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- 摘要
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- 实验方案
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Optimal location identification for aggregated charging of electric vehicles in solar photovoltaic powered microgrids with reduced distribution losses
摘要： The battery-powered electric vehicle finds an alternative for fossil fuel-based vehicles in the transportation sector. The charge-discharge power profiles of the battery storage systems (BSS) contribute toward distribution losses, which can be minimized by proper scheduling. Such scheduling gives better results if the charging stations are optimally placed in the solar photovoltaic (PV) powered microgrid. This paper proposes a methodology to identify the optimal location to charge the electric vehicle in the microgrid. The proposed methodology has been developed using particle swarm optimization (PSO)-based optimal power flow (OPF) with an integrated power management (IPM) algorithm. The novelty of the IPM algorithm is the coordinated charging-discharging of the multiple numbers of aBSS of the EVs to reduce the overall distribution losses of the microgrid. The proposed methodology is tested in a standard solar PV powered microgrid network, where the optimal locations to charge the electric vehicles are identified. The daily distribution loss of the network is computed for all possible charging locations of the electric vehicle in the microgrid, and it is found that the distribution loss is minimum for the identified optimal locations. Also, to evaluate the effectiveness of the proposed methodology, the distribution loss analysis is carried out for three test cases; i) un-optimized power flow, ii) PSO based-OPF, and iii) PSO-based OPF with IPM. The case study shows that the PSO-based OPF gives 84% reduction in daily distribution loss compared to the conventional un-optimized power flow test case. The daily distribution loss is further reduced by 8% by incorporating the IPM algorithm in the PSO-based OPF. The utility can thereby encourage the electric vehicle (EV) owners to park their EVs at the optimal locations to reduce the distribution losses.
关键词： microgrid,particle swarm optimization,Battery storage systems,renewable generation,electric vehicle,optimal location
更新于2025-09-23 15:21:01
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Energy Payback Time of a Rooftop Photovoltaic System in Greece
摘要： Life Cycle Analysis (LCA) is an important tool to quantitatively assess energy consumption and environmental impact of any product. Current research related to energy consumption in buildings moves towards Nearly Zero Energy Building (NZEB). In such a building, an important issue concerns the energy production by renewable sources, including on-site production. The most feasible way to achieve renewable energy utilization in a building level in Greece is by using rooftop Photovoltaic (PV) systems, also promoted in the last decade by the national legislation concerning energy conservation measures. Apart from cost-related issues and payback times, Embodied Energy (EE) and Embodied CO2 (ECO2) emissions have also to be considered against the anticipated corresponding savings. Using a particular PV system as a case study, its basic constitutive materials are determined and their masses are calculated. Embodied energy values are estimated by using embodied energy coefficients available in the international literature. Considering a specific geographic location in Greece for the building on which the PV is installed, the annual energy generated by the system is estimated based on its performance data and curves. The Energy and CO2 Payback Times (EPBT and CO2PBT) are estimated and assessed, as well as future work is suggested.
关键词： Photovoltaic systems,CO2 Payback Time,Embodied CO2,Energy Payback Time,Life Cycle Analysis,Nearly Zero Energy Building,Embodied Energy
更新于2025-09-23 15:21:01
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Resonant wavelength thermal stability of fiber Bragg gratings produced by a femtosecond laser
摘要： In this paper, a new ordinary differential equation numerical integration method is successfully applied to various mathematical branches such as partial differential equation (PDE) boundary problems, PDE initial-boundary problems, tough nonlinear equations, and so forth. The new method does not use Jacobian, so it can handle very large systems, say the dimension N = 1 000 000, or even larger. In addition, we give a very simple accelerating convergence approach for the linear algebraic equations arising from linear PDE boundary problems. All the numerical results show that the new method is very promising for super large scale systems.
