Nova metoda izoliranja osnovne komponente signala zasnovana na transformaciji elementarnog vala

In this paper, a new method is proposed for improving the fundamental extraction by wavelet transform. This method uses the discrete wavelet transform (DWT), FIR filter and inverse discrete wavelet transform (IDWT). In the proposed method, frequency interference is allowed to occur at the extracted frequency bands by DWT. DWT output signal is filtered by FIR then the IDWT is used to reconstruct the filtered signal. This process improves the quality of extracted fundamental component and transient response. To verify the validity of the proposed method, the electric distribution system of electric arc furnaces (EAFs) of Mobarakeh Steel Company is simulated in MATLAB software. Finally the fundamental component of the voltage of point of common coupling (PCC) is extracted by proposed method and DWT and IDWT method.U radu je predložena nova metoda za unaprjeđenje određivanja osnovne komponente signala korištenjem transformacije elementarnog vala. Metoda koristi diskretnu transformaciju elementarnog vala (DWT), FIR filter i inverznu iskretnu transformaciju elementarnog vala (IDWT). Metoda dopušta interferenciju s DWT u frekvencijskom rasponu osnovne komponente. Izlazni DWT signal filtriran je pomoću FIR-a, a zatim se primjenjuje IDWT za rekonstrukciju filtriranog signala. Ovaj proces poboljšava kvalitetu određene osnovne komponente i odziva prijelazne pojave. Za provjeru vjerodostojnosti predložene metode, u MATLAB programu simuliran je sustav za elektrodistribuciju elektrolučne peći (EAF) za poduzeće Mobarakeh Steel Company. Konačno, osnovna komponenta napona točke zajedničkog spoja (PCC) određena je predloženom metodom uz DWT i IDWT

Apport de l'UPFC à l'amélioration de la stabilité transitoire des réseaux électriques

Texte intégral accessible uniquement aux membres de l'Université de LorraineThe main prupose of this research is the modeling, the identification of the references and control of UPFC d'UPFC (Unified Power Flow Controller), in order to improve the transient stability of generator connected to an infinite bus. In order to analyse the influence of the UPFC on the network, the mathematical model of a UPFC connected to an infinite bus is presented. Various methods of identification of references ( instantaneous power, decoupled Watt-Var ) and various regulators ( P, PI, IP, RST ) for the shunt part and also series part of the UPFC are studied in the steady state operation. Different methods for identification of the series part like " optimal parameters ", " injection model ", and " state variables " in order to improve the stability of the system, are studied. Finally, a new method for identification based on " state variables " using the local parameters of the system is proposed and tested through the simulations.Ce mémoire porte sur la modélisation, l'identification des références et la commande d'UPFC (Unified Power Flow Controller) destiné à améliorer la stabilité transitoire d'un générateur connecté à un réseau infini. Afin d'analyser l'influence de l'UPFC sur le réseau , le modèle mathématique d'un UPFC connecté à un réseau électrique est présenté. Différentes méthodes d'identification de référence ( puissance instantanée, Watt-Var découplé ) ainsi que les régulateurs associés (P, PI, IP, RST ) pour les parties shunt et série de l'UPFC en régime permanent sont étudiés. Différentes méthodes d'identification de référence de la partie série afin d'améliorer la stabilité du système comme " paramètres optimaux ", " modèle d'injection " et " variable d'état " sont étudiées. Enfin, une nouvelle méthode d'identification basée sur la méthode de " variables d'état " en utilisant les paramètres locaux du système est proposée et examinée par des simulations

Apport de l'UPFC à l'amélioration de la stabilité transitoire des réseaux électriques

Ce mémoire porte sur la modélisation, l'identification des références et la commande d'UPFC (Unified Power Flow Controller) destiné à améliorer la stabilité transitoire d'un générateur connecté à un réseau infini. Afin d'analyser l'influence de l'UPFC sur le réseau , le modèle mathématique d'un UPFC connecté à un réseau électrique est présenté. Différentes méthodes d'identification de référence ( puissance instantanée, Watt-Var découplé ) ainsi que les régulateurs associés (P, PI, IP, RST ) pour les parties shunt et série de l'UPFC en régime permanent sont étudiés. Différentes méthodes d'identification de référence de la partie série afin d'améliorer la stabilité du système comme " paramètres optimaux ", " modèle d'injection " et " variable d'état " sont étudiées. Enfin, une nouvelle méthode d'identification basée sur la méthode de " variables d'état " en utilisant les paramètres locaux du système est proposée et examinée par des simulations.The main prupose of this research is the modeling, the identification of the references and control of UPFC d'UPFC (Unified Power Flow Controller), in order to improve the transient stability of generator connected to an infinite bus. In order to analyse the influence of the UPFC on the network, the mathematical model of a UPFC connected to an infinite bus is presented. Various methods of identification of references ( instantaneous power, decoupled Watt-Var ) and various regulators ( P, PI, IP, RST ) for the shunt part and also series part of the UPFC are studied in the steady state operation. Different methods for identification of the series part like " optimal parameters ", " injection model ", and " state variables " in order to improve the stability of the system, are studied. Finally, a new method for identification based on " state variables " using the local parameters of the system is proposed and tested through the simulations.NANCY1-SCD Sciences & Techniques (545782101) / SudocSudocFranceF

