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Distributed Event-triggered Secondary Control for Average Bus Voltage Regulation and Proportional Load Sharing of DC Microgrid

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Journal of Modern Power Systems and Clean Energy 2022年第3期10卷 678-688页

作者： zhongwen li Zhiping Cheng Jikai Si Shuhui li School of Electrical Engineering Zhengzhou UniversityZhengzhou 450001China Department of Electrical and Computer Engineering The University of AlabamaTuscaloosaAL 35487USA

This paper proposes a novel distributed event-triggered secondary control method to overcome the drawbacks of primary control for direct current(DC)microgrids.With eventtriggered distributed communication,the proposed control method can achieve system-wide control of parallel distrubted generators(DGs)with two main control objectives:①estimate the average bus voltage and regulate it at the nominal value;②achieve accurate current sharing among the DGs in proportion to their power output ratings.Furthermore,the proposed control strategy can be implemented in a distributed way that shares the required tasks among the DGs.Thus,it shows the advantages of being flexible and scalable.Furthermore,this paper proposes a simple event-triggered condition that does not need extra state estimator.Thus,limited communication among neighbors is required only when the event-triggered condition is satisfied,which significantly reduces the communication burden at the cyber layer.

关键词： Direct current(DC)microgrid droop control event-triggered secondary control distributed consensus load sharing

Analysis of multi-center topological domain states in BiFeO_(3)nanodot arrays

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Journal of Advanced Dielectrics 2023年第6期13卷 7-12页

作者： zhongwen li Siyi Zhang Qingsheng li Hao liu Faculty of Mathematics and Physics Huaiyin Institute of Technology Huai’anJiangsu 223003P.R.China

High-density ferroelectric BiFeO_(3)(BFO)nanodot arrays were developed through template-assisted tailoring of epitaxial thin films.By combining piezoresponse force microscopy(PFM)and Kelvin probe force microscopy(KPFM)imaging techniques,we found that oxygen vacancies in nanodot arrays can be transported in the presence of an electric field.Besides triple-center domains,quadruple-center domains with different vertical polarizations were also identified.This was confirmed by combining the measurements of the domain switching and polarization vector distribution.The competition between the accumulation of mobile charges,such as oxygen vacancies,on the interface and the geometric constraints of nanodots led to the formation of these topological domain states.These abnormal multi-center topological defect states pave the way for improving the storage density of ferroelectric memory devices.

关键词： Topological domains oxygen vacancies ferroelectric nanodot

MAS Based Distributed Automatic Generation Control for Cyber-Physical Microgrid System

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IEEE/CAA Journal of Automatica Sinica 2016年第1期3卷 78-89页

作者： zhongwen li Chuanzhi Zang Peng Zeng Haibin Yu Hepeng li Laboratory of Networked Control Systems Shenyang Institute of Automation Chinese Academy of Sciences University of Chinese Academy of Sciences IEEE

The microgrid is a typical cyber-physical microgrid system(CPMS). The physical unconventional distributed generators(DGs) are intermittent and inverter-interfaced which makes them very different to control. The cyber components,such as the embedded computer and communication network,are equipped with DGs, to process and transmit the necessary information for the controllers. In order to ensure system-wide observability, controllability and stabilization for the microgrid,the cyber and physical component need to be integrated. For the physical component of CPMS, the droop-control method is popular as it can be applied in both modes of operation to improve the grid transient performance. Traditional droop control methods have the drawback of the inherent trade-off between power sharing and voltage and frequency regulation. In this paper, the global information(such as the average voltage and the output active power of the microgrid and so on) are acquired distributedly based on multi-agent system(MAS). Based on the global information from cyber components of CPMS, automatic generation control(AGC) and automatic voltage control(AVC)are proposed to deal with the drawback of traditional droop control. Simulation studies in PSCAD demonstrate the effectiveness of the proposed control methods.