关键词： nonlinear equations,parallel computation,GMRES(m),ODE method,linear equations,Super large scale systems,PDE boundary problem,inexact Newton method,numerical solution
更新于2025-09-23 15:21:01
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A year-round study of a photovoltaic thermal system integrated with phase change material in Shanghai using transient model
摘要： In the study, the daily and monthly performance of a photovoltaic thermal system integrated with phase change material is investigated in Shanghai, China. A three-dimensional model of photovoltaic thermal system integrated with phase change material system is developed and numerically simulated. Water is considered as working fluid, and the fluid flow regime is laminar and incompressible. Both quasi-steady and transient models are compared together, and the transient model is selected because of its higher accuracy. Validation analysis is performed on the numerical model to show the reasonable agreement of current research compared to some other research. After obtaining the suitable operating time for the system, the performance of the system is studied from both energy and exergy viewpoints during the year. An environmental analysis is also conducted to show the annul carbon dioxide mitigation potential. The results show that July is the best month for operating of the system in shanghai with an operating time period of 13.5 h per day on average, while November, December, and January have the lowest operating time period. The percentage of melted phase change material in January, February, March, November and December is zero which means that the melting process does not occur in these months, due to the low ambient temperature and incident solar radiation in Shanghai. Though the overall energy efficiency of the system is higher in summer, the overall exergy efficiency is lower in this season.
关键词： Quasi-steady and transient models,Environmental analysis,Daily and monthly analysis,Energy and exergy analysis,PVT systems
更新于2025-09-23 15:21:01
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Microfluidic approach for controlled ultraviolet treatment of colored and fluorescent dissolved organic matter
摘要： Using microfluidic systems to address the optical properties of Colored and Fluorescent Dissolved Organic Matter (CDOM/FDOM) offers new ways for researching its interactions with the environment, and its response to rapid, as well as extreme, changes of abiotic conditions. Here we present a microfluidic device with an Ultraviolet (UV) component. The manufactured microfluidic device consists of passing a dissolved organic matter sample through a microchannel applying a combination of treatments using different UV wavelengths and exposure times. Here we test the workability of the microdevice by analyzing the effect of UV light on CDOM and FDOM, using as irradiations UVA and UVB to incite photodegradation, over different times. We then compare the absorbance and fluorescence, measured from both treated and non-treated samples. The analysis of the measurements is done by the calculation of the slope ratio, as indicative of molecular weight and dissolved organic carbon, besides the fluorescence humification index (HIX) as an overview of the difference between treated and non-treated of the excitation-emission matrices (EEMs). Our results show the efficiency of the microdevice by demonstrating a direct relation of degradation degree with exposure time. FDOM exposure to UVB shows a possible relation to humic-like fluorophores intensity, shown in HIX and the overview difference. Furthermore, the changes showed in the slope ratio demonstrate photodegradation in all treatments, with UVB exhibiting an increased influence. The combination of microfluidic sample treatment within in situ applications of optical sensors will enhance our capacities in addressing biogeochemical processes in the marine environment, which were not accessible with conventional bulk methods.
关键词： aquatic systems,CDOM,Slopes,FDOM,Microfluidics,EEMS,HIX
更新于2025-09-23 15:21:01
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Switchable All-Optical Flip-Flop and Inverter Operations in Quantum Well Microring Laser
摘要： In this paper, distributed time-varying formation (TVF) control problems for general linear swarm systems with switching interaction topologies are investigated using an adaptive dynamic protocol. First, a TVF control protocol for switching interaction topologies is constructed using the states of neighboring agents. In the protocol, an adaptive controller that employs gain scheduling technique is provided to estimate the coupling weights among agents. Compared with the previous studies on formation control, the desired formation can be specified by piecewise continuously time-varying differentiable vectors, the interaction topology can be switching, and the disadvantage of requiring global information of the interaction topologies is removed in this paper. Then, an algorithm including a feasible formation condition is proposed to determine the gain matrices of the distributed adaptive formation protocol by solving a linear matrix inequality for swarm systems with switching interaction topologies. Moreover, under the designed distributed adaptive formation protocol, sufficient condition for general linear swarm systems with switching interaction topologies to achieve the given TVF is derived using the Lyapunov theory. Finally, numerical simulations are presented to demonstrate the obtained results.
