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Effect of the Orientation Schemes of the Energy Collection Element on the Optical Performance of a Parabolic Trough Concentrating Collector
摘要： While the circular shape is currently the proven optimum design of the energy collection element (ECE) of a parabolic trough collector, that is yet to be confirmed for parabolic trough concentrating collectors (PTCCs) like trough concentrating photovoltaic collectors and hybrid photovoltaic/thermal collectors. Orientation scheme of the ECE is expected to have significant effect on the optical performance including the irradiance distribution around the ECE and the optical efficiency, and therefore, on the overall energy performance of the PTCC. However, little progress addressing this issue has been reported in the literature. In this study, a thorough investigation has been conducted to determine the effect of the orientation schemes of ECE on the optical performance of a PTCC applying a state-of-the-art Monte Carlo ray tracing (MCRT) technique. The orientation schemes considered are a flat rectangular target and a hollow circular, semi-circular, triangular, inverted triangular, rectangular and rectangle on semi-circle (RSc). The effect of ECE defocus, Sun tracking error and trough rim angle on the optical performance is also investigated. The MCRT study reveals that the ECE orientation schemes with a curved surface at the trough end showed much higher optical efficiency than those with a linear surface under ideal conditions. ECEs among the linear surface group, the inverted triangular orientation exhibited the highest optical efficiency, whereas the flat and triangular ones exhibited the lowest optical efficiency, and the rectangular one was in between them. In the event of defocus and tracking errors, a significant portion of the concentrated light was observed to be intercepted by the surfaces of the rectangular and RSc ECEs that are perpendicular to the trough aperture. This is an extended version of a published work by the current authors, which will help to design an optically efficient ECE for a parabolic trough concentrating collector.
关键词： optical efficiency,optical performance,concentrating solar power,parabolic trough concentrating collector,irradiance distribution,Monte Carlo ray tracing
更新于2025-09-23 15:23:52
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Contact Lenses || Optics and Lens Design
摘要： Some aspects of contact lens design and optics are rarely applied nowadays, as they are less relevant to modern practice, but readers may still need to refer to them. They are available at: https://expertconsult.inkling.com/, whereas the more relevant topics are included here. The appendix, available at: https://expertconsult.inkling.com/, also describes various equations that are used in contact lens work, while the online resources include programs relating to both the optics and to lens design. There are two main aspects to be considered when dealing with the optics of contact lenses: the effects on the wearer of the optical differences from spectacles and the necessity for the practitioner to understand the components which affect the back vertex power (BVP) of the contact-lens/liquid*-lens system. There is some overlap of these two aspects, but for the sake of convenience they are discussed separately in the first two sections of the chapter. In the second section a set of approximate rules is included, the use of which should permit practitioners to make quick and reasonably accurate estimates of changes in power caused by altering certain lens parameters. The Cartesian sign convention2 is used throughout. For further understanding of the basic principles involved, readers are referred to the works of Bennett (1985), Tunnacliffe (1993), Freeman and Hull (2003), Douthwaite (2006) and Rabbetts (2007).
关键词： Lens Design,Astigmatism,Optics,Bifocal Contact Lenses,Power Variations,Contact Lenses,Ocular Refraction,Aberrations,Spectacles
更新于2025-09-23 15:23:52
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Dynamic Wireless Power Transfer for Cost-Effective Wireless Sensor Networks using Frequency-Scanned Beaming
摘要： A simple adaptive 1D frequency-s scanning method is proposed for radiative Wireless Power Transfer (RWPT) systems in low-power Wireless Sensor Networks (WSN). As a proof of concept, a directive leaky-wave antenna that scans 1 W output RF power in the angular range from ±10° at 2.4 GHz to ±37° at 2.5 GHz, is used to power a WSN covering an area of 1.2 m x 1.2 m. It is shown that, using a frequency-scanned antenna, a wider area than using a non-scanned directive antenna can be powered without additional expensive equipment. The WPT protocol is described, showing that any sensor in the WSN can select the optimum transmission channel in the 2.4 GHz band, based on Received Signal Strength Indicator (RSSI) measurements, as the coordinator performs a scheduled frequency hopping phase. This maximizes the WPT beaming efficiency and thus the transferred DC power. The optimum channel selection can be performed periodically, which makes the system robust against channel state changes.
