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Migratable Power System Transient Stability AssessmentMethod Based on Improved XGBoost

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Energy Engineering 2024年第7期121卷 1847-1863页

作者： Ying Qu jinhao Wang Xueting Cheng Jie Hao Weiru Wang Zhewen Niu Yuxiang Wu Electric Power Science Research Institute State Grid Shanxi Electric Power CompanyTaiyuan030000China Department of Electrical and Power Engineering Taiyuan University of TechnologyTaiyuan030024China

The data-driven transient stability assessment(TSA)of power systems can predict online real-time prediction by learning the temporal features before and after ***,the accuracy of the assessment is limited by the quality of the data and has weak *** on this,this paper proposes a method for TSA of power systems based on an improved extreme gradient boosting(XGBoost)***,the gradient detection method is employed to remove noise interference while maintaining the original time series *** this basis,a focal loss function is introduced to guide the training of theXGBoostmodel,enhancing the deep exploration of minority class samples to improve the accuracy of the model ***,to improve the generalization ability of the evaluation model,a transfer learning method based on model parameters and sample augmentation is *** simulation analysis on the IEEE 39-bus system demonstrates that the proposed method,compared to the traditional machine learning-based transient stability assessment approach,achieves an average improvement of 2.16%in evaluation ***,under scenarios involving changes in topology structure and operating conditions,the accuracy is enhanced by 3.65%and 3.11%,***,the model updating efficiency is enhanced by 14–15 times,indicating the model’s transferable and adaptive capabilities across multiple scenarios.

关键词： Transient stability assessment data-driven segmented focusing approximation portability

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PEMFC阴极过氧比控制方法研究

西北工业大学学报 2020年第5期38卷 987-993页

作者：夏磊赵冬冬李飞王西坡孟锦豪西北工业大学自动化学院陕西西安710072 四川大学四川成都610065

质子交换膜燃料电池(PEMFC)由于其高功率密度和低工作温度,被认为是具有应用前景的一种新能源技术。过氧比(OER)是影响燃料电池系统性能的重要因素之一。过氧比控制的核心是通过控制阴极的空气流量输入,防止发生“氧饥饿”现象,在维持... 详细信息

质子交换膜燃料电池(PEMFC)由于其高功率密度和低工作温度,被认为是具有应用前景的一种新能源技术。过氧比(OER)是影响燃料电池系统性能的重要因素之一。过氧比控制的核心是通过控制阴极的空气流量输入,防止发生“氧饥饿”现象,在维持系统正常运行的前提下对系统净功率进行优化,提升系统的性能。首先在MATLAB中建立了基于空气供应系统的PEMFC六阶动态模型,获得过氧比关于负载电流的函数关系。在PID控制、模糊控制、super⁃twisting二阶滑模控制的基础上,提出了一种改进的模糊-滑模控制策略。仿真结果表明,该方法具有良好的鲁棒性和快速调节的性能。

关键词： PEMFC空气供气系统过氧比模糊-滑模控制系统仿真

基于最大相关熵扩展卡尔曼滤波算法的锂离子电池荷电状态估计

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电工技术学报 2021年第24期36卷 5165-5175页

作者：巫春玲胡雯博孟锦豪刘智轩程琰清长安大学电子与控制工程学院西安710061 四川大学电气工程学院成都610065

针对在非高斯噪声干扰下,传统扩展卡尔曼滤波(EKF)算法估计锂离子电池荷电状态(SOC)时精度低的问题,该文提出一种基于最大相关熵的扩展卡尔曼滤波新算法(MCC-EKF),用于估计锂离子电池的荷电状态。首先对锂离子电池进行Thevenin等效电路... 详细信息

针对在非高斯噪声干扰下,传统扩展卡尔曼滤波(EKF)算法估计锂离子电池荷电状态(SOC)时精度低的问题,该文提出一种基于最大相关熵的扩展卡尔曼滤波新算法(MCC-EKF),用于估计锂离子电池的荷电状态。首先对锂离子电池进行Thevenin等效电路建模,并对该模型中的参数进行辨识;然后在不同噪声类型干扰下,分别运用所提出新算法MCC-EKF和EKF算法对电池进行SOC估计。实验结果表明,与EKF算法相比,新算法在高斯噪声干扰下,运行时间增加0.282s,估计精度提高19%;在非高斯噪声干扰下,运行时间增加0.418s,估计精度提高51%;可见新算法的估计精度高于EKF算法,尤其是在非高斯噪声干扰下,新算法的估计精度有显著性提高。另外,新算法在给定错误初始SOC值的情况下,在电池开始工作后10s内就能够收敛到真实值,说明新算法具有较好的鲁棒性。故新算法在运行时间增加很小的情况下,估计精度高且鲁棒性好,是一种非常有效的SOC估计方法。

