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A Novel Charging Strategy to Reduce Voltage Variation for Reconfigurable Energy Storage System of Modern Tram

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A Novel Charging Strategy to Reduce Voltage Variation for Re...

第37届中国控制会议

作者： Baolin Zhu hongtao liao Rui Wang Yun Jiao Zhiwu Huang Jun Peng School of Information Science and Engineering Central South University Hunan Engineering Laboratory of Rail Vehicles Braking Technology CRRC Zhu Zhou Locomotive Co. Ltd.

Due to the voltage limitation, large number of ultracapacitor cells need to be connected in parallel and series to provide a specific voltage level for trams. However, a large scale of series-connected ultracapacitors increase the voltage variation of the DC bus, which affects the size and efficiency of the subsequent power converter stage and undermines the energy utilization of the ultracapacitor. Moreover, ultracapacitors in series-connection inevitably suffer from voltage imbalance, which limits the capacity of energy storage system by the weakest cell. To alleviate the above problems, ultracapacitor parallel-series reconfiguration is employed to reduce the voltage variation in this paper. Particularly, a synchronous equilibrium strategy based on consensus tracking control is designed for voltage balance among series-connected ultracapacitors. First, we mathematically model the ultracapacitor-based energy storage system using the state-space averaging method. Second, the law of reconfiguration and synchronous equilibrium strategy is analyzed and designed. Finally, both simulation and experiment results verify that the proposed charging strategy effectively suppresses the voltage variation of the DC bus and evidently reduces balance time during charging.

关键词： Ultracapacitor Reconfigurable topology The voltage variation Voltage imbalance

An Optimal Current-Sharing Control for Parallel Charging System With Supercapacitors using Pseudospectral Method

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An Optimal Current-Sharing Control for Parallel Charging Sys...

第37届中国控制会议

作者： Rui Zhang Jun Peng Bin Chen Shou Li hongtao liao Kuo-Chi Lin School of Information and Engineering Central South University Hunan Engineering Laboratory of Rail Vehicles Braking Technology School of Electrical and Information Engineering Changsha University of Science and Technology CRRC ZhuZhou Locomotive Co. Ltd. Department of Mechanical and Aerospace Engineering University of Central Florida

The current-sharing is a critical issue for parallel charging system with supercapacitors,which is a high-order nonlinear system with control inputs *** the paper,a uniform pseudospectral real-time closed-loop optimal control framework is proposed for constrained current-sharing control to minimize the charging time based on Radau Pseudospectral Method（RPM）.In the framework,the current-sharing requirements are formulated as trajectory constraints utilizing the leader-follower structure with bounded *** receding horizon control principle and pseudospetral observer are developed to construct a constrained closed-loop optimal control,in which RPM is leveraged to obtain real-time optimal *** results verify the effectiveness of the proposed approach.

关键词： Current-sharing Optimal control RPM

A Practical and Efficient Nonlinear Observer for Supercapacitor Energy Identification

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A Practical and Efficient Nonlinear Observer for Supercapaci...

第37届中国控制会议

作者： hongtao liao Jun Peng Yanhui Zhou Yingze Yang Zhiwu Huang Kuo-Chi Lin School of Information Science and Engineering Central South University Hunan Engineering Laboratory of Rail Vehicles Braking Technology CRRC Zhu Zhou Locomotive Co. Ltd. Department of Mechanical and Aerospace Engineering University of Central Florida

In this paper, a novel nonlinear observer is proposed to accurately identify supercapacitor（SC） energy. With the consideration of dynamic modeling uncertainty, a nonlinear state space model is established based on the SC three branch equivalent circuit model. A piecewise nonlinear feedback function is designed by employing sign function, whose gain is adaptively adjusted. By using the nonlinear function apply for correcting SC model uncertainty, the discrete nonlinear observer is designed. With the observer, the corrected internal capacitor voltages is derived and thus the SC energy is identified. With an elaborately designed experimental scheme, a test platform is built. The derived experimental results show that the energy observation error is 0.4% in charging stage and 1% in discharging stage, which verified the practicability and high accuracy of the proposed energy identification method.

关键词： Supercapacitor Energy Nonlinear observer Identification

Radiofrequency catheter ablation of idiopathic ventricular arrhythmias originating from coronary vein system

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Radiofrequency catheter ablation of idiopathic ventricular a...

