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Optimal placement of distributed generation units in distribution systems via an enhanced multi-objective particle swarm optimization algorithm

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Journal of Zhejiang University-Science C(Computers and Electronics) 2014年第4期15卷 300-311页

作者： Shan CHENG Min-you CHEN Rong-jong WAI Fang-zong WANG College of Electrical engineering and new energy China Three Gorges University State Key Laboratory of power transmission Equipment & system Security and new technology Department of Electrical engineering and Fuel Cell center Yuan Ze University

This paper deals with the optimal placement of distributed generation(DG) units in distribution systems via an enhanced multi-objective particle swarm optimization(EMOPSO) algorithm. To pursue a better simulation of the reality and provide the designer with diverse alternative options, a multi-objective optimization model with technical and operational constraints is constructed to minimize the total power loss and the voltage fluctuation of the power system simultaneously. To enhance the convergence of MOPSO, special techniques including a dynamic inertia weight and acceleration coefficients have been integrated as well as a mutation operator. Besides, to promote the diversity of Pareto-optimal solutions, an improved non-dominated crowding distance sorting technique has been introduced and applied to the selection of particles for the next iteration. After verifying its effectiveness and competitiveness with a set of well-known benchmark functions, the EMOPSO algorithm is employed to achieve the optimal placement of DG units in the IEEE 33-bus system. Simulation results indicate that the EMOPSO algorithm enables the identification of a set of Pareto-optimal solutions with good tradeoff between power loss and voltage stability. Compared with other representative methods, the present results reveal the advantages of optimizing capacities and locations of DG units simultaneously, and exemplify the validity of the EMOPSO algorithm applied for optimally placing DG units.

关键词： Distributed generation Multi-objective particle swarm optimization Optimal placement Voltage stability index power loss

Weighted sum power maximization for STAR-RIS-aided SWIPT systems with nonlinear energy harvesting

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Science China(Information Sciences) 2024年

作者： Weiping SHI Cunhua PAN Feng SHU Yongpeng WU Jiangzhou WANG Yongqiang BAO Jin TIAN School of Network and Communication Nanjing Vocational College of Information Technology National Mobile Communications research Laboratory Southeast University School of Information and Communication engineering Hainan University School of Electronic and Optical engineering Nanjing University of Science and Technology Shanghai Key Laboratory of Navigation and Location Based Services Shanghai Jiao Tong University School of engineering University of Kent School of Information and Communication engineering Nanjing Institute of Technology engineering School of Networks and Telecommunications Jinling Institute of Technology

The conventional reconfigurable intelligent surface (RIS) is limited to reflecting incident signals,thereby imposing constraints on the placement of the transmitter and receiver, which hinders achieving comprehensive signal coverage across an entire area. This paper investigates a simultaneously transmitting and reflecting (STAR)-RIS-aided simultaneous wireless information and power transfer (SWIPT) system with a nonlinear energy harvesting model under three different RIS transmission protocols:energy splitting (ES),time switching (TS), and mode switching (MS). The objective of this paper is to maximize the weighted sum power (WSP) of all energy harvesting receivers (EHRs) while ensuring fairness in the collected power among them. This is achieved by jointly optimizing the transmit beamforming at the base station (BS)and the transmission and reflection coefficients at the STAR-RIS, subject to rate constraints for information decoding receivers (IDRs), transmit power constraint at the BS, and coefficient constraints of each element at the STAR-RIS corresponding to the three protocols. Solving this optimization problem poses challenges because of the complicated objective function and numerous coupled optimization variables of the ES STARRIS. To address this complexity, an efficient alternating optimization (AO) approach is proposed as an iterative solution method that achieves suboptimal results. The AO algorithm is then extended to MS STAR-RIS and TS STAR-RIS. Specifically, for MS STRA-RIS, binary constraints in the STAR-RIS coefficient optimization subproblem are handled using the first-order approximation technique along with the penalty function method. For TS STAR-RIS, apart from optimizing BS transmit beamforming and STAR-RIS coefficients subproblems, the transmission and reflection time allocation of STAR-RIS also needs *** findings demonstrate that compared to conventional RIS-aided systems, utilizing three different protocols in a STAR-RIS

