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[IEEE 2018 25th International Conference "Mixed Design of Integrated Circuits and System" (MIXDES) - Gdynia, Poland (2018.6.21-2018.6.23)] 2018 25th International Conference "Mixed Design of Integrated Circuits and System" (MIXDES) - Optimization of Class-D Amplifier Output Stage for Piezoelectric Actuator Control
摘要： Design of a piezoelectric driver for a microelectromechanical actuator in a small form factor for laser telecommunications is introduced. The driver introduces a number of challenges due to its size and power limitations as a Microelectromechanical Systems (MEMS) actuator. Because of the small form factor, the driver must be integrated into the actuator itself, which limits its size and power. The efficiency of a linear amplifier becomes a major drawback due to the dissipated heat of only 20 W for the Laser Telecommunications Module (LTM), low efficiency of a linear amplifier becomes a major drawback due to the dissipated heat. Switching Class-E amplifiers provide exceptional efficiency compared to non-switching solutions at a price of high frequency harmonics, which allows for higher output power without additional heat dissipation. The efficiency, however, comes at a price of high frequency harmonics, which must be reduced by implementing a High-Energy-Efficiency Interference (HEEI) and Total Harmonic Distortion (THD). Driving a capacitive load, such as a piezoelectric actuator, at a high frequency with a Class-E amplifier requires a matching network to achieve the desired output power. The measurements were performed on a custom-made driver model for piezoelectric stack actuators with 270 V peak-to-peak voltage, 500 kHz switching frequency and a range of capacitive load from 2.1 nF to 20 nF.
关键词： Actuator,Driver,Amplifier,Distortion,LTM.2,Output Stage,SMPS,Class-E,Total,LTM,THD,MEMS,Harmonic,Transmission,Telecommunications,Laser,Module,High-Energy-Efficiency,HEEI,Interference,Piezoelectric,Microelectromechanical
更新于2025-09-23 15:22:29
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Solar hydrogen production via alkaline water electrolysis
摘要： Electricity generation via direct conversion of solar energy with zero carbon dioxide emission is essential from the aspect of energy supply security as well as from the aspect of environmental protection. Therefore, this paper presents a system for hydrogen production via water electrolysis using a 960 Wp solar power plant. The results obtained from the monitoring of photovoltaic modules mounted in pairs on a fixed, a single-axis and a dual-axis solar tracker were examined to determine if there is a possibility to couple them with an electrolyzer. Energy performance of each photovoltaic system was recorded and analyzed during a period of one year, and the data were monitored on an online software service. Estimated parameters, such as monthly solar irradiance, solar electricity production, optimal angle, monthly ambient temperature, and capacity factor were compared to the observed data. In order to get energy efficiency as high as possible, a novel alkaline electrolyzer of bipolar design was constructed. Its design and operating UI characteristic are described. The operating UI characteristics of photovoltaic modules were tuned to the electrolyzer operating UI characteristic to maximize production. The calculated hydrogen rate of production was 1.138 g per hour. During the study the system produced 1.234 MWh of energy, with calculated of 1.31 MWh, which could power 122 houses, and has offset 906 kg of carbon or an equivalent of 23 trees.
关键词： Solar tracker,Solar energy,Photovoltaic module,Hydrogen,Alkaline electrolyzer,Water electrolysis
更新于2025-09-23 15:21:21
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Effective solar power harnessing using a few novel solar tree designs and their performance assessment
摘要： Solar irradiance being considered as one of the most important alternative sources of energy can be harnessed in the form of electrical power using photovoltaic panels erected under the sun. Optimum conversion of power from solar panels can be obtained by using Maximum Power Point Tracking (MPPT), which involves continuously adjusting the angle of panels according to the change in the angle of falling irradiance. These trackers, however, use some amount of power for operation of MPPT equipment. Various techniques for arranging the solar panels in three dimensions have been suggested for optimizing the output power from them. The inspiration behind arranging the panels are often drawn from the natural trees where the branches and the leaves follow a particular pattern called phyllotaxy which is directly analogous to the Fibonacci number and Golden ratio. In this research work, the power output from two solar tree models based on 3/8 and 2/5 phyllotaxy pattern and solar conventional panel compared under similar irradiance conditions. There are so many phyllotaxy patterns like 1/3, 2/5, 3/8, etc. When the solar panels aligned in different phyllotaxies, then the orientation direction of solar panels are distinct. Each solar panel connected in solar trees is in a different direction, so that they received the maximum amount of sunlight throughout the day as compared to conventional panels which is oriented unidirectional.
