power production mode, an extended operating range to provide stabilization of the electrical grid through power tracking is considered. This control functionality allows for an evaluation of the resulting fatigue and ultimate loads for power tracking at different dynamic requirements. The results indicate that under the impact of a dedicated control scheme, this functionality is feasible with respect to the occurring loads and operational behavior of the wind turbine.}, language = {en} } @article{BoualiSchulteMami, author = {Bouali, Chaabane and Schulte, Horst and Mami, Abdelkader}, title = {A High Performance Optimizing Method for Modeling Photovoltaic Cells and Modules Array Based on Discrete Symbiosis Organism Search}, series = {Energies}, volume = {12}, journal = {Energies}, number = {12}, publisher = {MDPI}, issn = {1996-1073}, doi = {10.3390/en12122246}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:523-3920}, pages = {32}, language = {en} }