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DC Overvoltage Analysis of GFM-controlled Wind Farm Connected via MMC-HVDC system Caused by Receiving-end AC Faults

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DC Overvoltage Analysis of GFM-controlled Wind Farm Connecte...

International Conference on Power Electronics and Motion control (IPEMC)

作者： Siying Chen Min Cheng Yingbiao Li Jiawei Yu Yihua Zhu Mingkang Wu Jiabing Hu Jianan Yan State Key Laboratory of Advanced Electromagnetic Technology and School of Electrical and Electronic Engineering Huazhong University of Science and Technology China Yunnan Power Grid China CSG Key Laboratory for Power System Simulation (Electric Power Research Institute China Southern Power Grid) State Key Laboratory of HVDC (Electric Power Research Institute China Southern Power Grid) National Energy Power Grid Technology R&D Centre Guangdong Provincial Key Laboratory of Intelligent Operation and Control for New Energy Power System China

ISBN: (数字)9798350351330

ISBN: (纸本)9798350351347

DC overvoltage occurs when short circuit fault exists at the receiving-end and is harmful to the safety of the system where wind farms are connected to the grid through high-voltage direct current (HVDC) transmission based on the modular multilevel converter (MMC). To address this issue, this paper first analyzed the mechanism of the DC overvoltage and innovatively proposed a strategy in which grid-forming-controlled wind farms are integrated into the AC grid through MMC-HVDC, whose sending-end applies grid-following control and constant DC voltage control. However, secondary DC overvoltage appears during the fault recovery stage and is mainly caused by the saturation of the PI controller of constant active power control. Simulations are carried out on a test with MATLAB/Simulink, and results verify the efficacy of the proposed methods in suppressing DC overvoltage that appeared during receiving-end faults and their recovery stage.

关键词： PI control Simulation Power control Wind farms Robustness Wind turbines Safety

Impulsive Formation control of Nonlinear Leader-Following Multi-agent systems with Input Saturation*

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Impulsive Formation Control of Nonlinear Leader-Following Mu...

Industrial Cyber-Physical systems (ICPS)

作者： Ni Zhang Xiaowei Jiang Xianhe Zhang Le You School of Automation China University of Geosciences Wuhan China Hubei Key Laboratory of Advanced Control and Intelligent Automation of Complex Systems Wuhan China Engineering Research Center of Intelligent Technology for Geo-Exploration Ministry of Education Wuhan China Key Laboratory of System Control and Information Processing Ministry of Education Shanghai China School of Electrical Engineering and Automation Hubei Normal University Huangshi China

Leader-following formation analysis problem for a second-order nonlinear multi-agent system(MAS) with input saturation is investigated in this paper. And the impulsive formation control algorithm is introduced in the designed protocol which only works at the impulse times. Owing to the real-world limited communication channels, input saturation is considered in the impulsive controller. Furthermore, based on Lyapunov stability theories, Kronecker properties, eigenvalue and so on, some sufficient conditions that guarantee the leader-following consensus of MAS are obtained. Lastly, several simulations are worked out to verify the correctness and effectiveness of the theoretical results.

关键词： Sufficient conditions Protocols Simulation Communication channels Cyber-physical systems control systems Formation control

Application of the High-Q Bouncing Ball Model Based on Fabry-Pérot Cavity for Alcohol Gas Concentration Detection

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SSRN 2023年

作者： Sang, Luxiao Wang, Teng Zhao, Biao Ding, Jinyu Jian, Aoqun Sang, Shengbo Shanxi Key Laboratory of Micro Nano Sensors & Artificial Intelligence Perception College of Electronic Information and Optical Engineering Taiyuan University of Technology Taiyuan030024 China Key Lab of Advanced Transducers and Intelligent Control System Ministry of Education Taiyuan University of Technology Taiyuan030024 China Shanxi Research Institute of 6D Artificial Intelligence Biomedical Science Taiyuan030031 China

