- 标题
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- 实验方案
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Photovoltaic Synchronous Generator (PVSG): Architecture and Control Strategy for A Grid-Forming PV Energy System
摘要： Transforming conventional PV energy system from a grid following one to a grid forming is necessary when PV power generation is dominating the generation mix and replacing traditional synchronous generators. Grid forming PV energy system can provide frequency support functionality which is vital for the stability of the power grid. This paper presents a novel AC coupled solution that transforms an existing grid following PV system to a grid forming one without any hardware and software modification of the PV inverter. The resulting system, the Photovoltaic Synchronous Generator (PVSG), is achieved by an AC coupled supercapacitor-based energy storage system (ESS). The novel control of the PVSG is implemented in the ESS side. The novel control scheme includes a fast and slow instantaneous power controls. The fast-instantaneous power flow control is fulfilled by the DC-link voltage control and AC voltage control. The cascaded voltage source controls enable the fast-instantaneous power balance, while a slow instantaneous power control is used to implement the inertia and grid synchronization. Two important fundamental functions are realized in the PVSG. The first one is the frequency inertia to resist the grid frequency variation where the df/dt-based power control is achieved; the second one is the inertia against the PV intermittent power. The correctness and effectiveness of the proposed PVSG is validated experimentally in a 480V PVSG prototype with TMS320F28379D DSP controller.
关键词： current controlled,power control,PVSG,virtual synchronous generator (VSG),Inertia,voltage controlled,grid-forming inverter,supercapacitors,energy storage system,inverter control
更新于2025-09-16 10:30:52
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Hybrid Process of Laser Heat Treatment and Forming of Thin Plate with a Small Power Semiconductor Laser
摘要： In recent years, the recycling of resources has become important because of the aggravation of global environmental concerns. In light of this, it is necessary to minimize the resource needs of current production systems. This concept is called sustainable development. When this concept is applied to machine tools, the assumption is that small parts should be processed using small machines. Additionally, the diversification of consumer needs and the ephemeralization of product life cycles are progressing in industry. As a result, the overall production system has changed from high-mix low-volume production manufacturing, to variant types in variable quantity. In this background, the cell production system is receiving attention as a production system that can achieve variant types in variable quantity. The cell production system also requires miniaturization and process consolidation of machine tools, which has given rise to the need to consolidate heat treatments, especially as part of the process consolidation of machine tools. Laser beams have proved to be effective heat sources when integrated into heat-treatment processes, such as quenching and tempering on machine tool tables. On the other hand, In the case of the thin plate, it is well known that the deformation of a plate occurs due to laser irradiation, as named a laser forming. The laser forming is also effective to generate the complex shape without a press die set. Thus, we propose that the hybrid process of laser heat treatment and forming of thin plate with a small power semiconductor laser, and demonstrate that the proposed method makes it feasible to generate the hardened sheet metal products with a compact machine tools. Moreover, considering the power consumption in laser quenching and forming process, we investigate an appropriate laser irradiation condition from a view of reducing the environmental burden.
关键词： Laser forming,Compact machine tools,Sustainable manufacturing,Laser heat treatment,Small power semiconductor laser
更新于2025-09-16 10:30:52
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Prediction and Optimization of Deformations in Coupling Mechanism Based Laser Forming of Sheet Metals
摘要： Fabricating three dimensional shaped surfaces from flat sheet metals by laser forming, both out-of-plane and in-plane deformations are required. This article presents the modeling of coupling mechanism activated laser forming of sheet metals based on experimental data for prediction and optimization of bending and thickening deformations. Experiments were performed based on a central composite design of experiments on coupling mechanism based laser metal forming process considering the input process parameters like laser power, scan speed and spot diameter, bending and thickening were taken as the outputs. Neural network and neuro-fuzzy system-based models were developed to carry out both forward and inverse modeling of the laser metal forming process under the coupling mechanism. Multi-objective optimization based on the non-dominated sorting genetic algorithm was used to obtain multiple optimal solutions to achieve different amounts of out-of-plane and in-plane deformations. The proposed method could guide for a suitable selection of the process parameters to produce three-dimensional shapes utilizing coupling mechanism-based laser forming using multiple laser line heating.
