THE PHOTOVOLTAIC SYSTEM AND EFFICIENCY OF DC TO AC BuNa INVERTER

Solar energy nowadays is considered being one of the renewable resources that has the highest rate of growth. BuNa inverter efficiently transforms a DC power source to AC source,with better characteristics in comparison with other inverters.The purpose of this inverter is to supply the LED bulbs only with the same power, more efficiently than other inverters.The input voltage is 12 Volt from battery and output is 220 Volt AC pure sine wave without loads.The consumption of inverter without loads is 0.1 A from battery or 1.2 Watt.This type of inverter has many advantages:no electrical shock hazard,protected input from wrong connection,output is protected from short circuit,after disconnected from short circuit the LED bulbs will light againwithout causing any damage.Moreover,it can be a great device for hospitals,countries without electricity,schoolsetc..The use of this inverter would help people in rural countries have lights in their everyday life

Switched capacitor converters:a new approach for high power applications

High-power, high-voltage and high voltage-conversion ratio DC-DC converters are an enabling technology for offshore DC grids of the future. These converters are required to interface between offshore wind farms and an offshore DC grid and a key design issue is the size and weight of the converter, which significantly impacts the cost of the associated off-shore platform. In addition to this application, some rural communities, particularly in Canada, Australia and South Africa,which are located far away from the electrical power generators, can take the advantages of this technology by tapping into existing HVDC transmission line using a high voltage-conversion ratio DC-DC converter. The work described in this thesis is an investigation as to how such DC-DC converters may be realised for these applications. First a review of existing DC-DC converters was carried out to assess their suitability for the target applications. A classification of DC-DC converters into Direct and Indirect converters was proposed in this work based on the manner in which the energy is transferred from the input to the output terminal of the converter. Direct DC-DC converters, particularly Switched Capacitor(SC) converters are more promising for high-voltage, high-power and high voltage-conversion ratio applications, since the converter can interface between the low-voltage and the high-voltage terminals using low-voltage and low-power power electronic modules. Existing SC topologies were examined to identify the most promising candidate circuits for the target applications. Four SC synthesis techniques were proposed in order to derive new SC circuits from existing topologies. A new 2-Leg Ladder, modular 2-Leg Ladder and bi-pole 2-Leg Ladder were devised, which had significant benefits in terms of size and weight when compared with existing circuits. A scaled power 1 kW converter was built in the laboratory in order to validate the analysis and compare the performance of the new 2-Leg ladder circuit against a conventional Ladder circuit, where it was shown that the new circuit had higher efficiency, smaller size and lower output voltage ripple than the Ladder converter

Terahertz metamaterial devices: from thickness and material dependence to perfect absorption

Metamaterials consist of subwavelength unit cells periodically patterned to exhibit extraordinary electromagnetic properties that do not exist in naturally occurring materials. The far-infrared, or terahertz frequency region of the electromagnetic spectrum is ripe with potential with metamaterials providing a promising technological route towards developing application. Metamaterial “perfect absorbers”, typically configured with three layers as metamaterials-dielectric-ground, have attracted tremendous interest due to near unity absorption of incident electromagnetic radiation over a designed frequency range, with the device having subwavelength thickness. Several theories have been developed to understand the physics of perfect absorption. However, it is important to develop alternative numerical and analytical strategies that transparently connect with the electromagnetic and dielectric properties of the constituent materials to better understand how experimentally accessible parameters ultimately determine the absorption. First, this dissertation introduces a metamaterial absorber with air as spacer layer instead of dielectric materials. In the absence of dielectric material loss, the design can achieve three times higher quality factor compared to traditional designs. Additionally, the absence of the spacer material yields the possibility to access the space between the metamaterial layer and the ground plane inspiring a microfluidic channel integrated sensing device with sensitivity more than three times of the reported results. Second, this dissertation investigates the dependence of the metamaterial absorption maxima on the spacer layer thickness and the reflection coefficient of the metamaterial layer obtained in the absence of the ground plane layer. We observed that the absorption peaks redshift as the spacer thickness is increased, in excellent agreement with the analysis. Third, this dissertation presents a detailed analysis of the conditions that result in unity absorption in metamaterial absorbers. These simple expressions reveal a redshift of the unity absorption frequency with increasing loss that, in turn, necessitates an increase in the thickness of the dielectric spacer. Our findings can be widely applied to guide the design and optimization of the metamaterial absorbers and sensors

PV System Design and Performance

Photovoltaic solar energy technology (PV) has been developing rapidly in the past decades, leading to a multi-billion-dollar global market. It is of paramount importance that PV systems function properly, which requires the generation of expected energy both for small-scale systems that consist of a few solar modules and for very large-scale systems containing millions of modules. This book increases the understanding of the issues relevant to PV system design and correlated performance; moreover, it contains research from scholars across the globe in the fields of data analysis and data mapping for the optimal performance of PV systems, faults analysis, various causes for energy loss, and design and integration issues. The chapters in this book demonstrate the importance of designing and properly monitoring photovoltaic systems in the field in order to ensure continued good performance

