52 research outputs found

    An Optimized Combination of a Large Grid Connected PV System along with Battery Cells and a Diesel Generator

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    Environmental, economical and technical benefits of photovoltaic (PV) systems make them to be used in many countries. The main characteristic of PV systems is the fluctuations of their output power. Hence, high penetration of PV systems into electric network could be detrimental to overall system performance. Furthermore, the fluctuations in the output power of PV systems make it difficult to predict their output, and to consider them in generation planning of the units. The main objective of this paper is to propose a hybrid method which can be used to control and reduce the power fluctuations generated from large grid- connected PV systems. The proposed method focuses on using a suitable storage battery along with curtailment of the generated power by operating the PV system below the maximum power point (MPP) and deployment of a diesel generator. These methods are analyzed to investigate the impacts of implementing them on the economical benefits that the PV system owner could gain. To maximize the revenues, an optimization problem is solved

    Wind Turbine Simulators

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    Small Scale Wind Energy Conversion Systems

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    Study of Novel Power Electronic Converters for Small Scale Wind Energy Conversion Systems

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    This chapter proposes a study of novel power electronic converters for small scale wind energy conversion systems. In this chapter major topologies of power electronic converters that used in wind energy converter systems have been analysed. Various topologies of DC/AC single stage converters such as high boost Z-source inverters (ZSI) have been investigated. New proposed schemes for inverters such as multilevel and Z-source inverters have been studied in this proposed chapter. Multilevel converters are categorized into three major groups according to their topologies which are diode clamped multilevel converters (DCM), cascade multilevel converters (CMC) with multiple isolated dc voltage sources and flying capacitor based multilevel converters (FCMC). Z-source inverters are divided to ZSI, qZSI and trans-ZSI types. Trans-ZSI is mostly used for high step-up single stage conversions

    Framework of Intelligent Systems to Support Project Scope

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    Application of DC-DC Converters at Renewable Energy

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    Photovoltaics usually produce low voltage at their outputs. So, in order to inject their power into utility grids, the output voltage of solar panels should be increased to grid voltage level. Usually, the boost DC-DC converters will be connected between solar panels and grid-connected inverters to boost the panels\u27 output voltage to more than 320 V (for 380/220 utilities). Various DC-DC converter topologies have been proposed in the past three decades to boost the photovoltaic panels\u27 output voltage which will be discussed in this proposal. In order to increase the life span of photovoltaic panels, the DC-DC converts should absorb continuous low ripple current from solar panels. Maximum power point tracking (MPPT) is an algorithm implemented in photovoltaic (PV) inverters by DC-DC technology to continuously adjust the impedance seen by the solar array to keep the PV system operating at, or close to, the peak power point of the PV panel under varying conditions, like changing solar irradiance, temperature, and humidity. In this research work, various topologies of DC-DC converters that are suitable for renewable energy applications along with the advantages and disadvantages of control methods and the stability of converters with related control methods are discussed

    Orius albidipennis (Heteroptera: Anthocoridae): Intraguild predation of and prey preference for Neoseiulus cucumeris (Acari: Phytoseiidae) on different host plants

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    A widespread interaction in natural enemy populations is intraguild predation (IGP), the intensity and outcome of which may be influenced by several factors. This study examined the influence of host plant characteristics on IGP between Orius albidipennis (Reuter) and Neoseiulus cucumeris (Oudemans) in laboratory experiments. The intraguild predation between the two predators was bi-directional, but predation by N. cucumeris on O. albidipennis is presumably of negligible importance. Orius albidipennis preyed uponmite eggs and adults in the absence of Thrips tabaci (Lindeman) (Thysanoptera: Thripidae), but in its presence predation on mite eggs was abandoned and predation on adult mites unchanged (sweet pepper) or reduced (eggplant, cucumber). The IGP-level of O. albidipennis on N. cucumeris was highest on sweet pepper and lowest on cucumber. Inclusion of host plant aspects in evaluations of the IGPpotential between predators intended for simultaneous applications for biocontrol is thus of importance

    A new approach to design switching strategy for the buck converters

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    In this paper, a novel method is developed to control switched DC-DC Buck converters. The circuit dynamic is described as an affine linear switched system. Utilizing switched systems theory, a switching state-feedback law is derived to asymptotically stabilize the desired equilibrium point and also minimize a guaranteed cost. The efficiency of the proposed method is illustrated by simulation which verifies the improvement of the obtained results compared with the literatures

    The tracheal virome of broiler chickens with respiratory disease complex in Iran: the metagenomics study

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    Background and Objectives: Avian respiratory disease complex (RDC) is one of the most detrimental economic diseases that affected different parts of the world. Various pathogens cause the disease, but the most significant viral pathogens include avian influenza virus (AIV), infectious bronchitis virus (IBV), and Newcastle disease virus (NDV) are the most prevalent. To detect these pathogens, various methods have been discovered in the last decades. Detection and characterization of viruses by metagenomics methods have improved our knowledge about the role of virome in the avian complex respiratory disease. Materials and Methods: This research investigates the viral pathogen populations that mostly participate in emerging these diseases using the NGS method RNA-sequencing. In surveillance of ten broiler farms from different cities with respiratory symptoms, trachea samples were collected to determine the pathogenic virome causing the disease. Results: In this metagenomics analysis, nine viral families were identified, comprising 72.82% of RNA viruses, 24.32% of RT viruses, and 2.86% of DNA viruses. RNA viruses had the highest contribution to the respiratory disease complex instead of disease, including paramyxoviridae, orthomyxoviridae, coronaviridae, and picornaviridae viruses. Other viruses from the RNA viruses and DNA virus families were also identified in addition to these results. Conclusion: This research suggests that studies of pathogenic viromes in different diseases can help monitor different diseases and predict their future occurrence
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