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The mathematical models of hydraulic braking system were built through studying the braking system of the wind turbine. The AMESim software was used to establish the simulation model of hydraulic braking system and the controller model, which was employed to the coupling of the simulation, constructed in Matlab/Simulink. The designed soft braking system was tested in the wind turbine. The analysis...
A real wind power generation system is given in this paper. SVM control strategy and vector control is applied for generator side converter and doubly fed induction generator respectively. First the mathematical models of the wind turbine rotor, drive train, generator side converter are described. Then the control strategy of generator side converter system is given in detail. Finally the simulation...
This paper proposes a ride-through technique of doubly-fed induction generator (DFIG) wind turbine systems. The control technique uses energy storage devices (ESD) which are controlled with current and power control loops. During grid faults, the generator output power can be reduced by increasing the generator speed, resulting in increased inertial energy of the rotational body. Also, the output...
This dissertation is on control system for MW-class wind turbine. The basic control structure is on the performance of wind turbine and is a control system tracked power curve. To track the power curve, we discuss the control method for variable speed variable pitch that is used for torque control and pitch control. Furthermore, the MW-class wind turbine is a large structure and mechanical load created...
Recently, the size of wind turbines is increased. As a result, the permanent magnet synchronous generator (PMSG) plays an important role because of its simple structure and high efficiency. This paper proposes a torque and pitch control scheme for variable speed wind turbines. A torque controller is designed to maximize the output power below the rated wind speed and a pitch controller is designed...
While the yaw system of the wind turbine operates depending on the wind direction, it makes us acquire the maximum energy and its own mechanical load decreased. Hence, the optimal design of yaw system is extremely important in the design process of the wind turbine. In this study, yaw system is introduced and its efficiency is analyzed by the result of early simulation.
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...
In this paper, a vector control mechanism has been suggested and applied to simulate the operation of a Doubly-Fed Induction Generator (DFIG) attached to an isolated off-the-grid wind turbine, to demonstrate that these generators can be used at lower costs to control the power quality in stand alone wind turbines. In order to achieve this end, the alignment of the d-axis of the synchronously rotating...
This paper proposes an improved current control scheme for the rotor-side converter of a doubly-fed induction generator (DFIG) wind power generation system. The control scheme consists of a proportional (P) controller and a harmonic resonant (R) regulator tuned at the grid frequency. Thus, the positive and negative sequence components of rotor current are fully regulated by the PR controller without...
The objective of this paper is to present a novel five phase fault tolerant doubly salient electromagnetic generator (DSEG) for direct driven wind turbine. The novel generator has same distinct features as follows: first, the generator configuration is simple and reliable. The output voltage is controlled by DC exciting current easily and the position sensors and the active power converters are not...
Renewable energy sources, especially wind turbine generators, are considered as important generation alternatives in electric power systems due to their no exhausted nature and benign environmental effects. Compared to conventional synchronous generator, permanent magnet synchronous generator has many outstanding performances. Due to the technical and economical advantages, low-speed permanent magnet...
With the purpose of improving the operation efficiency of wind power generator, this paper, by analyzing the doubly-fed induction generatorpsilas (DFIG) power characteristic, built up the DFIG active power reference calculation model to achieve the maximal power point tracing (MPPT) and the reactive power reference calculation model to minimize generator loss. The stator flux-linkage oriented vector...
The doubly-fed induction generator (DFIG) based wind turbines of today are often equipped with a crowbar, which can be used to limit the inrush rotor current and protect the ac excitation converter from damage via a set of resistors that are connected to the rotor windings of the DFIG. When the rotor current becomes too high due to the severe grid voltage dips on the transmission line, the crowbar...
This paper presents the analysis and operation of doubly fed induction generator (DFIG)-based wind power generation system under unbalanced network voltage conditions. The limited voltage and current ratings, the control capabilities of both the grid-side and the rotor-side converter (GSC & RSC) for unbalanced network voltage compensation are investigated in detail. A new current control scheme,...
The key technology of variable-speed constant-frequency (VSCF) wind generation is getting the maximum power by adjusting the rotor speed of the induction generator according to the variable wind speed. Wind turbine systems have strong nonlinear multivariable with many uncertain factors and disturbances. Based on the prototype of Wind Electricity Conversion System (WECS), a new Maximum Power Point...
Equivalent circuit parameters of doubly fed induction generator (DFIG) play an important role in the estimation of steady state and dynamic performance of wind turbine system. A new method based on magnetic field finite element analysis is proposed to improve the calculation of the DFIG parameters, especially the inductances. The magnetic field excited by the stator or rotor current is exactly divided...
This paper proposes a novel doubly salient machine. The topology of the machine is described. The flux within the air gap of the novel doubly salient machine is excited by both permanent magnets and field coils. The current of the field coils can be regulated to strengthen or weaken the flux level in the air gap. Therefore, the output voltage of the machine can be controlled easily. The method of...
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...
In order to investigate the impacts of the integration of wind farms into utilities network, it is necessary to analyze the transient performances of wind power generation systems. In this paper, an assessment of the impact that the different representations of drive-train dynamics have on the electrical transient performances of doubly fed induction generator (DFIG) wind turbines with different operationally...
Nowadays, the most widely used variable speed wind turbine type for units above 1 MW is doubly fed induction generator (DFIG). As the wind power penetration continues to increase, wind turbines are required to remain connected during grid faults to ride-through the faults. This paper gives a control oriented modeling of DFIG wind turbines by using causal ordering graph (COG). The control system consists...
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