Investigation of a Method to Reduce Cavitation in Diesel Engine Bearings

Sonoluminescence is the effect of producing light from sound and occurs when a gas bubble is trapped in a fluid filled cavity and is forced to collapse under a barrage of sound waves. Frenzel and Schultes discovered this phenomenon in 1934 while exposing acoustic waves to photographic plates. This effect was not well understood until 1988 when Crum and Gaitan discovered the necessary conditions for producing single bubble sonoluminescence in the laboratory. The luminescence is a result of the bubble violently collapsing from sound waves and this shares a close association with vibratory cavitation. Cavitation erosion is known to cause damage to rotational machinery when the collapse is near to surfaces due to the high pressures associated with bubble collapse. With these high pressures and temperatures there is a considerable amount of damage to the outside layer of a bearing, thereby, reducing its useful life. An experiment was constructed to generate sonoluminescence in the laboratory in order to obtain a greater understanding of this phenomenon and its association with bubble cavitation. Most of the research was done to investigate how to obtain single bubble sonoluminescence under different conditions and to determine how to detect it. Success in this has inspired several theories on how to use the methods for generating sonoluminescence to control cavitation in fluids under industrial conditions

Studies and Cooling of Highly Charged Ion Ensembles in the ARTEMIS Trap and High-Precision Mass Measurements of 221Fr, 219Rn, 213Bi, 211Pb, 209Pb, 207Tl and 207Pb at SHIPTRAP

Penning traps open up unique experimental possibilities for mass spectrometry and spectroscopy of atomic ions with high precision. Two such experiments based on Penning traps are SHIPTRAP and ARTEMIS at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt. The ARTEMIS experiment is designed to measure the magnetic moment (g-factor) of an electron in heavy, highly charged ions at the 10−9 level, by the means of laser-microwave double-resonance spectroscopy. Such measurements represent highly stringent tests of QED in extreme fields. The ion of choice for the demonstration and development of the experimental methods is 40Ar13+, which can be produced internally in the trap, for later measurements 209Bi82+ is foreseen. For each of the measurements, the preparation of a cleaned and cooled cloud of ions in the spectroscopy trap is necessary. In this work, the system is optimised for non-destructive detection and cooling of the ions, and production, transport, cooling, selection and storage of the Ar13+ ions are systematically demonstrated. Precision mass measurements of the long-lived decay products of 225Ac and 223Ra are carried out at SHIPTRAP, using the phase-imaging ion-cyclotron-resonance technique. The masses of 221Fr, 219Rn, 213Bi, 211Pb, 209Pb, 207Tl and 207Pb are measured with a relative precision of 10−9, allowing an increase in the accuracy of other masses in this region. Some of these masses find direct input into the g-factor measurements, such as in the case of 209Bi, which is of interest to ARTEMIS. Furthermore, the doublet 205Tl / 205Pb, which is of great significance in nuclear astrophysics, is also linked to the measured masses

Distributed light sources for photocatalytic water treatment

In dit proefschrift wordt een nieuwe fotokatalytische reactor met gedistribueerde lichtbronnen gepresenteerd. De nieuwe fotokatalytische reactor maakt gebruik van draadloze energie overdracht om ultraviolet-licht-emitterende diodes (UV-LEDs) van energie te voorzien. De draadloze UV-LEDs worden gedistribueerd door de reactor en verdelen hun licht over het oppervlakte van de fotokatalyst

Modeling of pv module and dc/dc converter assembly for the analysis of induced transient response due to nearby lightning strike

Photovoltaic (PV) systems are subject to nearby lightning strikes that can contribute to extremely high induced overvoltage transients. Recently, the authors introduced a 3D semi-analytical method to study the electromagnetic transients caused by these strikes in a PV module. In the present paper we develop an improved model of the PV module that: (a) takes into account high-frequency effects by modelling capacitive and inductive couplings; (b) considers the electrical insulation characteristics of the module; (c) includes the connection to a DC/DC converter. The whole process involves three major steps, i.e., the magnetic-field computation, the evaluation of both common-mode-and differential-mode-induced voltages across the PV module, and the use of the calculated voltages as input to a lumped equivalent circuit of the PV module connected to the DC/DC converter. In such a framework, the influence of the PV operating condition on the resulting electrical stresses is assessed; moreover, the relevance or insignificance of some parameters, such as the module insulation or the frame material, is demonstrated. Finally, results show that the induced overvoltage are highly dependent both on the grounding of the conducting parts and on the external conditions such as lightning current waveforms and lightning channel (LC) geometry

University Physics Volume 2

University Physics is a three-volume collection that meets the scope and sequence requirements for two- and three-semester calculus-based physics courses. Volume 1 covers mechanics, sound, oscillations, and waves. Volume 2 covers thermodynamics, electricity and magnetism, and Volume 3 covers optics and modern physics. This textbook emphasizes connections between theory and application, making physics concepts interesting and accessible to students while maintaining the mathematical rigor inherent in the subject. Frequent, strong examples focus on how to approach a problem, how to work with the equations, and how to check and generalize the result.https://commons.erau.edu/oer-textbook/1002/thumbnail.jp