101 research outputs found
Distribution Network Voltage Unbalance Control under High Penetration of Single-Phase Photovoltaic Microgeneration
Youcef Bot, Ahmed Allali, Mouloud Denai, ‘Distribution Network Voltage Unbalance Control under High Penetration of Single-Phase Photovoltaic Microgeneration’, paper presented at the 1st EAI International Conference on Smart Grid Inspired Future Technologies, Liverpool, UK, 19-20 May, 2016.Electricity distribution networks are now faced with increasing penetration level of small-scale decentralized renewable energy generation. Meanwhile, distribution network operators are concerned with adverse impacts such as voltage rise and three-phase voltage unbalance that would result. This paper focuses on single-phase solar photovoltaic (PV) integration voltage unbalance issues and proposes a local voltage control strategy for a low voltage (LV) distribution network. The proposed control method is based on real-time management of the active and reactive powers. Simulation results show that the proposed algorithm maintains the quality and reliability of the three-phase voltage in the network and hence provides a potential solution to the challenges facing future distribution networks.Peer reviewedFinal Accepted Versio
Power Quality Enhancement in Electricity Grids with Wind Energy Using Multicell Converters and Energy Storage
In recent years, the wind power industry is experiencing a rapid growth and more wind farms with larger size wind turbines are being connected to the power system. While this contributes to the overall security of electricity supply, large-scale deployment of wind energy into the grid also presents many technical challenges. Most of these challenges are one way or another, related to the variability and intermittent nature of wind and affect the power quality of the distribution grid. Power quality relates to factors that cause variations in the voltage level and frequency as well as distortion in the voltage and current waveforms due to wind variability which produces both harmonics and inter-harmonics. The main motivation behind work is to propose a new topology of the static AC/DC/AC multicell converter to improve the power quality in grid-connected wind energy conversion systems. Serial switching cells have the ability to achieve a high power with lower-size components and improve the voltage waveforms at the input and output of the converter by increasing the number of cells. Furthermore, a battery energy storage system is included and a power management strategy is designed to ensure the continuity of power supply and consequently the autonomy of the proposed system. The simulation results are presented for a 149.2 kW wind turbine induction generator system and the results obtained demonstrate the reduced harmonics, improved transient response, and reference tracking of the voltage output of the wind energy conversion system.Peer reviewedFinal Accepted Versio
Power fuzzy adaptive control for wind turbine
In recent years, wind energy has become one of the most promising renewable energy sources. The doubly-fed induction generator (DFIG) is currently the most common type of generator used in wind farms. This paper describes an approach for the independent control of the active and reactive power of the variable-speed DFIG. This paper deals with the control of the active and reactive powers in a DFIG designed for a wind system. The simulation model including a 7 KW - DFIG driven by a wind turbine, a PWM inverter and the proposed control strategy are developed and implemented using Matlab Simulink
Numerical simulations of heat explosion with convection in porous media
International audienceIn this article, we study the interaction between natural convection and heat explosion in porous media. The model consists of the heat equation with a nonlinear source term describing heat production due to an exothermic chemical reaction coupled with the Darcy law. Stationary and oscillating convection regimes and oscillating heat explosion are observed. The models with quasi-stationary and unstationary Darcy equation are compared
Mitigation of Harmonics and Inter-Harmonics with LVRT and HVRT Enhancement in Grid-Connected Wind Energy Systems Using Genetic Algorithm-Optimized PWM and Fuzzy Adaptive PID Control
© 2021 Author(s). This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1063/5.0015579The growing installed wind capacity over the last decade has led many energy regulators to define specific grid codes for wind energy generation systems connecting to the electricity grid. These requirements impose strict laws regarding the Low Voltage Ride Though (LVRT) and High Voltage Ride Though (HVRT) capabilities of wind turbines during voltage disturbances. The main aim of this paper is to propose LVRT and HVRT strategies that allow wind systems to remain connected during severe grid voltage disturbances. Power quality issues associated with harmonics and inter-harmonics are also discussed and a control scheme for the grid-side converter is proposed to make the Wind Energy Conversion System insensitive to external disturbances and parametric variations. The Selective Harmonic Elimination Pulse Width Modulation technique based on Genetic Algorithm optimization is employed to overcome over-modulation problems, reduce the amplitudes of harmonics, and thus reduce the Total Harmonic Distortion in the current and voltage waveforms. Furthermore, to compensate for the fluctuations of the wind speed due to turbulence at the blades of the turbine, a fuzzy Proportional-Integral-Derivative controller with adaptive gains is proposed to control the converter on the generator side.Peer reviewedFinal Accepted Versio
