Performance Evaluation of Wind Turbine Driven Squirrel Cage Induction Generator Connected to Grid (original) (raw)
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Energies, 2015
A common problem in wind power plants involves fixed-speed wind turbines. In fact, being equipped with a squirrel-cage induction generator (SCIG), they tend to drain a relevant amount of reactive power from the grid, potentially causing voltage drops and possible voltage instability. To improve SCIG power quality and transient stability, this paper investigates a new control strategy for pitch angle control based on proportional-integral (PI) controller and a fuzzy logic controller (FLC), considering both normal and fault ride-through (FRT) schemes. In the literature, often, the mechanical torque output is assumed constant for a specific wind speed. This might not be accurate, because the mechanical torque-speed typical of a wind turbine depends also on the power coefficient or pitch angle. In this paper, an analytic model of transient stability is proposed using the equivalent circuit of the SCIG and using the concepts of stable and unstable electrical-mechanical equilibrium. The method has been evaluated by comparing the results obtained by the analytic method with the dynamic simulation. The results show that the proposed hybrid controller is effective at smoothing the output power and complying with FRT requirements for SCIG in the power system. Energies 2015, 8 6329
Hybrid Fuzzy Logic Controller for Improving Voltage Stability of Grid Connected SCIG Wind Turbine
Depleting in the fossil fuel and increasing the demand of renewable energy sources have forced researchers to study the concept nonconventional energy sources and explore the best potentials associated with it. Wind turbine and micro hydro turbine with induction generator are considered as alternative choice for fossil fuel depletion. Fixed speed wind turbine is common problem in wind power plants. In fact, being equipped with a squirrel-cage induction generator (SCIG), they tend to drain a relevant amount of reactive power from the grid, potentially causing voltage drops and voltage instability. Wind turbines with isolated mode and with grid connected mode induction generator are being used to generate electrical energy. Grid conneted induction generator found more application as it requires no external excitation. However wind turbine being equipped with SCIG draw large transient currents, sometimes more than machine rated current when it is connected to utility grid. This condition affects on power system when voltage fluctuations occurs thus the continuity of power generation suddenly decreases. Disturbance may be due to fault condition or due to utility grid. To improve SCIG transient stability, this paper investigates a new control strategy for pitch angle control based on proportional-integral (PI) controller and a fuzzy logic controller (FLC). This paper focuses mainly on comparative analysis of hybrid fuzzy logic controller and PI controller which helps to improve transient stability of grid connected SCIG wind turbine. 3 MW wind turbine model developed and simulation results are implemented here through MATLAB software.
PI & Fuzzy Logic Based Controllers STATCOM for Grid Connected Wind Generator
When integrated to the power system, large wind farms pose stability and control issues. A thorough study is needed to identify the potential problems and to develop measures to mitigate them. Although integration of high levels of wind power into an existing transmission system does not require a major redesign, it necessitates additional control and compensating equipment to enable recovery from severe system disturbances. In this paper the STATCOM control scheme for the grid connected wind energy generation system for power quality improvement is simulated using MATLAB/SIMULINK in power systems block set. Fuzzy based controller is designed to improve the source current in STATCOM. A marked reduction in the Total Harmonic Distortion is observed in source current of Wind Power Generation System (WPGS) with the incorporation of Fuzzy controller.
Fuzzy PI controller for wind Energy conversion system
2012
A Wind Energy Conversion System (WECS) differs from a conventional power system. The power output of conventional system can be controlled where as power output of a WECS depends on the wind. This paper describes fuzzy logic control of induction generator speed in wind turbine application. The aim of fuzzy controller is to established maximum power delivery to the grid from available wind power. Fully-controlled wind turbine which consists of induction generator and back-to-back converter is under estimate. This configuration has full control over the electrical torque, full control of the speed, and also supports reactive power compensation and operation under grid disturbances. Fuzzy logic control algorithm has been applied and validated by detailed simulation in MATLAB/Simulink. All system components have been described in detail. All power system components are simulated in MATLAB software for fuzzy control. For studying the performance of controller ,different abnormal condition are applied even the worst case .simulation result can prove the excellent performance of fuzzy control as improving power quality and stability of wind turbine.
2010
In this paper a line excited cage generator is considered which is connected with the grid through a bidirectional PWM converter-inverter system. The generator is controlled by indirect field oriented control (IFOC) scheme. Fuzzy logic controllers (FLC) are used for the control purpose. The first FLC is used in the outer speed loop to track the generator speed with the reference speed for maximum power extraction and the second and third FLCs are used in the inner current loops for control of active and reactive power. The FLCs use normalized values of error and change of error as their inputs. The outputs of the FLCs are again multiplied with gains to give the control signals. A trapezoidal membership function is taken for the error input and triangular membership functions are taken for change of error as well as output. Again a robust self tuned fuzzy logic controller (STFLC) scheme is used in place of the FLCs. In this scheme a tuning FLC (TFLC) is used to tune the output gain o...