关键词： radiative wireless power transfer,Adaptive beaming,frequency-scanned antennas,wireless sensor network
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE Biomedical Circuits and Systems Conference (BioCAS) - Cleveland, OH, USA (2018.10.17-2018.10.19)] 2018 IEEE Biomedical Circuits and Systems Conference (BioCAS) - Wireless Power and Data Link for Ensembles of Sub-mm scale Implantable Sensors near 1GHz
摘要： We describe a custom wireless power and data transmission (WPDT) link and analyze its performance in a prototype implantable sensor system of ensembles of CMOS sensor ASICs (“Neurograins”) embedding 0.5 mm x 0.5 mm planar microcoil antennas. We use near-field RF at ~1 GHz for wireless powering in a resonant 3-coil architecture including an implanted relay coil in a quadrant layout architecture to maximize coverage area and RF transfer efficiency. We demonstrate successful WPDT across antenna cross-section in benchtop proxy physiological tests. Demodulation and analysis of backscattered signals validate the data link fidelity. Our results suggest that this electromagnetic coupling scheme can robustly support a chip density of 250/ cm2 (up to 1024 individual Neurograins in a 2 cm x 2 cm area) and parallel transmitters can be combined to multiply the channel capacity without destructive interference.
关键词： wireless power,brain-computer interfaces,brain-machine interfaces,implantable sensors
更新于2025-09-23 15:23:52
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[IEEE 2018 International IEEE Conference and workshop in óbuda on Electrical and Power Engineering (CANDO-EPE) - Budapest, Hungary (2018.11.20-2018.11.21)] 2018 International IEEE Conference and Workshop in óbuda on Electrical and Power Engineering (CANDO-EPE) - Plasma ignition and current control considerations for magnetron sputtering power supplies
摘要： Physical vapor deposition processes require different types of special power supplies for the ignition and sustaining of the plasma inside the sputtering chamber. The paper identifies some requirements for the design of a pulsed DC converter. Experiments have been carried out to identify the current-voltage characteristics of the vacuum chamber with the supply of different gases, and gas mixtures in the usable pressure domain. The vacuum chamber was supplied with voltage and current impulse trains with various parameters in order to acquire relevant data regarding the gas breakdown in pulsed power mode. A power electronic converter topology and control routine has been proposed, which is suitable for plasma ignition and discharge current control. The proof of concept has been demonstrated with the help of the magnetron sputtering chamber supplied by a test circuit.
关键词： current control,power electronic converter,plasma ignition,magnetron sputtering
更新于2025-09-23 15:23:52
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[IEEE 2018 2nd School on Dynamics of Complex Networks and their Application in Intellectual Robotics (DCNAIR) - Saratov, Russia (2018.10.8-2018.10.10)] 2018 2nd School on Dynamics of Complex Networks and their Application in Intellectual Robotics (DCNAIR) - Autonomous Power Supply System of Magnetron Generators Group
摘要： The issues which emerge at autonomous power supply system development are considered. The objects of power supply are magnetron generators groups as part of technological complex with a distributed supply of microwave energy.