关键词： three-dimensional phyllotaxy,photovoltaic module,Solar energy,solar tree,Fibonacci number
更新于2025-09-23 15:21:21
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High-Resolution Aerial Imagery Semantic Labeling with Dense Pyramid Network
摘要： Semantic segmentation of high-resolution aerial images is of great importance in certain fields, but the increasing spatial resolution brings large intra-class variance and small inter-class differences that can lead to classification ambiguities. Based on high-level contextual features, the deep convolutional neural network (DCNN) is an effective method to deal with semantic segmentation of high-resolution aerial imagery. In this work, a novel dense pyramid network (DPN) is proposed for semantic segmentation. The network starts with group convolutions to deal with multi-sensor data in channel wise to extract feature maps of each channel separately; by doing so, more information from each channel can be preserved. This process is followed by the channel shuffle operation to enhance the representation ability of the network. Then, four densely connected convolutional blocks are utilized to both extract and take full advantage of features. The pyramid pooling module combined with two convolutional layers are set to fuse multi-resolution and multi-sensor features through an effective global scenery prior manner, producing the probability graph for each class. Moreover, the median frequency balanced focal loss is proposed to replace the standard cross entropy loss in the training phase to deal with the class imbalance problem. We evaluate the dense pyramid network on the International Society for Photogrammetry and Remote Sensing (ISPRS) Vaihingen and Potsdam 2D semantic labeling dataset, and the results demonstrate that the proposed framework exhibits better performances, compared to the state of the art baseline.
关键词： pyramid pooling module,semantic segmentation,densely connected convolutions,high-resolution aerial imageries
更新于2025-09-23 15:21:21
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Performance analysis of a heat pump-based photovoltaic/thermal (PV/T) system
摘要： Photovoltaic/thermal (PV/T) system produces both heat and electricity simultaneously with the advantages of better space utilization and higher conversion efficiency over individual solar thermal and solar photovoltaic (PV) system when operated separately. The PV/T system can control the operating temperature of PV by passing a heat transfer fluid through a heat exchanger attached to the rear of the modules. The present study analyses the performance of one such in-house built system, where the heat transfer fluid is refrigerant. Refrigerant-based PV/T system involves the integration of evaporator coils of the heat pump and PV module to form a cogeneration type system known as photovoltaic/thermal–solar assisted heat pump (PV/T–SAHP). The prototype of the PV/T–SAHP was fabricated with a double glass PV module instead of a conventional module with polyvinyl fluoride backsheet. Initially, the performance characteristics of the system are analyzed in detail using the experimental observations under a typical clear sky condition during the transition season. Following, the year-round performance of the system is predicted using an already validated numerical model. It was found that the present system can improve the average electrical efficiency by 15.20% and can achieve a coefficient of performance of 2.96.
关键词： Refrigerant-based PV/T system,Thermal management of PV module,Double glass PV module,Heat pump
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Reproducing the a??Framinga?? by a Sequential Stress Test
摘要： The “Framing” (local discoloration along cell edges) was induced by a simple sequential accelerated stress test (consisting of hygrothermal- and UV-stressors) applied to the PV modules with high OTR (oxygen transmission rate) backsheet, irrespective of the inclusion of UV-absorber in poly(ethylene-co-vinyl acetate) (EVA) encapsulant. UV-fluorescence imaging of the PV modules suggests that the spatially-inhomogeneous degradation of EVA material under UV-irradiating conditions is correlated to this “Framing” indicating an underlying common mechanism. These findings would contribute to the development of test procedures to broadly mimic the actual failures observed in fielded PV.
关键词： snail trail,metallization,framing,photovoltaic (PV) module,ultraviolet (UV)-induced degradation
更新于2025-09-23 15:21:01
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Late-stage Customization in Volume Production of Organic Photovoltaics
摘要： Organic photovoltaics (OPV) in free-form shapes have become a unique feature compared to other thin-film photovoltaic technologies. The ability to conform coated layers to any form of shape or structure is a game changer for OPV and creates a paradigm shift in conventional energy businesses. As urban growth prevails, the energy requirement must be compensated by modern means and OPVs provide unique properties where its form or shape can be fully customized. This creates a synergy as they are then easily integrated onto structures or even products. By doing so not only the space requirements are diminished but the energy is delivered directly to the point of use rather than having them transported from central harvesting. The present communication discusses the advances in realizing such free-from patterns by structuring the functional layers to shape after they have been deposited which is referred to as late-stage customization. Using this approach, a pre-coated generic OPV material can be converted into any design upon customer request. The advantages include easier planning, shorter lead times in production as well as paving the way towards lean manufacturing.
