720 research outputs found

    Modeling and Control of Power Converter for Doubly Fed Induction Generator Wind Turbines using Soft Computing Techniques

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    This paper is based on Fuzzy Logic Controller (FLC) Control of Doubly Fed Induction Generator (DFIG) wind turbine in a power system for nonlinear loads. By which the nonlinear system can be made to work as a linear system to bring out better performance. . Fuzzy logic is a logical system which provides definite solution to solve problems. It process with fuzzy variables which are defined by membership functions. The combined action of PI and FLC controls the switching actions, distortion in harmonics and provide compensation for unbalanced load if any at the point of common coupling. The proposed system consists of back to back connected converters, one is connected to the generator side and the other is connected to the grid side. The grid side connected converter is used for compensation ie, it act as an Active Power Filter (APF) and compensator hence the cost of using APF is reduced. Reduced Total Harmonic Distortion (THD) is obtained by simulating (MATLAB/SIMULINK) the performance and the result is found to be quite satisfactory. Key Words: Fuzzy Logic Controller, Harmonic Reduction, Power converter, Renewable Energy

    Power Quality Improvement and Low Voltage Ride through Capability in Hybrid Wind-PV Farms Grid-Connected Using Dynamic Voltage Restorer

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    © 2018 IEEE. Translations and content mining are permitted for academic research only. Personal use is also permitted, but republication/redistribution requires IEEE permission.This paper proposes the application of a dynamic voltage restorer (DVR) to enhance the power quality and improve the low voltage ride through (LVRT) capability of a three-phase medium-voltage network connected to a hybrid distribution generation system. In this system, the photovoltaic (PV) plant and the wind turbine generator (WTG) are connected to the same point of common coupling (PCC) with a sensitive load. The WTG consists of a DFIG generator connected to the network via a step-up transformer. The PV system is connected to the PCC via a two-stage energy conversion (dc-dc converter and dc-ac inverter). This topology allows, first, the extraction of maximum power based on the incremental inductance technique. Second, it allows the connection of the PV system to the public grid through a step-up transformer. In addition, the DVR based on fuzzy logic controller is connected to the same PCC. Different fault condition scenarios are tested for improving the efficiency and the quality of the power supply and compliance with the requirements of the LVRT grid code. The results of the LVRT capability, voltage stability, active power, reactive power, injected current, and dc link voltage, speed of turbine, and power factor at the PCC are presented with and without the contribution of the DVR system.Peer reviewe

    A New Converter Station Topology to Improve the Overall Performance of a Doubly Fed Induction Generator-Based Wind Energy Conversion System

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    This thesis presents a reliable and cost effective technique that calls for reconfiguration of the existing converters of a typical Doubly Fed Induction Generator to include a coil of low internal resistance. A coil within the DC link is the only hardware component required to implement this technique. With a proper control scheme, activated during fault conditions, this coil can provide the same degree of performance as a superconducting magnetic energy storage unit during fault conditions

    Artificial Intelligence-Based Fault Tolerant Control Strategy in Wind Turbine Systems

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    This is an Open Access article published by ILHAMI COLAK. Content in the UH Research Archive is made available for personal research, educational, and non-commercial purposes only. Unless otherwise stated, all content is protected by copyright, and in the absence of an open license, permissions for further re-use should be sought from the publisher, the author, or other copyright holder.Power converters play an important role as an enabling technology in the electric power industry, especially in Wind Energy Systems (WESs). Where they ensure to regulate the exchanging powers between the system and the grid. Therefore; any fault occurs in any parts of these converters for a limited time without eliminating, it may degrade the system stability and performance. This paper presents a new artificial intelligence-based detection method of open switch faults in power converters connecting doubly-fed induction (DFIG) generator wind turbine systems to the grid. The detection method combines a simple Fault Tolerant Control (FTC) strategy with fuzzy logic and uses rotor current average values to detect the faulty switch in a very short period of time. In addition, following a power switch failure, the FTC strategy activates the redundant leg and restores the operation of the converter. In order to improve the performance of the closed-loop system during transients and faulty conditions, current control is based on a PI (proportional-integral) controller optimized using genetic algorithms. The simulation model was developed in Matlab/Simulink environment and the simulation results demonstrate the effectiveness of the proposed FTC method and closed-loop current control schemePeer reviewe