关键词： solar panels,wind generator,power supply system,diesel generator,magnetron
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE Energy Conversion Congress and Exposition (ECCE) - Portland, OR, USA (2018.9.23-2018.9.27)] 2018 IEEE Energy Conversion Congress and Exposition (ECCE) - Desig and Implementation of High Frequency Power Supply with Constant Power Output for Plasma Applications
摘要： In this paper, a full bridge inverter, connected with a hybrid LCLC resonant tank and controlled by the optimum asymmetrical voltage cancellation (OAVC) approach, is presented to achieve high frequency high voltage power supply for plasma applications. The zero voltage switching (ZVS) of each power switch can be achieved by operating the inverter above the resonant frequency of the LCLC tank, which is beneficial for increasing system efficiency and reducing heat sink volume. In addition, the relationship between the voltage, current and the maximum power are deduced so that the plasma loads are able to work near the maximum power point with relative parameters settings. For verification, a 1kW-prototype, operating at 100 KHz, is implemented in the laboratory, and experimental results are presented to validate the parameters design and control strategies.
关键词： high frequency,ZVS,hybrid resonant tank,LCLC inverter,constant power output
更新于2025-09-23 15:23:52
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[IEEE 2018 International Conference on Current Trends towards Converging Technologies (ICCTCT) - Coimbatore (2018.3.1-2018.3.3)] 2018 International Conference on Current Trends towards Converging Technologies (ICCTCT) - Implementation of Differential Power Processing to Optimize the Solar Power Generation
摘要： The objective of this paper is to harvest the optimum power from solar panel using different MPPT techniques for low power application under non-uniform irradiance conditions. The overall power output of photovoltaic system is reduced due to partial shading. A new differential power converter along with INC control algorithm is introduced to reduce the partial shading effect and oscillations of output power.
关键词： Differential power processing,Maximum Power Point Tracking (MPPT) techniques,Photo-Voltaic (PV) array,Maximum Power Point (MPP),Partial Shading Condition (PSC)
更新于2025-09-23 15:22:29
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1-to-N Ring Power Combiners With Common Delta Ports
摘要： In this paper, we present a new 1-to-N way ring combiner that is an adaptation of the ring-hybrid (rat-race) structure. We present the general design guidelines for N-way planar ring combiners based on theoretical analysis of the structures. The proposed 1-to-N way ring structure offers a compact, planar layout that includes a single common delta port. This is beneficial to applications where power monitoring, calibration, or energy recycling can be leveraged. It offers similar loss to other N-way structures. To demonstrate the combiners operation, we present completely passive structures and structures with embedded power amplifiers for 4- and 6-way variants. The designs are optimized for operation in the 5–6 GHz unlicensed bands. The passive 4- and 6-way combiners achieve IL of 1.3 and 1 dB, respectively, with associated port isolations of <?30 dB. The combiners with embedded amplifiers show similar performance and are validated using modulated signals and demonstrate good measured linearity when combining up to 6 amplifiers for output powers >1 W.
关键词： ring-hybrid combiner,high power amplifier,power divider,Power combiner,rat-race combiner
更新于2025-09-23 15:22:29
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Design of Short-Term Forecasting Model of Distributed Generation Power for Solar Power Generation
摘要： Background/Objectives: For efficient PhotoVoltaic (PV) power generation, computing and information technologies are increasingly used in irradiance forecasting and correction. Today the majority of PV modules are used for grid-connected power generation, so solar generation forecasting that predicts available PV output ahead is essential for integrating PV resources into electricity grids. This paper proposes a short-term solar power forecasting system that employs Neural Network (NN) models to forecast irradiance and PV power. Methods/Statistical Analysis: The proposed system uses the weather observations of a ground weather station, the medium-term weather forecasts of a physical model, and the short-term weather forecasts of the Weather Research and Forecasting (WRF) model as input. To increase prediction accuracy, the proposed system performs forecast corrections and determines the correction coefficients based on the characteristics and temperature of PV modules. The proposed system also analyzes the inclination angle of PV modules to predict PV power outputs. Results: In the correlation analysis of the forecasted and measured irradiance, R2 was over 0.85 for all look-ahead periods, indicating a high correlation between the two data. Conclusion/Application: In the future, the proposed forecasting system for solar power generation resources will be further refined and run in real environments.
关键词： Photovoltaic Power Forecasts,Wind Power,Forecasting System,Solar Energy,Distributed Power Generation
更新于2025-09-23 15:22:29