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Various control strategies for power regulation in variable-speed wind turbines commonly assume that the whole system parameters are known and available, which is not necessarily satisfied in practice. In this work, an adaptive control strategy, which neither need to know completely the system parameters nor the rotor acceleration, is proposed for power regulation and tracking. It also includes a...
Darrieus type vertical axis wind turbines are preferred for the small scale distributed power generation for their distinctive advantages, yet these lift based turbines suffers from poor self-starting capability. As a potential solution, a Dual rotor Darrieus Turbine (DD) with secondary rotor in addition to the primary rotor has been proposed to improve the self-starting characteristics and to enhance...
This paper proposes the use of an active yaw system to protect small and medium wind turbines in the high wind zone from overloading. The active yaw system turns the rotor partially out of the wind to decrease the turbine power. The dependency of the power on the yaw angle is modeled by the third power of the cosine of the yaw angle. A proper controller is configured based on on-off control of the...
The goal of this paper is to design a wind turbine generator operated under variable speed with intelligent pitch angle control capability under variable wind conditions. The control scheme for the variable speed wind turbines has been discussed and analysed using wind turbines driven by the permanent magnet generators connected to the grid. Main strategies of conventional control and intelligent...
The paper presents the development of a wind turbine emulator, which consists of an induction motor driven by a torque control inverter, and the dead-beat controller plays an important role in this structure. The wind turbine emulator system includes the dead-beat current controller, wind speed emulator, mathematical model of wind turbines, model of rotor blade characteristics, and model of tower...
The Darrieus wind turbines are simple in design with high power coefficient, yet they are poor performers in low wind speed regime. As a potential solution to improve the low wind speed performance, a notched airfoil (KF-N-21) was incorporated into straight bladed Darrieus rotor and experimentally compared with conventional NACA0021 rotor from the earlier study. The experimental results displays the...
Recent trends in wind turbine design have demonstrated that decreased levelized cost of energy (LCOE) can be achieved by increasing rotor size and therefore the amount of energy a wind turbine can capture. However, as rotor radii increase into extreme scales, it is likely that the increased mass required to maintain the necessary structural strength for three-bladed upwind turbines will drive up costs...
Modern wind turbines are mainly horizontal axis and operate in bottom atmospheric boundary layer driven by wind shear flow, therefore as the blades rotating the aerodynamic load vary cyclically, with horizontal axis wind turbine (HAWT) large-scaling the cyclical characteristic becomes more obvious, shortening blade life and increasing cost of wind turbine. As the development of wind turbine large-scaling...
Pitch angle control system is one of the most diversified and popularly used control techniques to regulate the output power and speed of a wind turbine, when wind speed is above the rated speed. Usually PI controller is used for pitch angle control. But in this paper Proportional-Integral-Derivative (PID) and Fuzzy Logic Control (FLC) methods are used. As our system contains strong non-linearity,...
The mechanical control schemes based on blade pitch angle and the other scheme tip speed ratio in Wind Turbine (WT) operation are required to attain constant power generation. Therefore, it is required to use peculiar and effective controllers to implement and investigate in such a way to attain torque which should be constant. The suitable and effective controlling methodologies are proportional-integral...
This paper proposes a multi-objective optimal control and switching strategy for floating offshore wind turbines when the wind speed can be approximately predicted. The system is modeled as a hybrid automaton with two modes corresponding to the turbine operation in low- and high-speed wind profiles. The main control objective in the low-speed wind mode is to maximize the total captured power in a...
The main challenges in harvesting energy from the wind arise from the unknown incoming turbulent wind field. Balancing the competing interests of reduction in structural loads and increasing energy production is the goal of a wind turbine controller to reduce the cost of producing wind energy. Conventional wind turbines use feedback methods to optimize these goals, reacting to wind disturbances after...
The stochastic nature of wind speed, time-varying of system parameters, system lagging and nonlinearities can lead to instability of the power generated by wind turbines. In order to improve the dynamic performance in the operation region of constant power output, multivariable control strategy using a sliding mode control technique is proposed based on analysis of the pitch-controlled system research...
This paper presents a grid-connected Wind Energy Conversion System (WECS) using a permanent magnet synchronous generator (PMSG) operating with variable speed. A maximum power point tracking (MPPT) algorithm is used to determinate the power to be extracted from the generator for each rotational speed while wind power remains lower than the PSMG rated power. Otherwise, the MPPT algorithm is disabled...
In this paper a two-region power control system of wind turbine generator by aero dynamical torque estimation is presented. It is based on adaptive observer design augmented with an extra integral state. This observer exhibits adaptive features with respect to the external forces applied to the plant (such as aero dynamical torque variation). The simulation results show the control system good efficiency...
This paper aims to design a pitch control system for wind turbine to improve system dynamic performances. As winds turbines are a nonlinear, strong coupling systems, the sliding mode control is the best approach for its control. At first, a simple sliding mode controller has been developed and implemented on the turbine. Then, an improving sliding mode controller has been implemented in order to reduce...
The aim of this paper is to present a maximum power point tracking (MPPT) method for wind power systems. The control algorithm uses Back-stepping Control technique. This control strategy, based on electromagnetic torque, tracks the maximum power for different wind speeds. The control of our system is tested under fault condition by simulation. A few results are presented and discussed to prove simplicity,...
Hydrostatic transmission systems (HTS) have shown potential in replacing gearbox in conventional wind turbines. However, the general perception about these systems is that they suffer from low efficiencies, specifically at low wind speeds. This paper presents a novel technique that can improve the annual energy production (AEP) beyond that of a conventional wind turbine. By optimizing the operating...
This paper presents the modelling and simulation of a wind turbine driven Permanent Magnet Synchronous Generator connected to a load. The system has been tested at different wind speeds. The machine side controller has been designed to match Maximum Power Point Tracking (MPPT) to obtain high extraction of wind power when connected to a load, while the load side controller fixes the DC voltage that...
In order to evaluate the influence of the yaw error on wind farm active output, blade element theory is used on aerodynamic characteristics modeling of horizontal axis wind turbine. This paper is based on the analysis of blade element force. Considering the effects of wind direction error, eddy current and gas compressibility, the model is realized in MATLAB/Simulink. The system model of wind turbine...
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