Stabilization of a Wind Energy System Using STATCOM Based Fuzzy Logic Controller
17th International Middle-East Power Systems Conference (MEPCON'15), 2015
Nowadays, wind energy system (WES) is the most applicable solution for providing clean energy to the consumers. There is no guarantee for delivering high quality power into the grid. The Flexible AC Transmission Systems (FACTS) devices can be used for ensuring power quality and voltage stability of the WES. This paper presents the application of STATCOM controlled by fuzzy logic (FLC) approach for improving the dynamic performance of the WES connected to the utility grid. To investigate the feasibility of the proposed approach, a three-phase to ground short circuit fault is considered for 80 m. sec. in different locations of the network. Also the duration fault is increased to indicate their effect on the system response. The STATCOM based proportional plus integral (PI) controller is applied for a comparative study with the STATCOM based FLC. The overall system was simulated using MATLAB/Simulink. The simulation results indicates the effectiveness of the proposed STATCOM based FLC over the STATCOM based PI controller.
Fuzzy based STATCOM for Reactive Power Compensation in Grid Connected Wind Farm
In modern electrical distribution systems harmonic distortions are created from a number of sources such as variable frequency drives, lighting, computers and nonlinear loads. Such harmonic distortions produce a variety of undesirable side effects ranging from poor power factor, motor failure to overloading of transformers and conductors. Now a days increasing number of renewable energy systems such as solar and wind turbine generators are connected to the existing power system in order to reduce the negative environmental impact of fossil fuel based conventional electric power generation schemes. But power quality of an electric grid is affected by the penetration of intermittent wind power into it. This paper analyses the harmonic distortion problem, which arises due to the integration of fixed speed induction generator based wind energy
Fuzzy logic control of wind energy conversion system
J. Renewable Sustainable Energy, 2013
This paper proposes a variable speed control scheme of grid-connected wind energy conversion system, WECS, using permanent magnet synchronous generator. The control algorithm tracking the maximum power for wind speeds below rated speed of wind turbines (WTs) and ensure the power will not exceed the rated power for wind speeds higher than the rated speed of wind turbine. The control algorithm employed fuzzy logic controller (FLC) to effectively do this job. The WT is connected to the grid via back-to-back pulse width modulationvoltage source converter (PWM-VSC). Two effective computer simulation software packages (PSIM and SIMULINK) have been used to carry out the simulation effectively where PSIM contains the power circuit of the WECS and MATLAB/SIMULINK contains the control circuit of the system. The control system has two controllers for generator side and grid side converters. The main function of the generator side controller is to track the maximum power from wind through controlling the rotational speed of the turbine using FLC. In the grid side converter, active and reactive power control has been achieved by controlling d-axis and q-axis current components, respectively. V C 2013 American Institute of Physics. [http://dx.
2012
In this paper, a design fuzzy logic controller for a variable speed permanent magnet wind generator connected to a grid system through a LC-filter is proposed. A new current control method of grid side conversion is developed by integrating the fuzzy controller, in which both active and reactive power, delivered to a power grid system, is controlled effectively. The fuzzy logic controller is designed to adjust the gain parameters of the PI controllers under any operating conditions, so that the dynamic stability is enhanced. A new simple method, based on frequency response of the bode diagram, is proposed in the design of the fuzzy logic controller. To evaluate the controller system capabilities, simulation analyses are performed on a small wind farm model system including an induction wind generator connected to an infinite bus. The simulations have been performed using PSCAD/EMTDC. Simulation results show that the proposed control scheme is more effective for enhancing the stability of wind farms during temporary and permanent network disturbances and randomly fluctuating wind speed, compared with that of a conventional PI controller.
STATCOM Controller Design and Experimental Investigation for Wind Generation System
IEEE Access
Controlling of Wind Generation System (WGS) is a vital process to adjust the value of voltage fluctuation that linked to the grid under variations of wind speed. In this paper, a variable speed wind-turbine unit coupled with permanent-magnet synchronous generator is modeled. STATCOM-control methodologies are established on the basis of two controllers; PI controller and Self-Tuning Fuzzy Logic PI-Controller (STFPC). Laboratory model of the WGS using DC motor with an armature current control is designed to achieve a real time simulation of the system. The results are evidenced on the validation of the suggested controlling methodologies. The paper presents experimental comparisons of STFPC with PIcontroller. Also, the superiority of utilizing STFPC over PI-controller has been proven.