关键词： Coupling mechanism,Soft Computing,Laser forming,Multi-objective optimization
更新于2025-09-16 10:30:52
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Anti-escaping of incident laser in rare-earth doped fluoride ceramics with glass forming layer
摘要： Adaptive fluoride ceramic with glass forming layer (GCZBL-Er) used in laser anti-escaping has been prepared by one-step synthesis, and the thickness of glass layer is identified as ~0.41 mm. Blue, green and red emissions of Er3+/Yb3+ codoped fluoride ceramic (CZBL-Er) and glass layer (GZBL-Er) have been investigated under ~980 nm laser pumping. With the forming of thin glass layer on ceramic surface, the absorption intensities on diffuse reflection of GCZBL-Er at 974 nm and 1.53 μm increase by 48% and 53% than those of CZBL-Er. Excited by a 979 nm laser, the presence of the glass layer increases the absolute absorption rate in spectral power from 75% in CZBL-Er to 83% in GCZBL-er, which is consistent with the improvement in the absorbed photon number. In addition, the quantum yield of GCZBL-er complex is raised by 28.4% compared to the case of ceramic substrate by photon quantification. Intense absorption-conversion ability and efficient macroscopical anti-escaping effect confirm the superiority of ingenious structure in the fluoride ceramics with glass forming layer, which provides a new approach for developing the absorption-conversion materials of anti-NIR laser detection.
关键词： fluoride ceramic,absorption-conversion,Er3+/Yb3+ codoped,laser anti-escaping,glass forming layer
更新于2025-09-16 10:30:52
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Effects of Laser Beam Parameters on Bendability and Microstructure of Stainless Steel in Three-Dimensional Laser Forming
摘要： In this study, the e?ects of beam diameter and hatch spacing between the scanning paths on the bendability and microstructural behavior of an AISI 316 stainless-steel sheet in three-dimensional laser forming were investigated. The strain on the heating lines and that between the scanning tracks were numerically investigated to elucidate the e?ects of process parameters. The strain on heating lines and that between scanning tracks were numerically investigated. The increase in hatch spacing caused a larger amount of counter bending to be retained in the una?ected areas between the tracks through a process dominated by a temperature gradient mechanism (TGM), and also caused a lower deformation. The formation of small equiaxed dendrite grains instead of coarse and inhomogeneous austenite grains occurred during the process at a larger beam diameter and smaller hatch spacing, which increased the bendability of the material, owing to the decrease in anisotropy in the microstructure. Moreover, the increase in the grain size of the reheated overlap region of the deformed sample led to a higher bendability. Under these conditions, the microhardness was also increased owing to the grain boundary strengthening e?ect.
关键词： laser forming,track overlap,stainless steel,laser bending,bendability,hatch spacing
更新于2025-09-16 10:30:52
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Hybrid forming mechanism of patternless casting and laser cladding
摘要： In accordance with the requirement of manufacturing dies quickly and economically, a hybrid forming method of stamping dies for automobile panels is proposed. The method combines digital patternless casting and high-power laser cladding. An experimental study is conducted on the hybrid forming process and its trial production and application in the manufacturing of stamping dies for typical panels. Results prove that the laser cladding layer exceeds HRC60 (Rockwell hardness) and thus meets the production efficiency requirement of automobile dies. The rate of defects is well controlled. Compared with traditional technology, this technology has remarkable advantages and advancement.