中华医学会第十五次全国心血管病学大会

作者： Teng Li Xianzhang Zhan Yumei Xue Xianhong Fang hongtao liao Wei Wei Shulin Wu Guangdong General Hospital Guangdong Cardiovascular Institute

Objective The purpose of this study was to determine the safety and efficacy of radiofrequency catheter ablation(RFCA) of frequent premature ventricular contractions(PVCs) or ventricular tachycardia(VT) originating from Coronary vein system(CVS). Methods 11 patients (7 men;age, 47.08±15.16 years) were found to have an CVS origin who were

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阿法骨化醇、血液灌流及透析治疗慢性肾脏病

中国继续医学教育 2020年第13期12卷 128-131页

作者：廖洪涛湖北省洪湖市中医医院肾内科湖北荆州433200

目的探究分析阿法骨化醇联合血液灌流与血液透析对慢性肾脏病-矿物质和骨异常(KD-MBD)患者钙磷代谢的影响。方法将2017年1月-2019年1月的72例慢性肾脏病-矿物质和骨异常的患者纳入研究范围,并应用随机数字表的方式对其平均分组,分别应... 详细信息

目的探究分析阿法骨化醇联合血液灌流与血液透析对慢性肾脏病-矿物质和骨异常(KD-MBD)患者钙磷代谢的影响。方法将2017年1月-2019年1月的72例慢性肾脏病-矿物质和骨异常的患者纳入研究范围,并应用随机数字表的方式对其平均分组,分别应用阿法骨化醇联合血液灌流与血液透析方式(试验组)进行治疗干预及血液灌流与血液透析方式(对照组)进行干预,对比治疗效果。结果经研究,试验组的血磷水平、血钙水平和甲状旁激素水平显著优于对照组,且试验组患者的血肌酐、血尿素氮和尿酸水平均显著优于对照组,差异具有统计学意义,P<0.05。结论在血液灌流与血液透析的基础上,联合应用阿法骨化醇,有利于改善患者的肾脏功能,优化钙磷代谢情况。

关键词：阿法骨化醇血液灌流血液透析慢性肾脏病矿物质和骨异常钙磷代谢

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原子层沉积法制备氧化锌纳米管

功能材料 2018年第10期49卷 12-15页

作者：廖荣刘慧君柯嘉聪李涌春廖鸿韬罗志勇华南理工大学电子与信息学院广州510640

采用原子层沉积法成功制备出了大小均匀、形貌规则、晶体质量较好的ZnO纳米管,利用扫描电镜(SEM)、X射线衍射仪(XRD)、X射线光电子能谱(XPS)等对样品表面形貌和物相进行分析,得到的ZnO纳米颗粒为六角纤锌矿结构,纳米管外径2μm,壁厚150n... 详细信息

采用原子层沉积法成功制备出了大小均匀、形貌规则、晶体质量较好的ZnO纳米管,利用扫描电镜(SEM)、X射线衍射仪(XRD)、X射线光电子能谱(XPS)等对样品表面形貌和物相进行分析,得到的ZnO纳米颗粒为六角纤锌矿结构,纳米管外径2μm,壁厚150nm。还可选用其它孔径的聚碳酸酯薄膜以及不同的原子层沉积循环数,控制管壁的厚度,以得到不同直径的ZnO纳米管。该方法工艺简单,操作简便,无任何中间产物,可实现工业化生产。

关键词：氧化锌纳米管原子层沉积法聚碳酸酯薄膜生长机理

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人工智能、政府政策以及企业劳动力需求

上海商学院学报 2023年第5期24卷 43-63页

作者：廖宏涛曾庆芬西南民族大学经济学院成都610041

人工智能导致的就业不确定性引发了社会的广泛担忧,既有研究结论尚未达成一致。我国政府不断出台促进人工智能发展的政策是否会放大这种不确定性?本文从理论上分析人工智能的替代效应和创造效应,并讨论政府人工智能政策介入的影响,利用2... 详细信息

人工智能导致的就业不确定性引发了社会的广泛担忧,既有研究结论尚未达成一致。我国政府不断出台促进人工智能发展的政策是否会放大这种不确定性?本文从理论上分析人工智能的替代效应和创造效应,并讨论政府人工智能政策介入的影响,利用2009—2020年A股上市公司面板数据及文本分析法探究了我国政府政策对人工智能发展以及劳动力就业市场的影响。研究发现,人工智能整体上促进了企业劳动力需求,并且在人工智能代表性政策《中国制造2025》实施后,不仅企业人工智能水平得到提升,而且企业劳动力需求也显著提高。异质性分析结果显示,在代表性政策影响下,企业劳动力需求出现极化现象。其中,低技术企业劳动力需求降低,而高技术企业劳动力需求增加,并且在高技术企业中,资本密集型企业创造的岗位数量多于技术密集型企业。同时,政府政策弥合了所有制和区域因素带来的企业用工差异,促进了劳动力就业市场的均衡发展。综上,政府在发展人工智能的同时,应关注低技能者的就业和劳动力市场的极化现象,推动人机结合,并提供差异化发展策略。

关键词：人工智能政府政策《中国制造2025》企业劳动力需求