    Modeling of FUZZY Controlled UPFC for LVRT Improvement in DFIG Based Grid Connected Wind Farm

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    At present, wind energy generation, usage and its grid infusion is extended in and around the globe. In any case, wind generation is fluctuating a result of time changing nature and causes reliability issues. Wind control fluctuation and network stack changes make disrupting impacts in the PCC voltage. Moreover, Factor speed wind turbine generators foundation has been basically extended worldwide over the latest couple of years. Regardless, issues at the cross section side may require the partition of the wind turbine from the network under such events. Wind Turbine Generator (WTG) may not fit in with the progressing made cross section codes for Wind Energy Change Frameworks (WECS). Doubly Bolstered Enlistment Generator (DFIG) is considered for the variable speed wind farms. The joining of wind turbine into the network makes number of power quality issues. The proposed network generation Low Voltage Ride Through (LVRT) limit of DFIG and it is enhanced by techniques for using Actualities gadgets. Certain devices are used to control the power stream, to extend as far as possible and to enhance the security of the power matrix. A champion among the most comprehensively used Realities contraption is Brought together Power Stream Controller (UPFC). It contains shunt and plan controllers which are related with a DC interface capacitor. By and by methodology for UPFC to improve the LVRT capacity of a DFIG-based breeze ranch voltage list by using Fuzzy Logic Controller (FLC) has been talked about. Thusly the UPFC can satisfactorily improve the LVRT limit of DFIG-based breeze develop, keeping up the breeze turbine to be related with the network amid blame condition. Recreation is finished by using MATLAB/Simulink Instrument

    Application of SMES unit to improve DFIG power dispatch and dynamic performance during intermittent misfire and fire-through faults

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    The number of wind turbines connected to power grids has significantly increased during the last decade. This is mainly due to the convincing revolution in power electronic technology and the growing concern about greenhouse effect that is intensified due to the burning of fossil fuels. Variable speed wind energy conversion systems (WECS) such as doubly fed induction generators (DFIG) are dominating the wind energy market due to their superior advantages over fixed speed-based WECS that include more captured energy, less mechanical stress and acoustical noise. DFIG is interfaced to the ac network through grid side voltage source converter (GSC) and rotor side voltage source converter (RSC) to enable the variable speed operation of the wind turbine and to provide reactive power support to the ac grid during disturbance events. Converter switching malfunction such as misfire and fire-through may influence the power dispatch capability of the DFIG. In this paper, a super conducting magnetic energy storage (SMES) unit is utilized to improve the power dispatch and dynamic performance of DFIG-based WECS during internal converter switching malfunctions such as misfire and fire-through faults. Simulation results without and with SMES connected to the system are presented, compared and analyzed

    Improved control strategy of DFIG-based wind turbines using direct torque and direct power control techniques

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    This paper presents different control strategies for a variable-speed wind energy conversion system (WECS), based on a doubly fed induction generator. Direct Torque Control (DTC) with Space-Vector Modulation is used on the rotor side converter. This control method is known to reduce the fluctuations of the torque and flux at low speeds in contrast to the classical DTC, where the frequency of switching is uncontrollable. The reference for torque is obtained from the maximum power point tracking technique of the wind turbine. For the grid-side converter, a fuzzy direct power control is proposed for the control of the instantaneous active and reactive power. Simulation results of the WECS are presented to compare the performance of the proposed and classical control approaches.Peer reviewedFinal Accepted Versio

    A Novel Inter Connection of DFIG with Grid in Separate Excitation SMES System with Fuzzy Logic Control

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    The use of doubly fed induction generators (DFIGs) in wind turbines has become quite common over the last few years. DFIG wind turbine is an integrated part of distributed generation system. This paper presents a Fuzzy based controller SMES unit in DFIG for improving the ac output on grid side. The excitation system is composed of the rotor-side converter, the grid-side converter, the dc chopper and the superconducting magnet. The superconducting magnet is connected with the dc side of the two converters, which can handle the active power transfer with the rotor of DFIG and the power grid independently, even thou Sutton small fluctuations are occur in active power on AC side. For smoothening the AC output power waveform a Fuzzy based controller is introduced in SMES controller unit, which implemented using simulation developed in MATLAB/ SIMULINK 7.2 version. The model of the FUZZY controlled SMES based excitation system for DFIG is established, and the simulation tests are performed to evaluate the system performance
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