关键词： forming,rapid tooling,laser cladding,patternless casting,hybrid
更新于2025-09-16 10:30:52
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Investigation of Geometric Characteristics in Curved Surface Laser Cladding with Curve Path
摘要： Laser cladding on curved surfaces is essential in industrial applications for restoration and remanufacturing of high-value parts. This study investigated the in?uence of di?erent factors on clad width, clad height, and dilution rate in curved surface laser cladding with curved path. Mathematical models were developed using central composite designs to predict these geometric characteristics by controlling laser power, scanning speed, gas ?ow, and altering the outside radius of the cylindrical substrate. Analysis of variance and response surface methodology indicated that clad width increased with increasing laser power and reducing scanning speed. Clad height positively correlated to laser power and negatively correlated to the outside radius of the cylindrical substrate. Increasing the laser power while decreasing the scanning speed led to an increase in dilution rate. Afterwards, the geometric characteristics of the clad were improved by optimizing these factors with the target to maximize clad width and height as well as to minimize dilution rate. The di?erence between model predictions and experimental validations for clad width, clad height, and dilution rate were 3.485%, 3.863%, and 6.566%, respectively. The predicted accuracy was veri?ed with these models, and they were able to provide theoretical guidance to predict and control the geometric characteristics of curved surface laser cladding with a curved path.
关键词： central composite design,curved surface,forming control,curve path,laser cladding
更新于2025-09-16 10:30:52
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Online measurement of the surface during laser forming
摘要： The laser forming process is characterized by high temperature gradients and localized deformation. The process uses a laser to introduce thermal strains. The localized deformation along with the high temperature gradients is introduced iteratively which creates a complex and dynamic forming process. To understand the dynamic behavior of the process, various models have been used. A limitation of these models is that verification is commonly based on comparison with the final shape. The present work is an attempt to measure the dynamic response during laser forming. This work will present a laser forming setup for measuring the dynamic response of a v-bend. A 2D laser range scanner was used for measuring a line perpendicular to the laser heating scan path. By scanning multiple samples and changing the relative position of the 2D laser range scanner along the laser heating scan path, a surface can be generated. Analysis of the surface shows that the plate undergoes different deformation profiles during forming—this can help in understanding the changes that incur during laser forming. A case study is performed where the experimental results are compared with a state-of-the-art numerical model with good correlation between results. This shows that the measured dynamic response can be used for improved verification of numerical models of laser forming to increase confidence in the numerical results.
关键词： Online measurements,FEM,Laser forming,AISI 304,Bending angle
更新于2025-09-16 10:30:52
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Optical Fiber Communications (Principles and Applications) || Radio over Fiber
摘要： Radio over Fiber (RoF) technology can integrate advantages of both wireless networks and optical fiber networks. Recently RoF technology has found numerous applications in broadband wireless access communication networks, radio astronomy, RADAR and millimeter-wave communications, antenna array beam-forming, establishment of up- and down-converting links using photonic signals, spectroscopy, imaging, and electronic warfare.
关键词： wireless networks,RoF,radio astronomy,optical fiber networks,millimeter-wave communications,antenna array beam-forming,photonic signals,broadband wireless access,electronic warfare,Radio over Fiber,spectroscopy,RADAR,imaging
更新于2025-09-12 10:27:22
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Photovoltaic effect in bulk heterojunction system with glass forming indandione derivative DMABI-6Ph
摘要： The aim of the work is to evaluate possible use of 2-[[4-(bis(2-trityloxyethyl)amino)phenyl]methylene]indane-1,3-dione (DMABI-6Ph) as light absorbing material for solar cells. DMABI-6Ph is a perspective material due to its good photoelectrical, thermal and chemical properties. The main advantage of DMABI-6Ph is its ability to form amorphous films by wet-casting methods thus allowing using the compound in organic solar cells made from solution. For now most popular materials for solution processable solar cells are polymer P3HT and fullerene derivative PCBM, but lot of investigations are in the field of new low molecular weight materials to replace the polymer. Photoelectrical measurements were made to determine molecule ionization and electron affinity levels of DMABI-6Ph. Difference of 2.06 eV between DMABI-6Ph ionization level and PCBM affinity level was obtained. Accordingly open circuit voltage of system DMABI-6Ph:PCBM was measured up to 0.78 V. The best power conversation efficiency was 0.11 % for the DMABI-6Ph:PCBM mass fraction 2:1. Limiting factor for high efficiency could be low charge carrier mobility which can be increase by additional DMABI-6Ph modification.
关键词： energy levels,glass forming structure,bulk heterojunction,indandione group,power conversion efficiency
更新于2025-09-12 10:27:22