This paper presents a virtual inertia frequency control (VIFC) strategy for two-stage photovoltaic (PV) systems in an islanded micro-grid. By adjusting capacitor voltage and PV output power ...simultaneously, sufficient energy can be guaranteed for inertia synthesis from PV systems directly. Meanwhile, primary and secondary frequency regulation can also be emulated with fast dynamic response. High performance and reliability can be ensured since all the control signals are based on local measurements and no extra phase locked loop (PLL) is needed. Analysis is confirmed via small signal models and simulation studies demonstrate the effectiveness of the proposed method.
Combining the renewable energy system, the Energy Storage (ES) station can maintain stable power transfer between renewable energy systems and power grid. This paper works on real-time simulation for ...multiple energy storage systems under different operating modes. Then taking a large number of ES converters and power grid into account, a modified electromagnetic transient program (EMTP) algorithm is proposed which is fit for the field-programmable gate array (FPGA)-based real-time simulation. By compressing the steps of the traditional EMTP algorithm, the simulation can be completed only by updating the history current source in each simulation cycle. In the meantime, the system is decoupled and multiple subsystems are simulated independently. Furthermore, to fully utilize the high parallelism of FPGA, we design and build a CPU-FPGA-based real-time simulation platform to implement the ES station. Using the simulation platform, we build a model of ES station and connect to the grid through an inverter. The whole system is tested in a single FPGA under different scenarios.
The surfaces of perovskite solar cells (PSCs) are significant in determining the devices’ efficiencies and stabilities. Here, we first uncover that the 4-
tert
-butylpyridine (
t
BP), as an essential ...additive in hole transport layers (HTLs), could recrystallize the amorphous and defective perovskite surface layers and passivate the defective sites on grain surfaces. The reconstruction induces a larger surface work function and mitigates the interface energy level misalignment between perovskite and HTLs, enlarging the photovoltage of the device. Then, we engineer the chemical bonding strength and develop a more effective HTL additive 4-
tert
-butylpiperidine (
t
BPp), which possesses a stronger interaction with perovskite surface defective sites than
t
BP. With the enhanced adsorption, the
t
BPp-reconstructed perovskite surface exhibits lower densities of defects and better stability under the stimuli of heat, light and humidity. As a result, the optimized
t
BPp PSC reaches a champion efficiency of 24.2% with much better operation stability. Tracked at the maximum power point under a continuous bias, the unsealed devices in a N
2
atmosphere can nearly maintain their initial efficiency after continuous light exposure for over 1200 h. Our findings provide an underlying understanding of the HTL additives, which markedly affect the efficiency and stability of n-i-p PSCs.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The role of defects in the charge transfer and transport properties of electrode materials for lithium-ion batteries has recently garnered increased interest. It is widely recognized that ion ...irradiation promotes the formation of defects within a crystalline solid. Among all ion species used for irradiation, protons are expected to create primarily simple Frenkel pair point defects without significantly changing the stoichiometry of the damaged region of the target material. This work investigates the effect of proton irradiation at varying temperatures on the electrochemical properties of anatase TiO.sub.2 nanotube (TiO.sub.2-NT) electrode for lithium-ion battery applications. Anatase TiO.sub.2-NTs are irradiated at both room temperature (25 °C) and 250 °C and compared with non-irradiated control specimens. Characterization by Raman spectroscopy and XRD suggests that the irradiation at both temperatures does not alter the long-range order of the nanotubes. However, high-resolution TEM reveals that defect clusters are formed upon irradiation and increase in size with increasing temperature. Both irradiated samples exhibit increased capacity and enhanced rate capability compared with the non-irradiated control, which can be explained by increased storage sites as well as improved Li.sup.+ diffusivity due to the presence of irradiation-induced defects. This study presents a unique perspective on pathways to engineer functional nanostructured electrode materials by tailoring irradiation conditions.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Recently, food safety has received considerable attention, and various analytical techniques have been employed to monitor food quality. One of the promising techniques in this domain is the ...surface-enhanced Raman scattering (SERS) technique. This study developed a facile, cost-effective SERS method by supporting a wipe-type substrate with a small-head cotton swab. We fabricated Au-nanoparticle (NP)-decorated cotton swabs (CS-Au NP) via the dropwise addition of gold colloid on the cotton fibers. These swabs exhibit reduced gold colloid consumption and a compact fiber structure, allowing for the uniform distribution of Au NPs and easy capture of molecular signals. Experiments were conducted to obtain a CS-Au NP wiper performance optimized for cotton swab selection, NaCl concentration, and Au NP layers. The Raman reporter molecule 4-mercaptopyridine was detected at a concentration of 1 × 10–8 M and a relative standard deviation of ≤10%. The proposed SERS platform enables the facile and reliable detection of food-safety-related molecules such as malachite green on the surface of fruits and vegetables. This paper describes the development of an easy, cost-effective, and environment-friendly method of detecting food-safety-related molecules on various food surfaces through SERS.
