Isolated Wind Energy Conversion System Research Articles

Investigations on the Modulation Strategies for Performance Improvement of a Controlled Wind Energy System

The challenges faced in an isolated wind energy conversion system (WECS) are larger transient times, high steady-state error, and larger harmonic content. To overcome these issues, an adaptive voltage controller (AVC) along with the load current observer (LCO) could be the better proposition. However, the AVC and LCO, in conjunction with the conventional space vector pulse width modulation (SVPWM) technique to operate the three-phase inverter of WECS, would not be able to further improve these parameters. This paper proposes the use of the unified voltage SVPWM (UVSVPWM) technique along with the AVC and LCO, which could improve the transient behavior by about 30% as well as reduce the harmonic content of the load voltage and current by about 70% and 2%, respectively. This paper considers an isolated WECS connected to the linear load, which is operated under balanced as well as unbalanced load conditions. The proposed control technique is verified for both the balanced and unbalanced cases using MATLAB/Simulink.

WITHDRAWN: Performance analysis of isolated wind energy conversion system connected to unbalanced loads

The load tension and frequency are impaired when the unbalanced load is unexpectedly attached to the insulated wind energy transformation grid (IWECS). By using the appropriate control and pulse width modulation technologies for the IWECS, the results may be reduced. The controller consists of an Adaptive Tense Controller (AVC) to regulate the overall harmonic distortion (USVPW) and a Unified Space Vector Pulsenwidth (USVPW) modulator for controlling the Inverter output tension and frequency, the Load Current Observer (LCO). This article simulates the IWECS with MATLAB/Simulink and discusses the results of the study with LCO, AVC and combined space vector PWM modulation technology.

Design of Fuzzy Gain Scheduled PI Controller for an Isolated Wind Energy Conversion System

Design of Fuzzy Gain Scheduled PI Controller for an Isolated Wind Energy Conversion System

Voltage Control of Isolated Wind Energy Conversion System using Adaptive Voltage Controller for Non-Linear Loads

Electrical energy demand increases day-by-day due to economic growth, technology development and increasing world population. The wind is one of the accessible renewable energy sources to generate electrical energy to meet the increased load demand. When the wind energy conversion system (WECS) is operating as isolated mode, it is more reliable, economical and easy to electrify rural areas. When the WECS is connected to load without controller the output three-phase voltages of the inverter have more transient and steady state errors and higher total harmonic distortion in the voltages and currents. This paper discusses various voltage controllers used in WECS in detail. The proposed WECS is simulated using MATLAB/Simulink with and without adaptive voltage controller for balanced and unbalanced non-linear load conditions. In each case the results have been analyzed and total harmonic distortion is evaluated..

Robust Fuzzy Neural Network Sliding Mode Control For Wind Turbine with a Permanent Magnet Synchronous Generator

Abstract —In the present paper, we are interested in the contribution of wind power to the electricity supply in power systems of small sized isolated communities. A robust fuzzy neural sliding control (FNSC) is proposed to track the maximum power point for an isolated wind energy conversion system using a permanent magnet synchronous generator (PMSG) with a hysteresis rectifier connected to a DC load. The turbine is controlled by a sliding mode controller (SMC) to reach the maximum power level. The main objective of the control is to adjust the rectifier voltage to provide it to the DC load as well as to maintain the maximum power extraction. In presence of large uncertainties and wind speed variations, the traditional SMC produces the chattering phenomenon due to the higher needed gain. In order to reduce this gain, FNSC is used for the estimation of the unknown part, thus provide lower gain. The stability of the proposed FNSC is analyzed by Lyapunov theory, simulations results are presented and the proposed control performance is shown by the comparison with the conventional SMC.