This paper presents a method to enhance the Q factor of Fabry-Pérot cavities using a vertical dielectric interface (DI) made of silicon and air, which generates a bouncing ball model. The method is applied to detect alcohol gas concentrations with high resolution. Specifically, we introduce a 450 µm-thick silicon wafer into the Fabry-Pérot (FP) cavity, where it is positioned at an angle of inclination. This addition considerably augments the light-matter interaction, effectively confining the light within the cavity. The Q factor of the FP cavity with DI is always higher than that of the open FP cavity in the inclination angle range of 0 to 1°. Moreover, the effective mode area of the FP cavity with DI is smaller. Furthermore, the FP cavity with DI reduces the effective mode area and diminishes the lateral walk-off loss experienced in the open FP cavity. Finally, we experimentally verified the effectiveness of this method by detecting alcohol gas concentrations ranging from 28.5 ppm to 142.5 ppm and achieving a Q factor improvement from 5.9×104 to 1.2×105. The system sensitivity was calculated to be 0.5294 pm/ppm, and the resolution obtained was 28.5 ppm. © 2023, The Authors. All rights reserved.

关键词： Silicon wafers

Polarization-Induced Proton Adsorption and Charge Separation in Pyrene-Based Conjugated Microporous Polymers Via Substituent Regulation for Efficient Photocatalytic Hydrogen Evolution

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SSRN 2023年

作者： Ren, Runtang Jiao, Zhengxu Li, Zhanfeng Tian, Yue Liu, Baoyou Yue, Gang Key Laboratory of Advanced Transducers and Intelligent Control System Ministry of Education and Shanxi Province Taiyuan University of Technology Taiyuan030024 China Institute of Carbon Materials College of Materials Science and Engineering Taiyuan University of Technology Taiyuan030024 China Technology Innovation Center Ningxia Sinostar Display Material Co. Ltd. Yinchuan750003 China

Constructing photocatalysts with efficient light-harvesting abilities and charge separation properties is highly promising but still challenging for boosting photocatalytic hydrogen evolution from water. Herein, we report a simple and general polarization strategy through substituent regulation such as fluorination, chlorination and cyanation, to promote the photon capture and charge separation and unveil the latent structure–property–activity relationship in pyrene-based conjugated microporous polymers (CMPs). Notably, the introduction of fluorine, chlorine and cyano substituents onto the well-known full donor pyrene-benzene-based CMP network (Py-B) could induce a strong dipole along C–F/–Cl/–CN bonds and the backbone local polarization enhancement due to their strong electron-withdrawing ability, which afforded CMPs have a variety of superior effects such as narrowing band gaps, expanding optical absorption, improving interfacial wettability and solid-state morphology, and promoting charge separation inside organic photocatalysts. As a result, 1.73/2.50/4.69-fold increases of the hydrogen evolution rates of the –F/–Cl/–CN modified CMPs under visible light (λ > 420 nm) irradiation without Pt co-catalysts can be obtained in comparison with the counterpart Py-B (28.5/41.3/77.4 mmol g−1 h−1 vs 16.5 mmol g−1 h−1). Impressively, we find that the photocatalytic performance of this series of photocatalysts is linearly related to the dipole moment of polymers. Our studies reveal that the backbone local polarization enhancement induced by the substituent regulation could achieve high-performance organic photocatalysts toward solar-to-chemical energy conversion. © 2023, The Authors. All rights reserved.

关键词： Polarization

Uv-Ozone Treated Ti3c2tx-Mxene Nanosheets as Hole Injection Layer for Organic Light-Emitting Diodes

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SSRN 2022年

作者： Lu, Qiqing Wang, Jingkun Miao, Yanqin Guo, Yuanyuan Wang, Guoliang Dong, Jianhua Zhao, Min Wang, Hua Key Laboratory of Interface Science and Engineering in Advanced Materials Ministry of Education Taiyuan University of Technology Taiyuan030024 China Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering Taiyuan030024 China Key Laboratory of Advanced Transducers and Intelligent Control System Ministry of Education Taiyuan University of Technology Taiyuan030024 China College of Textile Engineering Taiyuan University of Technology Jinzhong030600 China