Improved secondary control for optimal total harmonic distortion compensation of parallel connected DGs in islanded microgrids

This study proposes a two-layer hierarchical control to actualize optimal total harmonic distortion (THD) compensation in different buses of parallel-connected inverters in islanded microgrids which had not been studied so far. The proposed secondary layer is used to realize THD compensation of sensitive load bus (SLB) and make distributed generators (DGs) distribute the compensating efforts between them according to their rated capacity. It is noteworthy that improving THD at the SLB can lead to an increase in THD at local buses and/or DG terminals. Although the THD limitations of these buses are not as strict as the THD limitation of SLB, it is necessary to control them within their allowed range. This important problem is not well studied in the literature. A novel complementary part is designed and added to the secondary control to tune the compensation portion of each DG while the THD limitations in DG terminals and local buses are considered. The proposed method actualizes a multi-level voltage quality control in multi-bus islanded microgrids with parallel DGs through a simple yet effective solution. Furthermore, considering the DGs peak current limitation is added to the controller and a method for calculating this peak value is proposed

Stand-Alone Phovoltaic System Operation with Energy Management and Fault Tolerant

International audienceThis paper presents a stand-alone photovoltaic (PV) system with a fault tolerant operation capability. An energy management method is provided to keep the balance between produced and consumed energy instantaneously. As the storage element, an Ultra-Capacitor (UC) pack is used for facing high frequency variation of the load/source, and batteries are in charge of slow load /source variations. A Maximum Power Point Tracking (MPPT) algorithm is applied to control the boost converter of the PV source to achieve the maximum power. In order to improve the micro-grid service continuity and reliability, a fast fault diagnosis method based on the converter current shape for PV source is applied. Finally, the validity of the proposed energy management and the fault diagnosis method is confirmed by the simulation and experimental results

Reliable FPGA-based Solar Energy Production

International audienceThis paper presents a stand-alone photovoltaic (PV) system with a hybrid storage unit operation under normal and faulty condition. An energy management method based on the use of a hybrid storage for the solar energy production system is presented. The storage system consists a battery and an Ultra Capacitor (UC) pack. The UCs are used for facing high frequency variation of the load/source, while the batteries are in charge of slow load /source variations. Generally, in a PV system boost converters are used to connect solar panels to the DC bus. These converter allows to achieve the maximum power of the PV source by applying a Maximum Power Point Tracking (MPPT) algorithm. On the other hand, the power electronic semiconductor switch faults are popular in DC-DC converters. In order to improve the micro-grid service continuity and reliability, a fast fault detection method based on the converter current shape and one redundancy based fault tolerant converter for PV source is proposed in this paper. The validity of the proposed energy management and associated control system, the fault detection method and fault tolerant strategy are confirmed by the simulations, HIL and experimental results

Reliable FPGA-based Solar Energy Production

International audienceThis paper presents a stand-alone photovoltaic (PV) system with a hybrid storage unit operation under normal and faulty condition. An energy management method based on the use of a hybrid storage for the solar energy production system is presented. The storage system consists a battery and an Ultra Capacitor (UC) pack. The UCs are used for facing high frequency variation of the load/source, while the batteries are in charge of slow load /source variations. Generally, in a PV system boost converters are used to connect solar panels to the DC bus. These converter allows to achieve the maximum power of the PV source by applying a Maximum Power Point Tracking (MPPT) algorithm. On the other hand, the power electronic semiconductor switch faults are popular in DC-DC converters. In order to improve the micro-grid service continuity and reliability, a fast fault detection method based on the converter current shape and one redundancy based fault tolerant converter for PV source is proposed in this paper. The validity of the proposed energy management and associated control system, the fault detection method and fault tolerant strategy are confirmed by the simulations, HIL and experimental results

Modélisation par objets réutilisables : fragmentation en éléments d'une architecture de terre. Application au petit caravansérail de la citadelle de BAM (Iran)

International audienceThe city of Bam, in south-eastern Iran is one of the greatest mud brick architectures in the world. Vastly damaged during the earthquake of 2003, a virtual 3D reconstruction is started for its most remarkable buildings. The modeling process of small caravanserai is presented here. This 3-D reconstruction uses documents from a variety of sources with different chronology. The architecture to rebuild imposes an analysis of morphological and constructive nature of the mud brick building and a research on the methodology related to the modeling tools of the chosen software (3DSMax).La ville de Bam, dans la partie sud-est de l’Iran est l’un des plus grands ensembles au monde fait de terre. Détruite en grande partie lors du tremblement de terre de 2003, elle fait l’objet, pour ses bâtiments les plus remarquables d’une reconstitution virtuelle. La modélisation en cours du petit caravansérail est présentée ici. Cette reconstitution utilise des documents de sources et d’époques variées. L’architecture à reconstituer impose une analyse de la nature morphologique et constructive du bâtiment de terre ainsi que la recherche d’une méthodologie liée aux outils de modélisation du logiciel choisi (3DSMax)