Application of nonlinear predictive control for charging the battery using wind energy with permanent magnet synchronous generator

Wind energy is an important renewable source which is used for power generation for a stand-alone as well as grid connected applications. In many remote areas, loads are usually connected away from the grid. In such cases, isolated wind energy systems can be considered as an effective way to provide continuous power to electrical loads.In this paper, a robust nonlinear predictive control (NLPC) for an isolated wind energy conversion system is implemented using a variable speed permanent magnet synchronous generator (PMSG) with pulse with modulation (PWM) rectifier connect to a battery. The turbine is employed with Optimal Torque control (OTC) to achieve a maximum level of wind power extraction.The main of control is to adjust the rectifier voltage amplitude in order to charge battery and this despite the presence of disturbance which manifests in the variation of wind speed and load changes varying. This control it has-been experimentally Implemented using Dspace1104 hardware driving in real-time the studied system.Practical and simulation results show that the NLPC imposes the voltage under wind conditions. The controller shows a good performance during dynamic and steady state condition.

Modeling, control and fault diagnosis of an isolated wind energy conversion system with a self-excited induction generator subject to electrical faults

In this paper, a contribution to modeling and fault diagnosis of rotor and stator faults of a Self-Excited Induction Generator (SEIG) in an Isolated Wind Energy Conversion System (IWECS) is proposed. In order to control the speed of the wind turbine, while basing on the linear model of wind turbine system about a specified operating point, a new Fractional-Order Controller (FOC) with a simple and practical design method is proposed. The FOC ensures the stability of the nonlinear system in both healthy and faulty conditions. Furthermore, in order to detect the stator and rotor faults in the squirrel-cage self-excited induction generator, an on-line fault diagnostic technique based on the spectral analysis of stator currents of the squirrel-cage SEIG by a Fast Fourier Transform (FFT) algorithm is used. Additionally, a generalized model of the squirrel-cage SEIG is developed to simulate both the rotor and stator faults taking iron loss, main flux and cross flux saturation into account. The efficiencies of generalized model, control strategy and diagnostic procedure are illustrated with simulation results.

Performance of Voltage and Frequency Controller in Isolated Wind Power Generation for a Three-Phase Four-Wire System

This paper deals with a new control algorithm for a voltage and frequency controller (VFC) of an isolated wind energy conversion system (IWECS) using an isolated asynchronous generator to feed three-phase four-wire consumer loads. The reference source currents are estimated for the indirect current control of a voltage source converter (VSC) using the single-phase PQ theory to control the voltage and frequency of IWECS. A three-leg VSC with a battery energy storage system is used as a VFC for an IWECS. A nonisolated star-polygon transformer is used to provide a neutral terminal for four-wire loads and to compensate the neutral current resulting in reduction in rating of VSC. The proposed VFC is implemented using a DSP. Experimental results are presented to demonstrate the additional capabilities of VFC as a load leveler, a load balancer, a harmonic eliminator, and a neutral current compensator.

Voltage and Frequency Controllers for an Asynchronous Generator-Based Isolated Wind Energy Conversion System

This paper presents a state of art on voltage and frequency controllers (VFCs) for isolated asynchronous generators (IAGs) for standalone wind energy conversion systems. In wind turbine-driven IAG, magnitude and frequency of the generated voltage vary because of varying consumer loads and wide fluctuation in wind speeds. Therefore, new types of VF controllers based on a voltage source converter along with a battery energy storage system are proposed to maintain the voltage and frequency of IAG constant at varying wind speeds and varying consumer loads. A set of new VF controllers is designed and their performance is simulated in the MATLAB environment using Simulink and Sim-Power System toolboxes to study their behavior for standalone wind power generation.

Three-Phase 4-Wire Isolated Wind Energy Conversion System Employing VSC with a T-Connected Transformer for Neutral Current Compensation

This paper presents a voltage and frequency controller (VFC) for a 4-wire stand-alone wind energy conversion system (WECS) employing an asynchronous generator. The proposed VF con-troller consists of a three leg IGBT (Insulated Gate Bipolar Junction Transistor) based voltage source converter and a battery at its DC bus. The neutral terminal for the consumer loads is created using a T-connected transformer, which consists of only two single phase transformers. The control algorithm of the VF controller is developed for the bidirectional flow capability of the active power and reactive power control by which it controls the WECS voltage and frequency under different dynamic conditions, such as varying consumer loads and varying wind speeds. The WECS is modeled and simulated in MATLAB using Simulink and PSB toolboxes. Extensive results are presented to demonstrate the capability of the VF controller as a harmonic eliminator, a load balancer, a neutral current compensator as well as a voltage and frequency controller.