In this work, we successfully synthesized Ti3C2Tx-MXene nanosheets with a lateral dimension of 1~2 um by using wet-chemical etchant and sonication-assisted liquid-phase exfoliation method. After UV-ozone treatment, the work function for Ti3C2Tx-MXene nanosheets was adjusted to 5.14 eV well matching to indium tin oxide (ITO) anode (4.80 eV). Using Ti3C2Tx-MXene nanosheets as hole injection layer (HIL), Ir(ppy)3-based green organic light-emitting diodes (OLEDs) were fabricated, and the resulting devices exhibit a low turn-on voltage of 3.0 V and the high current efficiency, power efficiency and external quantum efficiency of 72.79 cd/A, 54.44 lm/W and 20.34%, which are obviously better than these of 67.38 cd/A, 50.38 lm/W and 18.65% for PEDOT:PSS-based reference device. Further, FIrpic- and Ir(pq)2acac-based blue and red OLEDs with Ti3C2Tx-MXene nanosheets HIL were demonstrated, which also show the significantly improved device efficiency of 44.56 cd/A, 32.44 lm/W and 22.07% for blue device and 39.17 cd/A, 38.54 lm/W and 21.90% for red device than these for corresponding PEDOT:PSS-based devices, proving the universal applicability of Ti3C2Tx-MXene nanosheets as HIL in OLEDs. The higher performance for Ti3C2Tx-MXene nanosheets-based devices can be attributed to the appropriate work function, high transmittance, high carrier mobility and good film forming property for Ti3C2Tx-MXene nanosheets. This is the first report about the MXene using as HIL in OLEDs, which opens up a new way to develop high-performance holes injection materials for solution-processed OLEDs. © 2022, The Authors. All rights reserved.

关键词： Organic light emitting diodes (OLED)

A Graphical Pressure Sensor Array With Multilayered Structure: Written Through Graphene Ink on Cellulose Paper Substrate

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Research Square

Research Square 2021年

作者： Ji, Chao Zhang, Qiang Li, Qiang Pei, Zhen Zhao, Dong Yuan, Zhongyun Wang, Jie Zhang, Wendong Sang, Shengbo MicroNano System Research Center Key Laboratory of Advanced Transducers and Intelligent Control System of the Ministry of Education and Shanxi Province College of Information and Computer Taiyuan University of Technology Shanxi Taiyuan030024 China

Paper based flexible pressure sensors have received extensive attention due to their recoverability and accessibility. In this paper, we proposed graphical pressure sensors array with multilayered structure. A simple writing method was adopted to achieve the adsorption of sensitive materials on the fiber structure of cellulose paper. Pressure sensors with 1, 3, 5 and 7 stacked layers were fabricated and compared, respectively. The results show that the 7-layers sensor combined high sensitivity (44 kPa-1) and fast time response (150 ms). The highly sensitive stacked paper-based sensor array realizes the pressure detection of objects and special-shaped surfaces. A pressure sensor base on commercial corrugated box was also fabricated to compare. The corrugated carton array was made to switch reminder devices for its convenience and accessibility. Since there are many scenarios that require a safe distance, especially under the influence of the COVID-19, the writable paper-based sensor array was used to realize graphical distance perception and warning. © 2021, CC BY.

关键词： Pressure sensors

UWB Non-Line-of-Sight Recognition and Suppression Methodology

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UWB Non-Line-of-Sight Recognition and Suppression Methodolog...

International Conference on Communication Software and Networks, ICCSN

作者： Zhengshuai Ni Haibo Zhou Guozheng Zhang Wangbei Xu National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin China Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University Tianjin China

Ultra-Wide Band (UWB) positioning system has become the main research object in indoor positioning field due to its superior positioning performance. Accuracy at the scale of centimeters is achievable in an ideal positioning scenario. Nonetheless, the intricate and changeable indoor surroundings may cause UWB signals to propagate beyond the line-of-sight (LOS) and weaken in signal strength, resulting in a considerable reduction in the precision of positioning. In this paper, methods for identifying non-line-of-sight (NLOS) errors, alleviating NLOS errors, and integrating multi-sensor information are analyzed and studied to provide reference for improving the NLOS positioning accuracy of UWB.

