The generator power output is 5000 W and speed is 3600 rpm. The power control setting of Double-Fed In- duction Generator is 5000 W for real power and 200 VAR for reactive power, speed is 3420 rpm (s = 0.05). From the above simulation results, the vector control of a high efficiency Double-FedInductionGenerator and the magnetic field of the stator is fixed on the vertical axis. The real power and reactive power components of the output only related to the relative strengths of the current of cross axis and the vertical axis of the rotor. The gen- erator can operate at lower than synchronous speed, which does not limit to operate at over the synchronous speed. At over synchronous speeds, the stator and rotor produce power; therefore, the output is higher than the rated power and has an excellent characteristic of voltage
_____________________________________________________________________________________________________ Abstract - This paper describes the basic performance of a wind power system based on inductiongenerator. The induction machine which is taken for the purpose of study is the doubly fedinductiongenerator (DFIG). The techniques of direct grid integration, independent power control, and the droop phenomenon of distribution line are studied for DFIG systems. System is modelled in MAT lab/Simulink environment and results are observed for various wind speeds of the turbine.
Meeting grid code requirement creates an obligation to smart WTs disconnection following some electrical or mechanical events. Increasing the penetration level of wind turbines (WTs) in different voltage levels of the network have a major effect on this condition. In this regard, soft and rapid synchronization control of doubly fedinductiongenerator (DFIG) to reduce the dynamic and transient effects of DFIG on a smart grid is very important. This paper gives a review on WTs power generation and a basic requirement to operate in a stable manner in connection to the network at first. After that, different startup and synchronization methods will be described. Then, a new synchronization method for grid connection of DFIG driven by WT is proposed. In this method, the rotor side converter is synchronized with the induced voltage at the rotor winding of DFIG while the stator windings have been connected to the grid and the rotor accelerates normally with the wind torque. This startup process is soft and the synchronization is carried out between two low voltages
Abstract— This work deals with the vector control of the active and reactive powers of a double-fedinductiongenerator (DFIG) for wind energy conversion systems (WECS) by the polynomial RST controller. The control of the statoric power transfer between the machine and the grid is achieved by acting on the rotor parameters and control is provided by the polynomial RST controller. The performance and robustness of the controller are compared with PI controller and evaluated by simulation results in MATLAB/simulink.
This paper presents the performance analysis of two-layer constant-power control (CPC) scheme for a wind farm equipped with doubly fedinductiongenerator (DFIG) wind turbines, where each WTG is equipped with a super capacitor energy storage system (ESS). To meet the requirements of frequency and active power regulation, energy storage devices will be required to dynamically match the intermittency of wind energy. In the two layer control, there is a high layer controller known as Wind farm supervisory control (WFSC), which generates Active power (P), Stator power (Ps), Energy storage power (Pe), DC voltage (Vdc) etc. references for the low layer Wind turbine generator (WTG) controllers, according to the power demand from the grid operator. The low layer wind turbine generator(WTG) controller consist of Rotor side converter control and Grid side converter control to regulate each Doublefedinductiongenerator (DFIG) wind turbine, to generate desired amount of active power, Where the deviations between the available wind energy input and desired active power output are compensated by Super capacitor Energy storage system. Simulation are carried out in MATLAB on a wind farm equipped with multiple DFIG wind turbines to verify the effectiveness of the proposed control scheme.
The global electrical energy consumption is rising and there is a sudden increase in the demand of power generation. Large number of renewable energy units is now being integrated to power system for meeting and the rising demand of power generation. Slip ring induction machine in the variable speed wind turbine popularly known as doublefedinductiongenerator is mostly used in wind power generation. The main reason for the popularity of the doubly fed wind induction generators connected to the power network is their ability to supply power at constant voltage and frequency. Doubly FedInduction generators are used commonly in wind generation purpose. When the slip of the induction motor is negative then it becomes InductionGenerator. For a given speed by controlling the rotor voltage and phase angle the control of real and reactive power is obtained. This paper explains simulation study for d-q axis modeling of a DFIG for steady state and transient conditions. The simulation of wind electric generator system including wind turbine, the DFIG connected to a power system along with other wind mills will be simulated. MATLAB platform is used for Doubly FedInductionGenerator modeling.