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Anti-Overturning Fully Symmetrical Triboelectric Nanogenerator Based on an Elliptic Cylindrical Structure for All-Weather Blue energy Harvesting

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Nano-Micro Letters 2022年第7期14卷 342-353页

作者： Dujuan Tan Qixuan Zeng Xue Wang Songlei Yuan Yanlin Luo Xiaofang Zhang Liming Tan Chenguo Hu Guanlin Liu Department of Applied Physics State Key Laboratory of Power Transmission Equipment&System Security and New TechnologyChongqing UniversityChongqing 400044People’s Republic of China center On Nanoenergy research School of Physical Science and TechnologyGuangxi UniversityNanningGuangxi 530004People’s Republic of China

Triboelectric nanogenerators(TENGs) have shown promising potential for large-scale blue energy harvesting. However, the lack of reasonable designs has largely hindered TENG from harvesting energy from both rough and tranquil seas. Herein, a fully symmetrical triboelectric nanogenerator based on an elliptical cylindrical structure(EC-TENG) is proposed for all-weather blue energy harvesting. The novel elliptical cylindrical shell provides a unique selfstability, high sensitivity to wave triggering, and most importantly, an anti-overturning capability for the EC-TENG. Moreover, benefiting from its internal symmetrical design, the EC-TENG can produce energy normally, even if it was overturned under a rude oscillation in the rough seas, which distinguishes this work from previous reported TENGs. The working mechanism and output performance are systematically studied. The as-fabricated EC-TENG is capable of lighting 400 light-emitting diodes and driving small electronics. More than that, an automatic monitoring system powered by the EC-TENG can also monitor the water level in real-time and provide an alarm if necessary. This work presents an innovative and reliable approach toward all-weather wave energy harvesting in actual marine environments.

关键词： Anti-overturning Fully symmetrical Elliptic cylindrical Triboelectric nanogenerator Wave energy

Miura folding based charge-excitation triboelectric nanogenerator for portable power supply

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Nano research 2021年第11期14卷 4204-4210页

作者： Gui Li Guanlin Liu Wencong He Li Long Bangxing Li Zhao Wang Qian Tang Wenlin Liu Chenguo Hu Department of Applied Physics Chongqing Key Laboratory of Soft Condensed Matter Physics and Smart MaterialsState Key Laboratory of Power Transmission Equipment&System Security and New TechnologyChongqing UniversityChongqing400044China center on Nanoenergy research School of Physical Science and TechnologyGuangxi UniversityNanning530004China

Miniaturized mobile electronic devices have aroused great attention due to their convenience to daily life. However, they still face a problem that power supply from the conventional cell needs to be regularly charged or replaced. Portable electricity supply collecting energy from environment is highly desired. Herein, a highly flexible and stretchable Miura folding based triboelectric nanogenerator (MF-TENG) is prepared by using flexible polyethylene terephthalate (PET) as a folding substrate with a double working side design, specifically one side as the main TENG (M-TENG) and other side as the excitation TENG (E-TENG). The E-TENG supplements charge to M-TENG by a half-wave rectifier circuit. This design increases the TENG working area and reduces its volume. The output performance of the TENG based on Miura folding with charge excitation called MF-CE-TENG is greatly boosted. The optimal output charge and maximum peak power of MF-CE-TENG achieves 1.54 µC and 5.17 mW at 1 Hz, respectively, which is 4.61 and 10.55 times as much as that of MF-TENG without charge excitation. To demonstrate its applications, the MF-CE-TENG is used to light up 456 LEDs brightly and charge a 100 µF capacitor to 6.07 V in 5 min. A calculator and a temperature-humidity sensor work normally powered by MF-CE-TENG with an energy management module. This work provides a new strategy to enhance the output energy of Miura folding TENG by applying a charge excitation mode for the first time, which might be an effective approach to be used in other TENGs.