关键词： Cyber-physical microgrid system(CPMS) microgrid automatic generation control(AGC) multiagent system(MAS) droop control global information discovery

Expert recommendation on collection,storage,annotation,and management of data related to medical artificial intelligence

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智慧医学(英文) 2023年第2期3卷 144-149页

作者： Yahan Yang Ruiyang li Yifan Xiang Duoru lin Anqi Yan Wenben Chen zhongwen li Weiyi Lai Xiaohang Wu Cheng Wan Wei Bai Xiucheng Huang Qiang li Wenrui Deng Xiyang liu Yucong lin Pisong Yan Haotian lin Chinese Association of Artificial Intelligence Medical Artificial Intelligence Branch of Guangdong Medical Association Zhongshan Ophthalmic Center Sun Yat-sen UniversityState Key Laboratory of OphthalmologyGuangzhouGuangdong 510623China Zhongshan School of Medicine Sun Yat-sen UniversityGuangzhouGuangdong 510080China Nanjing University of Aeronautics and Astronautics NanjingJiangsu 210016China Institute of Software Engineering School of Computer Science and TechnologyXidian UniversityXi’anShaanxi 710071China Cloud Intelligent Care Tech.Ltd. GuangzhouGuangdong 510115China Centre for Precision Medicine Sun Yat-sen UniversityGuangzhouGuangdong 510080China 不详

Medical artificial intelligence(AI)and big data technology have rapidly advanced in recent years,and they are now routinely used for image-based diagnosis.China has a massive amount of medical data.However,a uniform criteria for medical data quality have yet to be established.Therefore,this review aimed to develop a standardized and detailed set of quality criteria for medical data collection,storage,annotation,and management related to medical AI.This would greatly improve the process of medical data resource sharing and the use of AI in clinical medicine.

关键词： Artificial intelligence Big data Intelligent medicine Data collection Data storage Data annotation Data management

A Stochastic Programming Strategy in Microgrid Cyber Physical Energy System for Energy Optimal Operation

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IEEE/CAA Journal of Automatica Sinica 2015年第3期2卷 296-303页

作者： Hepeng li Chuanzhi Zang Peng Zeng Haibin Yu zhongwen li the Laboratory of Networked Control Systems Shenyang Institute of AutomationChinese Academy of Sciences

This paper focuses on the energy optimal operation problem of microgrids(MGs) under stochastic environment.The deterministic method of MGs operation is often uneconomical because it fails to consider the high randomness of unconventional energy resources.Therefore,it is necessary to develop a novel operation approach combining the uncertainty in the physical world with modeling strategy in the cyber system.This paper proposes an energy scheduling optimization strategy based on stochastic programming model by considering the uncertainty in MGs.The goal is to minimize the expected operation cost of MGs.The uncertainties are modeled based on autoregressive moving average(ARMA) model to expose the effects of physical world on cyber world.Through the comparison of the simulation results with deterministic method,it is shown that the effectiveness and robustness of proposed stochastic energy scheduling optimization strategy for MGs are valid.

关键词： Microgrids(MGs) cyber physical energy system(CPES) uncertainty stochastic programming energy optimal operation

新型电力系统中异质调频机组分布式协同AGC方法研究

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电网技术 2024年第6期48卷 2327-2335,I0023-I0025页

作者：李忠文柏宁宁程志平王义随权郑州大学电气与信息工程学院河南省郑州市450001

“双碳”目标的实施加速了新型电力系统发展。然而,新型电力系统的转动惯量和调节能力逐渐难以适应复杂多变的负荷变化。因此,开发更高效、更快速的调频资源参与自动发电控制(automatic generation control,AGC)已成为刻不容缓之事。但... 详细信息

“双碳”目标的实施加速了新型电力系统发展。然而,新型电力系统的转动惯量和调节能力逐渐难以适应复杂多变的负荷变化。因此,开发更高效、更快速的调频资源参与自动发电控制(automatic generation control,AGC)已成为刻不容缓之事。但是,不同调频机组之间的异质性显著,包括机组模型、容量和响应速度的差异,这对AGC提出了挑战。为了提升异质调频资源参与AGC的性能,该文提出了一种分布式协同AGC方法。首先,基于分布式固定时间一致性理论提出了一种分布式固定时间区域控制偏差(area control error,ACE)发掘算法。随后,各AGC机组根据获取的ACE信息设计独立的PI控制器参与频率调节。在ACE调节的最后阶段,根据各机组出力的标幺值,设计了分布式固定时间功率均分控制器,控制低速AGC机组承担更多的功率调整量,从而释放高速AGC机组的容量并为下一轮AGC服务做好准备。通过对包含5种不同调频单元的两区域电力系统进行仿真研究,验证了所提分布式协同AGC方法的性能。结果表明,所提方法可以有效地提高系统的调频性能,且能够在设计的时间内实现期望的有功功率分配。