Abstract— Wind power generation is increasing rapidly in India and wind integration with the grid is considered as a promising source of energy, DoubleFedInductionGenerator (DFIG) being the most commonly used wind turbine generator, when integrated with the grid show challenges during grid faults. This paper focuses on the challenges faced by DFIG during the occurrence of voltage sags and the Low Voltage Ride Through (LVRT) methods to overcome it. The crowbar protection method is used to ride through voltage sags and FACTS device STATCOM is used to quickly sense the voltage sag and overcome it. Furthermore, simulation has done using MATLAB/ SIMULINK; analyses the performance of combined crowbar protection and STATCOM on DFIG during voltage sags. The results shows that crowbar protection method is a reliable method to ride through the fault and STATCOM helps to sense and overcome voltage sags quickly. Moreover, the grid code requirements are met.
The double-fed asynchronous generator with a vectorial control is a machine that has excellent performance and is commonly used in wind turbine industry. There are many reasons for the use of a double-fedinductiongenerator for a variable speed wind turbine; for instance, the reduction of efforts on the mechanical parts, the reduction of noise and the ability to control the active and reactive power. The wind system which uses DGIF and a "back-to-back" converter that connects the rotor generator to the grid has many advantages. An advantage of this structure is that the used power converters are designed to flow a fraction of the total power of the system [1-3]. The performances of this system depend not only on the DFIG, but also on how the "back-to-back" converter is controlled. While the rotor side converter controls the active and reactive power produced by the generator, the grid side converter allows us to control the DC bus voltage and the power factor of the grid side.
 Satish Choudhury, Kanungo Barada Mohanty, B. Chitti Babu, “Performance Analysis of Doubly fedInductionGenerator For Wind Energy Conversion System” The 5th PSU-UNS International Conference on Engineering and Technology (ICET-2011), Phuket, pp. 532-536, 2-3 May 2011  Huaqiang ZHANG, Zhixin WANG, “Study on Modeling and Simulation of Double-FedInduction Wind Power Generator Control System”, International Conference on Sustainable Power Generation and Supply, pp. 1-5, 6-7 April 2009.
The rotor side converter control system and the grid side converter control system of the above system uses PI controllers. The dynamic behavior of the above system for different faults such as line to ground fault, line to line fault, double line to ground fault and symmetric fault are studied and the graphs of the generated, real power, reactive power and the wind speed are presented in the figure. The PI controllers of the above system are replaced by fuzzy logic controller.
BDFIG has three modes of operation namely simple induction mode, cascaded induction mode and synchronous mode. In the Synchronous Mode of operation of BDFIG is similar to that of a synchronous machine in that (in the ideal case) the phase of the control winding voltage controls the torque of the machine and the magnitude of this voltage controls the reactive power flow in the machine. However, by adjusting the control winding frequency this synchronous machine like performance can be achieved at any speed. The ability to operate in the synchronous mode distinguishes the BDFIG from induction motor drives. The synchronous mode of operation occurs when the double stator windings carries the rotor current of the same frequency. A wind-turbine generator must be fully controllable so that it can operate
Increased penetration of wind energy systems has serious concerns on power system stability. In spite of several advantages, doubly fedinductiongenerator (DFIG) based wind energy systems are very sensitive to grid disturbances. DFIG system with conventional vector control is not robust to disturbances as it is based on PI controllers. The objective of this paper is to design a new vector control that is robust to external disturbances. To achieve this, inner current loop of the conventional vector control is replaced with sliding mode control. In order to avoid chattering effect and achieve finite time convergence, the control gains are selected based on positive semi-definite barrier function. The proposed barrier function adaptive sliding mode (BFASMC) is evaluated by testing it on a benchmark multi-machine power system model under various operating conditions. The simulated results show that the proposed method is robust to various disturbances.