关键词： Miura folding triboelectric nanogenerator charge excitation half-wave rectifier circuit

A DFT study on PtMo resistance to SO_2 poisoning

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Science China Chemistry 2013年第7期56卷 1004-1008页

作者： XIA MeiRong LIU Ying LI Li XIONG Kun QI XueQiang YANG LinJiang HU BaoShan XUE Yun WEI ZiDong The State Key Laboratory of power transmission Equipment & system Security and new technology School of Chemistry and Chemical Engineering Chongqing University

Pt is a catalyst in proton exchange membrane fuel cell （PEMFC）, and its activity will be degraded in the air due to the exist- ence of SOx impurities. On strategy is introducing of Mo into the Pt catalyst because it can improve the SOx-tolerance capacity. Based on the aforementioned phenomenon, a density function theory （DFT） study on SOx adsorbed on Pt（111） and PtMo（111） was performed to enhance Pt catalytic activity. The adsorption energy of adsorbed species, the net change, partial density of state （PDOS）, and d-band center were calculated and analyzed comparatively. The results show that the presence of Mo-atom weakens the S-Pt bond strength and reduces the adsorption energies for SO2, S and SO3 on PtMo（111）. Moreover, the Mo atom weakens the effects of SO2 on the PtMo（lll） electronic structure and makes the catalyst maintains its original electronic structure after SO2 adsorption as compared with Pt（111）.

关键词： density functional theory SO2 Pt PtMo partial density of states fuel cells electrocatalysis

In-situ TEM observation of the evolution of helium bubbles in Mo during He^(+)irradiation and post-irradiation annealing

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Chinese Physics B 2021年第8期30卷 102-112页

作者： Yi-Peng Li Guang Ran Xin-Yi Liu Xi Qiu Qing Han Wen-Jie Li Yi-Jia Guo College of energy Xiamen UniversityXiamen 361102China Fujian research center for Nuclear engineering Xiamen 361102China Science and technology on Reactor system Design technology Laboratory Nuclear Power Institute of ChinaChengdu 610213China

The evolution of helium bubbles in purity Mo was investigated by in-situ transmission electron microscopy(TEM)during 30 keV He^(+)irradiation(at 673 K and 1173 K)and post-irradiation annealing(after 30 keV He^(+)irradiation with the fluence of 5.74×10^(16)He^(+)/cm^(2)at 673 K).Both He^(+)irradiation and subsequently annealing induced the initiation,aggregation,and growth of helium *** had a significant effect on the initiation and evolution of helium *** higher the irradiation temperature was,the larger the bubble size at the same irradiation fluence would *** 1173 K irradiation,helium bubbles nucleated and grew preferentially at grain boundaries and showed super large size,which would induce the formation of *** the same time,the geometry of helium bubbles changed from sphericity to *** polyhedral bubbles preferred to grow in the shape bounded by{100}*** statistical analysis of the characteristic parameters of helium bubbles,the functions between the average size,number density of helium bubbles,swelling rate and irradiation damage were ***,an empirical formula for calculating the size of helium bubbles during the annealing was also provided.

关键词： helium bubbles in-situ TEM observation ion irradiation annealing molybdenum

In situ induced cation-vacancies in metal sulfides as dynamic electrocatalyst accelerating polysulfides conversion for Li-S battery

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Journal of energy Chemistry 2022年第12期75卷 74-82,I0003页

作者： Rongrong Li Hao Sun Caiyun Chang Yuan Yao Xiong Pu Wenjie Mai Siyuan Laboratory Guangdong Provincial Engineering Technology Research Center of Vacuum Coating Technologies and New Energy MaterialsDepartment of PhysicsJinan UniversityGuangzhou 510632GuangdongChina CAS center for Excellence in Nanoscience Beijing Key Laboratory of Micro-Nano Energy and SensorBeijing Institute of Nanoenergy and NanosystemsChinese Academy of SciencesBeijing 101400China State Key Laboratory of power transmission Equipment and system Security and new technology School of Electrical EngineeringChongqing UniversityChongqing 400044China center of Materials Science and Optoelectronics engineering University of Chinese Academy of SciencesBeijing 100049China