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IJS, KILJ, NUK, PNG, UL, UM, UPUK
Abstract
A reasonable structure is crucial for the solar‐to‐chemical conversion process of the integrated Z‐scheme system. Composition modulation provides a new dimension for the optimization of ...Z‐scheme system. Herein, a composition modulated NiWO
4
/Pt/CdS Z‐scheme system is demonstrated for photocatalytic hydrogen generation. Proportions of Ni, W, Cd, and S in NiWO
4
/Pt/CdS are precisely tuned through the ion‐exchange reaction between NiWO
4
and CdS. Important features of the Z‐scheme system in terms of light harvesting, charge separation and charge transfer are optimized accordingly. Bandgap of CdS is tuned continuously from 2.22 to 1.52 eV through controlling the Cd and S contents in NiWO
4
/Pt/CdS. The results of photoluminescence spectrometry and photoelectrochemical analyses demonstrate that the NiS generated from ion‐exchange reaction increase the charge separation and transfer rates. Furthermore, the molar ratio of NiWO
4
to CdS is regulated to a balance state, leading to the decrease of charge recombination. The optimized NiWO
4
/Pt/CdS Z‐scheme system delivers the comprehensive performance of excellent light harvesting and charge separation abilities, low charge recombination rate, and suitable energy band structure for water reduction. The hydrogen generation rate is increased to 14.39 mmol h
‐1
g
‐1
after the optimization. The optimized method brings a new insight into the rational design of Z‐scheme system.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Inn for electric vehicles (EVs) and photovoltaic (PV) is a typical integration of EVs locally consuming renewable energy sources (RES), with features of EV charging, energy storage, and RES ...consumption. In the existing research works, scholars focus on the energy storage system (ESS) as a medium to charge EVs and send back the power to the utility grid and alleviating the information asymmetry between EV owners and grid dispatching agencies with lower costs of distribution network. In this study, a mixed operational mode based on inn for EV and PV with a replaceable EV battery is analysed. The fragmented energy transferring can shift the load more effectively, balance fluctuation of RES, of great significance to optimise the operation of distribution network system. In summary, a comprehensive model of power flow in distribution network with inn for EV and PV is proposed. Based on an improved IEEE 33-node case, the effects of fragmented energy management mode are analysed. Numerical results show that replacing the full-charged battery for EV is more effective for peak load time-shifting and improving consuming of RES power based on the interaction among RES, ESS, and the replaceable EV battery.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
A decentralized control scheme based on backstepping design is proposed in this paper for the grid converters of a multi-terminal dc power integration system. With the proposed method, dc bus voltage ...can be accurately maintained together by several converters through appropriately adjusting their transmitted power according to the power sharing ratio. The system structure is presented and its dynamic model is formulated. The decentralized control laws of the grid converters are developed step by step by designing appropriate Lyapunov functions. The dc bus voltage control and the power sharing performance of the proposed control method are evaluated both under the system normal condition and converter fault condition. Finally, the effectiveness of the proposed scheme is validated through the real-time simulations on NI-PXI platform.
Abstract The demand for cost‐effective and rapid processing of large‐area thin films in the photovoltaic industry has recently driven significant research interest. In this context, among the various ...approaches explored, printing devices, particularly perovskite solar cells (PSCs), have garnered considerable attention due to their potential for scalability and cost efficiency. Besides, solution printing is widely recognized as an appealing strategy for large‐area, cost‐effective, and high‐throughput production of PSCs. However, while substantial progress has been made in this process, challenges related to stability, uniformity, and scalability remain to be addressed. This review critically examines the key printing techniques and substrates employed in PSC fabrication. Then, given the significance of ambient air printing for industrial applications, fundamental challenges associated with achieving ambient air production of PSCs are discussed in detail. Moreover, the formulation strategies of perovskite ink in printing technologies are thoroughly explored, considering its crucial role in determining the performance and stability of printed PSCs. Finally, the printing process for various components of PSCs, including the perovskite absorber layer, charge transport layers (CTLs), and electrodes, is meticulously analyzed, highlighting current achievements and remaining hurdles.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
By means of morphology-conserved transformation, we have synthesized hierarchically structured Mn2O3 nanomaterials with different morphologies and pore structures. The key step of this method ...consists of the formation of a precursor containing the target materials interlaced with the judiciously chosen polyol-based organic molecules, which are subsequently knocked out to generate the final nanomaterials. In the present work, two kinds of precursor morphologies, oval-shaped and straw-sheaf-shaped, have been selectively prepared by hydrothermal treatment of different functional polyol molecules (oval-shape with fructose and straw-sheaf-shape with small beta-cyclodextrin) and potassium permanganate. Thermal decomposition of the precursors resulted in the formation of mesoporous Mn2O3 maintaining the original morphologies, as revealed by extensive characterization. These novel hierarchical nanostructures with different pore sizes/structures prompted us to examine their potential as anode materials for lithium ion batteries (LIBs). The electrochemical results with reference to LIBs show that both of our mesoporous Mn2O3 nanomaterials deliver high reversible capacities and excellent cycling stabilities at a current density of 200 mA g-1 compared to the commercial Mn2O3 nanoparticles. Moreover, the straw-sheaf-shaped Mn2O3 exhibits a higher specific capacity and a better cycling performance than the oval-shaped one, due to the relatively higher surface area and the peculiar nanostrip structure resulting in the reduced length for lithium ion diffusion. Morphology-conserved transformation yields two kinds of hierarchical mesoporous Mn2O3 nanomaterials with high capacities and cycling stabilities for lithium ion batteries.
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