Now-a-days, the consumption of conventional power assets has multiplied, So efforts were made togenerate power from renewable power sources including wind, solar and so forth., Wind strength has emerge as certainly one of themost important and promising assets of renewable strength. This needs extra transmission capability andbetter approach of preserving system reliability. these days the wind electricity potential of the arena is approximately50GW and it's far expected to attain 160GW by using 2012. In current Wind Turbine technology system (WTGS), thewind generators are subjected to version of load and effect of sudden wind pace variations.With accelerated penetration of wind strength into electric grids, Doubly-FedInductionGenerator (DFIG) windturbines are largely
A new configuration for power control system of the doubly-fed wound rotor inductiongenerator is presented. The active and reactive power of generator can be controlled independently and stably. A VPI-based DPC strategy for a wind turbine driven DFIG system under the harmonically distorted grid voltage, ideal grid voltage and transient performance which suppress the power pulsation component, it is implement with smooth active and reactive power output of DFIG under the harmonic voltage. There are four configurations are presented for calculation stator voltage and current as well as rotor current, active power and reactive power of DFIG.
ABSTRACT : This Article studies the V/f control configuration of a Photovoltaic pumping system. The solar generator delivers a direct continuous voltage, that is been inverted into an alternative one by mean of a PWM implemented strategy on the converter. The V/f strategy is studied into two phases, an open loop control and a closed loop one. The paper highlights the technique of keeping constant the V/f ratio, while the machine’s speed is in variation. Thus, insuring to keep constant the maximum torque and the flux of the induction motor.
 M.V.A. Nunes, H.H. Zurn, U.H. Bezerra, J.A. Peças Lopes, R.G.Almeida, "Influence of the Variable Speed Wind Generators in Transient Stability Margin of the Conventional Generators Integrated in Electrical Grids," IEEE Transactions on Energy Conversion. vol.19(4), pp.692-701. 2004.  João P. A. Vieira, Marcus N. A. Nunes, and Ubiratan H. Bezerra, “Design of Optimal PI Controllers for Doubly FedInduction Generators in Wind Turbines Using Genetic Algorithm” IEEE 2008.
Variable speed operation is essential for large wind turbines in order to optimize the energy capture under variable wind speed conditions. Variable speed wind turbines require a power electronic interface converter to permit connection with the grid. The power electronics can be either partially-rated or fully-rated. A popular interface method for large wind turbines that is based on a partially rated interface is the doubly-fedinductiongenerator system. In the DFIG system, the power electronic interface controls the rotor currents in order to control the electrical torque and thus the rotational speed. Because the power electronics only process the rotor power, which is typically less than 25% of the overall output power, the DFIG offers the advantages of speed control for a reduction in cost and power losses. The purpose of grid side converter is to maintain capacitor voltage constant.
Due to continuous increase in power demand we can not depend on limited conventional sources so we go for the renewable energysources in which wind energy has proven technology. Among the different variable speed wind turbine doubly fedinductiongenerator(DFIG) is the commonly used wind turbine in growing wind market. DFIG is usually used to satisfy grid code requirements such as power quality improvement, grid stability,grid synchronization, power control andfault ride through in grid connected wind energy conversion system. To fulfill these requirements DFIG needs a control strategy for both stator and rotor side along with variable frequency power electronic converters (VFC).
The development of wind turbines for electricity generation in 1973 is due to the sudden increase in oil prices and limited fossil resources [1-3]. During that time, a number of programs for research and technological development in USA, UK, Germany and Sweden have been initiated. Through the programs financed by the government, two generator concepts for wind turbines were introduced, namely fixed speed and variable speed generator systems [4-6]. The variable speed generator system is the preferred design for large wind turbines, providing more efficient utilization of power and the ability to reduce the mechanical stress on the system under changing wind conditions [7-9]. There are two types of variable-speed generator used in large wind power plant: synchronous generator with full power converter and DFIG. About two-thirds of the wind turbines are operated with a DFIG, while about a third of them are operated with a high pole synchronous generator . The DFIG has many advantages compared to the synchronous generator includes wider speed range, lower cost of power electronic and better efficiency [10, 13]. In this paper, modeling and simulation of DFIG is performed in order to analyze the behavior of the system. The behavior of DFIG is described in mathematical equations and followed by modeling in the form of block diagrams and simulation using MATLAB/Simulink [11, 12]. Field orientation principle is applied to mimic the behavior of DFIG. The structure of a field-oriented drive with current injection and DFIG consists of several models such as voltage model, current controller and flux observer including coordinate transformation blocks (stator-related (α, β), rotor-related (d, q), and flux-related (m, l) coordinate system) .