关键词：负载频率控制新型电力系统分布式一致性固定时间自动发电控制电力电子化

Immunity-and-matrix-regulatory cells enhance cartilage regeneration for meniscus injuries: a phase I dose-escalation trial

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Signal Transduction and Targeted Therapy 2023年第12期8卷 5873-5886页

作者： liangjiang Huang Song Zhang Jun Wu Baojie Guo Tingting Gao Sayed Zulfiqar Ali Shah Bo Huang Yajie li Bo Zhu Jiaqi Fan liu Wang Yani Xiao Wenjing liu Yao Tian Zhengyu Fang Yingying Lv lingfeng Xie Sheng Yao Gaotan Ke Xiaolin Huang Ying Huang Yujuan li Yi Jia zhongwen li Guihai Feng Yan Huo Wei li Qi Zhou Jie Hao Baoyang Hu Hong Chen Department of Rehabilitation Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina National Stem Cell Resource Center State Key Laboratory of Stem Cell and Reproductive BiologyInstitute of ZoologyInstitute for Stem Cell and RegenerationChinese Academy of SciencesBeijingChina Beijing Institute for Stem Cell and Regenerative Medicine BeijingChina Department of Radiology Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina Stem Cell Research Center Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina Department of Orthopedics Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina University of Chinese Academy of Sciences BeijingChina Beijing Key Lab for Pre-clinical Safety Evaluation of Drugs National Center for Safety Evaluation of DrugsNational Institutes for Food and Drug ControlBeijingChina Beijing Zephyrm Biotechnologies Co. Ltd.BeijingChina

Immunity-and-matrix-regulatory cells(IMRCs)derived from human embryonic stem cells have unique abilities in modulating immunity and regulating the extracellular matrix,which could be mass-produced with stable biological properties.Despite resemblance to mesenchymal stem cells(MSCs)in terms of self-renew and tri-lineage differentiation,the ability of IMRCs to repair the meniscus and the underlying mechanism remains undetermined.Here,we showed that IMRCs demonstrated stronger immunomodulatory and pro-regenerative potential than umbilical cord MSCs when stimulated by synovial fluid from patients with meniscus injury.Following injection into the knees of rabbits with meniscal injury,IMRCs enhanced endogenous fibrocartilage regeneration.In the dose-escalating phase I clinical trial(NCT03839238)with eighteen patients recruited,we found that intra-articular IMRCs injection in patients was safe over 12 months post-grafting.Furthermore,the effective results of magnetic resonance imaging(MRI)of meniscus repair and knee functional scores suggested that 5×107 cells are optimal for meniscus injury treatment.In summary,we present the first report of a phase I clinical trial using IMRCs to treat meniscus injury.Our results demonstrated that intra-articular injection of IMRCs is a safe and effective therapy by providing a permissive niche for cartilage regeneration.

关键词： meniscus injuries cartilage

Changes in P2Y purinoreceptor-mediated intracellular calcium signal pathways results in inositol-1, 4, 5-triphosphate-sensitive calcium stores in rat small trigeminal ganglion neurons

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Neural Regeneration Research 2010年第12期5卷 906-910页

作者： Yuanyin Wang Andong liu Jie Lei Min Xie zhongwen li liecheng Wang Stomatological Hospital Anhui Medical University Hefei 230032 Anhui Province China Department of Physiiology School of Basic Medical Science Anhui Medical University Hefei 230032 Anhui Province China