关键词：

Logistics Demand Forecasting and Scheduling Optimization Using K-Means Clustering and Deep Q-Network

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Logistics Demand Forecasting and Scheduling Optimization Usi...

Electronics, Energy systems and Power Engineering (EESPE), IEEE International Conference on

作者： Kun Liang Hang Zhang School of Management Tianjin University of Technology Tianjin China Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin China

ISBN: (数字)9798350389579

ISBN: (纸本)9798350389586

With the rapid development of e-commerce and supply chain management, logistics demand forecasting and scheduling optimization have become key links in improving logistics efficiency and service quality. To meet this challenge, this paper proposes a logistics demand forecasting and scheduling optimization method that combines K-Means clustering with deep Q network (DQN). Cluster analysis is used to reduce data complexity, and deep reinforcement learning is used to achieve intelligent scheduling. First, the background, challenges and research motivation of logistics demand forecasting and scheduling optimization are introduced. Secondly, the research results in related fields are reviewed, and the shortcomings of current research are pointed out. Then, the K-Means clustering algorithm, deep $\mathbf{Q}$ network theory and specific models of logistics demand prediction and scheduling optimization are elaborated. Then, the performance of the proposed method is designed and tested. The experimental results show that the proposed method can significantly improve the accuracy of logistics demand prediction, up to 0.93, optimize scheduling strategies, reduce logistics costs, and improve customer satisfaction.

关键词： Training Accuracy Costs Computational modeling Customer satisfaction Demand forecasting Clustering algorithms Predictive models Scheduling Logistics

Black Phosphorus-Organic Framework-Derived Pei/Peg Nanohybrid Prepared by a One-Pot Method for a Wide Detection Range Co2 Gas Sensor

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SSRN 2022年

作者： Liu, Lulu Sang, Shengbo Han, Dan Liu, Zhihua Han, Xiaomei Li, Donghui Chen, Yi Liu, Dongming Liu, Xiaoru Zhuo, Kai Cheng, Yongqiang Yang, Kun Shanxi Key Laboratory of Micro Nano Sensors & Artificial Intelligence Perception College of Information and Computer Taiyuan University of Technology Taiyuan030024 China Key Lab of Advanced Transducers and Intelligent Control System of the Ministry of Education Taiyuan University of Technology Taiyuan030024 China Key Laboratory of Interface Science and Engineering in Advanced Materials Taiyuan University of Technology Ministry of Education Taiyuan030024 China

In this paper, we report a hybrid PEI/PEG-BP sensor (composite material of black phosphorus-organic framework-derived PEI/PEG nanohybrid) prepared by a one-pot method, in which the existence of PEI/PEG onto BP was confirmed by SEM, EDS, XPS and UPS. The gas sensing properties of the PEI/PEG-BP sensor, including the sensor response, response/recovery times, repeatability, selectivity, and effects of humidity on the sensor, were studied by exposure to several CO 2 gas concentrations ranging from 200 ppm to 300,000 ppm at room temperature (25 ℃). The results show that the PEI/PEG-BP sensor had an extremely wide detection range, with lower and upper detection limits of 200 ppm and 160,000 ppm, respectively. The response of the PEI/PEG-BP sensor to 200 ppm, and 160,000 ppm CO 2 gas at room temperature ( RT ) was 4.48%, and 254.02%, respectively, showing fast response/recovery time, excellent repeatability and high selectivity. The gas-sensing properties of the PEI/PEG-BP sensor are better than BP, PEI, PEG, PEI-BP and PEG-BP sensors. The superior properties of the PEI/PEG-BP sensor can be attributed to the BP framework, porous structure, electron doping, and surface reactive groups such as -NH 2 and -OH. The PEI/PEG-BP sensor, with its excellent gas-sensing performance will help us to further explore the changes of CO 2 concentration in microbial growth systems, natural environments, industrial production and so on. © 2022, The Authors. All rights reserved.

关键词： Carbon dioxide