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The rapid growth rate of wind energy coupled with the increasing sizes of individual wind turbines strengthens the need for optimised wind energy capture. This study utilises the unknown input observer to track the variation of the maximal value of wind turbines’ power coefficient to tune the control law. The proposed observer identifies variations in the power coefficient surface over time due to...
Electrically Controlled Rotor (ECR) is a new concept rotor system which was brought forward at the beginning of the 21st century. A control strategy of the ECR system is given out in this paper. An adaptive blade pitch control strategy of the ECR system is proposed, which is based on the adaptive filter with least mean aquare (LMS) algorithm. A secondary path on-line identification method with random...
This paper presents the design and verification of a model based nonlinear feedforward controller for vertical and horizontal wind disturbance rejection on autonomous helicopters. The feedforward control is based on a helicopter model that is derived using a number of carefully chosen simplifications to make it suitable for the purpose. The model is inverted for the calculation of rotor collective...
In this paper an unknown input observer is designed to detect three different sensor fault scenarios in a specified bench mark model for fault detection and accommodation of wind turbines. A subset of faults is dealt with, which are faults in the rotor and generator speed sensors as well as a converter sensor fault. The proposed scheme detects the speed sensor faults in question within the specified...
Modern wind turbines are capable to work in variable speed operations. These wind turbines are provided with adjustable speed generators, like the double feed induction generator. One of the main advantage of adjustable speed generators is that they improve the system efficiency compared to fixed speed generators because turbine speed is adjusted as a function of wind speed to maximize output power...
This paper presents an RST controller design applied to a horizontal wind turbine, functioning in the above rated wind speeds area. The controller presented here, is a robust digital controller which aims to regulate the wind turbine rotor speed through collective blade pitch control. The paper starts with a state of the art of wind turbines and their problematic and continues with the design of the...
To optimise the performance of the wind generation, wind turbines employ variable speed (VS) variable pitch (VP) control system. Wind turbine is a complex nonlinear mechanical system exposed to uncontrolled wind profiles. Due to this, dynamic and parametric uncertainties arise in the mathematical model of the wind turbines over different operating conditions. This makes the turbine controller design...
A nonlinear model and control of a small-scale helicopter near hovering are investigated. Aiming at the characteristics of the model helicopter, the stabilizer bar dynamics is studied, and the tail rotor with the electronic gyro is discussed in detail. In addition, the main rotor inflow dynamics is modeled basing on the three-state nonlinear Pitt/Peters model. Then, a simplified nonlinear model is...
Different from previous works that require prior trim conditions on the helicopter, this paper proposes a hierarchical PD controller that is robust in controlling untrimmed and therefore critically unstable helicopters. This controller can yield asymptotic stability of the helicopter in horizontal motion control, which can be proven by the linear stability analysis. And this controller can flawlessly...
Scaled-model helicopters are highly nonlinear, coupled, and unstable machines. They have fast response and controlling them is very complicated and need high degree of precision. In this paper, a detailed nonlinear model is derived. Based upon input/output measurements of the nonlinear model, the dynamics of every channel are identified and Linear State Space Models (LSSMs) are obtained. Model Predictive...
This paper presents a helicopter dynamic model controlled by a nonlinear output feedback controller. Particular emphasis is placed on the mathematical modeling of the main rotor dynamics, i.e., modeling the individual dynamics of the blades and the dynamics of the main rotor stabilizing bar. Since the derived model is highly nonlinear, an output feedback controller that uses a nonlinear observer is...
Virtually all quadrotors used in research weigh less than 2 kg, and carry payload measured in hundreds of grams. To be useful platforms for expanded operations, these vehicles must be capable of carrying greater weight. Several obstacles in aerodynamics, design and control must be overcome to enable the construction of larger craft with payloads in excess of 1 kg. We report the key design considerations...
The design of a pitch control capable to respond to frequency deviations is presented in this paper. The pitch control method reserves a percentage of power extracted from the wind turbine in order to help to mitigate frequency deviations when an extra power is needed. For the purpose of pitch control design, the transfer function of the whole system and an adjust of a controller is needed. Results...
Model system based on moment theory, blade element theory and FlightLab software is designed for small-size unmanned helicopter. The system includes three models of helicopter, moment theory model (MTM), blade element theory model (BETM) and FlightLab model (FLM). MTM is used mainly for performance analysis, BETM for control system design and FLM for nonlinear real-time simulation. Then a high-reliable...
Todaypsilas wind power plants use motor driven pitch control for rotor blades as a standard design feature for obtaining optimum efficiency. In harsh environment, such a control element may be critical in case of fault. In order to avoid total damage of the blades an inherently working pitch control design is proposed. It uses the special composite material properties and an advanced design. In addition,...
The wind turbine codes predict wind turbine loads and response in high accuracy and can be used in controller design with the development of the computer technologies. In this paper open source FAST code developed by NREL is studied. The wind turbine controller is designed in the Matlab/Simulink environment and the FAST code is modeled as an S-function. The simulation of the control algorithms with...
Wind power increases rapidly with increase of wind speed. In order to keep wind turbine running even at strong winds wind power capture has to be constrained. Efficient way for constraining wind power capture is the use of pitchable blades. For pitch controller design a suitable wind turbine model is needed. Finding mathematical model that would be a good representation of wind turbine system and...
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