BACKGROUND： Most of the currently available information on purinergic receptors （P2Rs） involved in pain transmission is based on results obtained in dorsal root ganglion or the spinal cord. However, the mechanism of P2Rs in trigeminal neuralgia remains unclear. OBJECTIVE： To investigate changes in the P2R-mediated calcium signaling pathway in nociceptive trigemJnal ganglion neurons. DESIGN, TIME AND SETTING： In vitro experiments were conducted at the Patch-Clamp Laboratory of Comprehensive Experiment Center of Anhui Medical University, China from September 2008 to June 2009. MATERIALS： Thapsigargin, caffeine, suramin, and adenosine 5＇-triphosphate were purchased from Sigma, USA. METHODS： Using Fura-2-based microfluorimetry, intracellular calcium concentration （[Ca^2＋]i） was measured in freshly isolated adult rat small trigeminal ganglion neurons before and after drug application. MAIN OUTCOME MEASURES： Fluorescent intensities were expressed as the ratio F340/F380 to observe [Ca^2＋]i changes. RESULTS： In normal extracellular solution and Ca^2＋-free solution, application of thapsigargin （1 μmol/L）, a sarcoplasmic reticulum Ca^2＋ pump adenosine 5＇-triphosphate inhibitor, as well as caffeine （20 mmol/L）, a ryanodine receptor agonist, triggered [Ca^2＋]i increase in small trigeminal ganglion neurons. A similar response was induced by application of adenosine 5＇-triphosphate （100 μmol/L）. In Ca^2＋-free conditions, adenosine 5＇-triphosphate-induced [Ca^2＋]i transients in small trigeminal ganglion neurons were inhibited in cells pre-treated with thapsigargin （P 〈 0.01）, but not by caffeine （P 〉 0.05）. In normal, extracellular solution, adenosine 5＇-triphosphate-induced [Ca^2＋]i transients in small trigeminal ganglion neurons were partly inhibited in cells pre-treated with thapsigargin （P 〈 0.05）. CONCLUSION： Inositol-1,4, 5-triphosphate （IP3）- and ryanodine-sensitive Ca^2＋ stores exist in rat nociceptive trigeminal ganglion neurons. Two pathways are involved in the purinoreceptor-mediated [Ca^2＋]i rise observed in nocicep

关键词： calcium stores cytoplasmic calcium trigeminal ganglion adenosine 5＇-triphosphate purinergic receptors neurotrophic factor trigeminal neuralgia neural regeneration

基于VSG下垂优化控制的新能源电力系统惯性提升

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郑州大学学报（工学版） 2024年第3期45卷 127-133页

作者：王明东杨岙迪李龙好李忠文郑州大学电气与信息工程学院河南郑州450001 许继电气股份有限公司河南许昌461000

针对传统VSG技术动态性能较差且重要参数J和D最优值较难确定的问题,提出了一种基于下垂控制与神经网络预测的VSG控制与参数优化策略,实现了VSG技术中关键参数J和D的动态调节。首先,所提策略将有功功率-频率下垂控制应用于VSG的控制算法... 详细信息

针对传统VSG技术动态性能较差且重要参数J和D最优值较难确定的问题,提出了一种基于下垂控制与神经网络预测的VSG控制与参数优化策略,实现了VSG技术中关键参数J和D的动态调节。首先,所提策略将有功功率-频率下垂控制应用于VSG的控制算法中;其次,通过模拟同步发电机转子运动方程和电压与无功控制特性,建立VSG的小信号分析模型,完成了关键参数转动惯量与阻尼系数的初值整定;最后,建立了人工神经网络进行分析学习和网络训练,调整权值以改变VSG转动惯量与阻尼系数,通过误差函数比较输出量与输入量之间的误差,多次学习训练后参数达到期望值。将神经网络优化算法与下垂控制策略结合,对VSG控制策略进行优化。分别采用传统VSG控制、恒定参数下垂控制和基于神经网络优化的自适应参数下垂控制对算例进行仿真,结果表明:所提基于神经网络优化的自适应参数下垂控制比传统VSG控制的频率最大变化量降低了26.7%,频率稳定时间降低了0.25 s,表明了所提策略的有效性。

关键词：新能源电力系统 VSG 下垂控制神经网络小信号分析模型