关键词： renewable energies,mass production,organic photovoltaics (OPV),laser scribing,slot-die coating,module customization,roll-to-roll fabrication,dielectric material
更新于2025-09-23 15:21:01
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The mathematical and experimental analysis on the steady-state operating temperature of bifacial photovoltaic modules
摘要： The operating temperature of bifacial photovoltaic (PV) module affects its power generation and reliability. Combined with view factor model of ground reflectivity on module backside, a thermal steady-state model is established to analyze the thermal performance of bifacial module in this paper. The module operating temperatures under three different installation conditions of roof cement ground, water surface and grassland are calculated and simulated by ANSYS software, and the experiments are designed to analyze and verify it. Based on the difference of reflectivity and heat capacity of different ground for the PV module installation, the effects of ground type and module material on bifacial module temperature and its mechanism are analyzed quantitatively. According to the simulation and experiment results, the operating temperatures of the bifacial modules installed on the roof cement ground, water surface and grassland are 44.7 (cid:1)C, 41.5 (cid:1)C, 43.2 (cid:1)C respectively, under the setting environment condition with specific irradiance, wind speed and ambient temperature. The temperature difference of 1.7 (cid:1)C e3.2 (cid:1)C is caused by ground reflectivity and temperature. The operating temperature difference between glass-glass and glass-backsheet module is less than 0.4 (cid:1)C under the standard condition. The conductivity and emissivity of encapsulation material does not show strong influence on module operating temperature.
关键词： Bifacial PV module,Solar cell,Ground reflectivity,Operating temperature
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Activation Energy for Solder Bond Degradation: Thermal Cycling of Field-aged Modules at Multiple Upper Temperatures
摘要： The reliability of solder joints in the solar cell metallization-interconnect system influences the lifetime of photovoltaic modules. Two field-aged modules—one with Sn62Pb36Ag2 solder at the solder joints (Solarex MSX 60), and the other with the standard Sn60Pb40 solder (Siemens M55)—were subjected to a modified thermal cycling (TC) test of IEC 61215. Three sections in each module were maintained at 85℃, 95℃, and 105℃ during the 15-minute high temperature dwell time. Current equivalent to the module short-circuit current was injected through the module when the chamber temperature was above 25℃ to simulate regular field operation. This novel approach aims to induce thermomechanical fatigue (TMF) at the solder joints and intermetallic compound (IMC) formation at the metal/solder interfaces. The activation energy (Ea) for solder bond degradation was calculated based on the series resistance (Rs) increase in TC testing rather than power drop to avoid the effect of confounding variables. Module-level Rs increase in MSX 60 module after TC800 cycles and in M55 module after TC400 cycles was 1.22% and 183.7%, respectively. The Ea determined for the module with 2wt% Ag is 0.24 eV and for that with the standard solder is 0.27 eV. The solder bond degradation seems to have been driven by TMF rather than IMC formation for both modules.
关键词： series resistance,PV module,solder bond degradation,thermal cycling,field-aged,activation energy
更新于2025-09-23 15:21:01
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Bandgap-Tuned CuInS <sub/>2</sub> /ZnS Core/Shell Quantum Dots for a Luminescent Downshifting Layer in a Crystalline Silicon Solar Module
摘要： CuInS2 (CIS) quantum dots (QDs) were investigated as a luminescent downshifting (LDS) material that converts near-ultraviolet (UV) light to visible light and were applied to a single crystalline silicon (c-Si) solar module that has no spectral sensitivity in the near-UV region. The bandgap of the CIS/ZnS core/shell QDs was successfully adjusted to ~3 eV, which was adequate for the LDS layer in solar devices, by changing the molar ratio of Cu/In. CIS/ZnS/ZnS core/shell/shell QDs with 59.9% absolute photoluminescence (PL) quantum yield were prepared by the hot-injection method and embedded in ethylene vinyl acetate copolymer (EVA) resin to fabricate QD@EVA films as the LDS layer. The PL intensity of the QD@EVA films under near-UV excitation monotonically increased with increasing QD concentration. The films were attached to a commercial single c-Si solar module. The advantages and drawbacks of the films were discussed based on the results of incident photon-to-electron conversion efficiency and current-voltage curve measurements.
关键词： CuInS2/ZnS,quantum dot,nanocomposite film,solar module,nanophosphor,luminescent downshifting layer,photoluminescence
更新于2025-09-23 15:21:01