Modeling, Simulation and Control of a Doubly-Fed Induction Generator for Wind Energy, Conversion Systems
© 2020 The Author(s). This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License (https://creativecommons.org/licenses/by-sa/4.0/).In recent years, wind energy has become one of the most promising renewable energy sources. Various wind turbine concepts with different generator topologies have been developed to convert this abundant energy into electric power. The doubly-fed induction generator (DFIG) is currently the most common type of generator used in wind farms. Usually the DFIG generator is a wound rotor induction machine, where the stator circuit is directly connected to grid while the rotor’s winding is connected to the grid via a three-phase converter. This paper describes an approach for the independent control of the active and reactive powers of the variable-speed DFIG. The simulation model including a 1.5 MW-DFIG driven by a wind turbine, a PWM back-to-back inverter and the proposed control strategy are developed and implemented using MATLAB/Simulink/SimPowerSystems environment.Peer reviewedFinal Published versio
Impact of the Integration of a STATCOM Controlled by LQG/H2 Regulator in an Energy System
© The Author(s); licensee IIETA, Edmonton, Canada. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/Nowadays, the reactive power consumption is becoming a serious problem for electricity network management. To overcome this problem, several solutions are proposed in the literature. In the present study, the static reactive power compensator (STATCOM) solution is used to keep the network voltage within its rated range. The STATCOM is modeled in the axes of Park reference frame and is driven controlled by a SVPWM strategy. Its control scheme is based on a multivariable Linear Quadratic Gaussian (LQG/H2) controller, which has the advantage of being applied to systems whose condition is not measured. Simulations are performed using the MATLAB/SIMULINK software. Results are presented, compared and discussed.Peer reviewe
Voltage Profile and Power Quality Improvement Using Multicell Dynamic Voltage Restorer
This work is licensed under a Creative Commons Attribution-Share Alike 4.0 International License.Multi-level converter topologies are increasingly being used in various applications due to their high power, high voltage, and low harmonic levels in the output waveforms. These converter topologies produce different output voltage levels and have a highly modular structure. This paper proposes the design of a dynamic voltage restorer (DVR) based on multilevel topology to enhance the voltage profile and improve the power quality in the network. The DVR is an effective, fast-acting device which detects voltage sags and swells in a transmission line and inject a compensating voltage through a boost transformer. A simulation study is carried out under MATLAB/Simulate to demonstrate the performance of the proposed DVR circuit. The simulation results show improved transient response and enhanced power quality in the transmission network.Peer reviewe
ANFIS control of a shunt active filter based with a five-level NPC inverter to improve power quality
© 2021 The Author(s). This is an open access article under the CC BY-SA license (https://creativecommons.org/licenses/by-sa/4.0/).This paper addresses the problem of power quality, and the degradation of the current waveform in the distribution network which results directly from the proliferation of the nonlinear loads. We propose to use a five-level Neutral Point Clamped (NPC) inverter topology for the implementation of the shunt active filter (SAPF). The aim of the SAPF is to inject harmonic currents in phase opposition at the connection point. The identification of harmonics is based on the pq method. A neuro-fuzzy controller based on ANFIS (Adaptive Neuro Fuzzy Inference System) is designed for the SAPF. The simulation study is carried out using MATLAB/Simulink and the results show a significant improvement in the quality of energy and a reduction in Total Harmonic Distortion (THD) in accordance with IEC standard, IEEE-519, IEC 61000, EN 50160.Peer reviewe
Offline Face Recognition System Based on GaborFisher Descriptors and Hidden Markov Models
This paper presents a new offline face recognition system. The proposed system is built on one dimensional left-to- right Hidden Markov Models (1D-HMMs). Facial image features are extracted using Gabor wavelets. The dimensionality of these features is reduced using the Fisher’s Discriminant Analysis method to keep only the most relevant information. Unlike existing techniques using 1D-HMMs, in classification step, the proposed system employs 1D-HMMs to find the relationship between reduced features components directly without any additional segmentation step of interest regions in the face image. The performance evaluation of the proposed method was performed with AR database and the proposed method showed a high recognition rate for this database
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