Cation vacancy engineering is considered to be one of the effective methods to solve the issues of shuttling and sluggish redox kinetics of Li PSs owing to the intrinsic tunability of electronic ***,cation vacancies are few studied in the Li-S realm due to their complex and rigid preparation *** this work,one-step pyrolysis is reported to in situ introduce Fe-vacancies into iron sulfide(Fe_(0.96)S)as a sulfur *** this host structure,Fe_(0.96)S is first employed as an adsorbent and catalyst in Li-S *** the carbonization process,a tight contact structure of Fe_(0.96)S crystal and carbon network(Fe_(0.96)S@C)is in situ constructed,and the carbon layer as a conductor provides smooth electrons transfer pathways for redox ***,due to the introduction of Fe-vacancies in Fe S crystal,the adsorption capability and catalytic effect for Li PSs have been substantially ***,the presence of Fe_(0.96)S crystal favors the mobility of electron and diffusion of Li+,which is revealed by the experiments and theoretical *** synergy respective advantages effect of Fe_(0.96)S and carbon,the Fe_(0.96)S@C-S cathode delivers high-rate capability at 5.0 C and stable long-life *** under a high sulfur loading of 3.5 mg/cm^(2),the durable cyclic stability is still exhibited with the capacity retention of 93%over 400 cycles at 1.0 C,and the coulombic efficiency is≥98%.Noting that this strategy greatly simplifies the synthetic process of currently known cation-vacancy materials and furnishes a universal mentality for designing both divinable and astonishing new cation-vacancy materials.

关键词： Cation vacancy Fe_(0.96)S@C structure Catalytic conversion Lithium-sulfur battery

DFT study on ORR catalyzed by bimetallic Pt-skin metals over substrates of Ir,Pd and Au

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纳米材料科学:英文版 2023年第3期5卷 287-292页

作者： Xueqiang Qi Tingting Yang Pingbo Li Zidong Wei College of Chemistry and Chemical engineering Chongqing University of TechnologyChongqing400054China The State Key Laboratory of power transmission Equipment&system Security and new technology College of Chemistry and Chemical EngineeringChongqing UniversityChongqing400044China

Bimetallic Pt-skin catalyst is a class of near-surface alloy(NSA)that owns a high degree of control over ***,density functional theory(DFT)is used to calculate the energetics of oxygen reduction reaction(ORR)on Pt-skin over Ir,Pd and Au substrates.A Brønsted-Evans-Polanyi(BEP)relationship can be determined for the oxygen molecule *** binding energy of both atomic oxygen and hydroxyl radical is found to correlate well with the d band center of Pt-skin *** catalytic activities show the volcano relationship as the positions of each substrate in the periodic *** effect of surface strain,band structure and charge transfer on the d band center is well studied,and it can be found that the surface strain effect plays a dominant role for all Pt-skin *** substrate makes the d band center of Pt-skin go far away from the Fermi level,while Au substrate makes it move towards the Fermi *** different from both Ir and Au,Pd substrate makes the d band center of Pt-skin comparable with the monometallic Pt.

关键词： ORR DFT Pt-skin Catalysts

Resource Allocation for IRS Assistedmm Wave Wireless powered Sensor Networks with User Cooperation

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工程与科学中的计算机建模(英文) 2024年第1期138卷 663-677页

作者： Yonghui Lin Zhengyu Zhu Network center Zhengzhou UniversityZhengzhou450001China School of Electrical and Information engineering Zhengzhou UniversityZhengzhou450001China

In this paper,we investigate IRS-aided user cooperation(UC)scheme in millimeter wave(mmWave)wirelesspowered sensor networks(WPSN),where two single-antenna users are wireless powered in the wireless energy transfer(WET)phase first and then cooperatively transmit information to a hybrid access point(AP)in the wireless information transmission(WIT)phase,following which the IRS is deployed to enhance the system performance of theWET *** maximized the weighted sum-rate problem by jointly optimizing the transmit time slots,power allocations,and the phase shifts of the *** to the non-convexity of the original problem,a semidefinite programming relaxation-based approach is proposed to convert the formulated problem to a convex optimization framework,which can obtain the optimal global *** results demonstrate that the weighted sum throughput of the proposed UC scheme outperforms the non-UC scheme whether equipped with IRS or not.

关键词： Intelligent reflecting surface millimeter wave wireless powered sensor networks user cooperation resource allocation