关键词： general linear dynamics,Distributed adaptive protocol,time-varying formation,swarm systems,switching interaction topology
更新于2025-09-23 15:21:01
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[IEEE 2018 International Conference on Information and Telecommunication Technologies and Radio Electronics (UkrMiCo) - Odessa, Ukraine (2018.9.10-2018.9.14)] 2018 International Conference on Information and Telecommunication Technologies and Radio Electronics (UkrMiCo) - Spatial-Energy Characteristics of Focused Modes of Metallic Terahertz Laser Resonator
摘要： Cellular networks are currently experiencing a tremendous growth of data traffic. To cope with this demand, a close cooperation between academic researchers and industry/standardization experts is necessary, which hardly exists in practice. In this paper, we try to bridge this gap between researchers and engineers by providing a review of current standard-related research efforts in wireless communication systems. Furthermore, we give an overview about our attempt in facilitating the exchange of information and results between researchers and engineers, via a common simulation platform for 3GPP long term evolution (LTE) and a corresponding webforum for discussion. Often, especially in signal processing, reproducing results of other researcher is a tedious task, because assumptions and parameters are not clearly specified, which hamper the consideration of the state-of-the-art research in the standardization process. Also, practical constraints, impairments imposed by technological restrictions and well-known physical phenomena, e.g., signaling overhead, synchronization issues, channel fading, are often disregarded by researchers, because of simplicity and mathematical tractability. Hence, evaluating the relevance of research results under practical conditions is often difficult. To circumvent these problems, we developed a standard-compliant open-source simulation platform for LTE that enables reproducible research in a well-defined environment. We demonstrate that innovative research under the confined framework of a real-world standard is possible, sometimes even encouraged. With examples of our research work, we investigate on the potential of several important research areas under typical practical conditions, and highlight consistencies as well as differences between theory and practice.
关键词： MIMO,pilot power allocation,LTE,Heterogeneous networks,distributed antenna systems,reproducible research,frequency synchronization,multiuser gains
更新于2025-09-23 15:21:01
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High-Speed Neuromorphic Reservoir Computing Based on a Semiconductor Nanolaser with Optical Feedback Under Electrical Modulation
摘要： A high-speed neuromorphic reservoir computing system based on a semiconductor nanolaser with optical feedback (SNL-based RC) under electrical modulation is proposed for the first time and demonstrated numerically. A Santa-Fe chaotic time series prediction task is employed to quantify the prediction performance of the SNL-based RC system. The effects of the Purcell cavity-enhanced spontaneous emission factor F and the spontaneous emission coupling factor β on the proposed RC system are analyzed extensively. It is found that, in general, increased F and β extend the range of good prediction performance of the SNL-based RC system. Moreover, the influences of bias current and feedback phase are also considered. Due to the ultra-short photon lifetime in SNL, the information processing rate of the SNL-based RC system reaches 10Gpbs. The proposed high-speed SNL-based RC system in this paper provides theoretical guidelines for the design of RC-based integrated neuromorphic photonic systems.
关键词： spontaneous emission coupling factor,Purcell factor,reservoir computing,Semiconductor nanolaser,delay systems
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) - Adaptive Voltage Regulation for Solar Power Inverters on Distribution Systems
摘要： By means of time-series power flow, this paper compares the performance of several reactive power control modes allowed in the new IEEE 1547. It is shown that voltage-reactive power mode (sometimes called volt-var) should be considered for a universal default setting, with no deadband, the highest allowed gain of 22 for Category B inverters, and a gain of 12.5 for Category A inverters. The reference voltage should adapt to the system voltage, with a 300s time constant.
关键词： Photovoltaic systems,smart grids,inverters,automatic voltage control,distributed power generation
更新于2025-09-23 15:21:01
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Retarding System of the Diafraged Rectangular Waveguide Type
摘要： In this paper, we propose fast and sufficiently accurate models for retarding systems (RS) such as double-shifted combs in a rectangular screen and RS of the looping waveguide type based on the diaphragm conductivity calculation in a rectangular waveguide (RW). The conductivity of the capacitive diaphragm in the RW is obtained for electric and magnetic wide walls. Multimode models based on functionals of electric and magnetic types are also proposed. The models facilitate correct account of losses. The dispersion of a double comb and looping waveguide with infinitely thin walls is calculated.
关键词： rectangular waveguide,multimode models,diaphragm conductivity,retarding systems,dispersion
更新于2025-09-23 15:21:01