关键词：锂离子电池参数辨识非高斯噪声荷电状态

基于改进LightGBM的电动汽车电池剩余使用寿命在线预测

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电工技术学报 2022年第17期37卷 4517-4527页

作者：肖迁穆云飞焦志鹏孟锦豪贾宏杰智能电网教育部重点实验室(天津大学) 天津300072 省部共建电工装备可靠性与智能化国家重点实验室(河北工业大学) 天津300130 四川大学电气工程学院成都610065

为实现电池剩余使用寿命(RUL)在线预测和降低数据离群值对预测精度影响,提出基于改进轻量型梯度提升机(LightGBM)的RUL在线预测方法。首先,为实现RUL在线预测,通过等压降时间与容量衰减的关系,选取等压降时间为健康因子;然后,为降低数... 详细信息

为实现电池剩余使用寿命(RUL)在线预测和降低数据离群值对预测精度影响,提出基于改进轻量型梯度提升机(LightGBM)的RUL在线预测方法。首先,为实现RUL在线预测,通过等压降时间与容量衰减的关系,选取等压降时间为健康因子;然后,为降低数据离群值对预测精度的影响,构建基于LightGBM的预测模型,采用Bagging的学习方式,忽略离群值权重;接着,为进一步降低离群值影响,基于一种兼具自适应性和鲁棒性的损失函数(ARLF)对LightGBM进行改进,通过超参数α限制损失函数一阶导数幅值的饱和值,在残差增长时,限制离群值对梯度的影响;最后,通过行驶工况下电池全生命周期容量测试实验数据,对比基于不同损失函数的RUL在线预测效果,验证所构建健康因子和所提预测方法的有效性。

关键词：锂离子电池剩余使用寿命在线预测离群值改进轻量型梯度提升机

Bidirectional energy-controlled piezoelectric shunt damping technology and its vibration attenuation performance

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International Journal of Mechanical System Dynamics 2024年第1期4卷 63-76页

作者： Yipeng Wu Quan Yuan Kaibin Ren Xin Shen Hui Shen Adrien Badel Hongli Ji jinhao Qiu State Key Laboratory of Mechanics and Control for Aerospace Structures Nanjing University of Aeronautics and AstronauticsNanjingChina College of Mechanical and Electrical Engineering Qingdao UniversityQingdaoChina SYMME Laboratory Universite Savoie Mont BlancAnnecy le VieuxFrance

Piezoelectric material-based semi-active vibration control systems may effectively suppress vibration amplitude without any external power supply,or even harvest electrical *** bidirectional electrical energy control phenomenon is theoretically introduced and validated in this paper.A flyback transformer-based switching piezoelectric shunt circuit that can extract energy from or inject energy into piezoelectric elements is *** analytical expressions of the controlled energy and the corresponding vibration attenuation are therefore derived for a classical electromechanical cantilever *** predictions validated by the experimental results show that the structure vibration attenuation can be tuned from−5 to−25 dB under the given electrical quality factor of the circuit and figure of merit of the electromechanical structure,and the consumed power is in the range of−13 to 25 mW,which is a good theoretical basis for the development of self-sensing,self-adapting,and self-powered piezoelectric vibration control systems.

关键词： vibration control piezoelectric shunt damping electromechanical energy

Vibration Reduction by a Partitioned Dynamic Vibration Absorber with Acoustic Black Hole Features

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Chinese Journal of Mechanical Engineering 2024年第4期 133-147页

作者： Xiaoning Zhao Chaoyan Wang Hongli Ji jinhao Qiu Li Cheng State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and Astronautics Nanjing Institute of Information Technology Department of mechanical Engineering Hong Kong Polytechnic University

Vibration quality is a vital indicator for assessing the progress of modern equipment. The dynamic vibration absorber(DVA) based on the acoustic black hole(ABH) feature is a new passive control method that manipulates waves. It offers efficient energy focalization and broad-spectrum vibration suppression, making it highly promising for applications in large equipment such as aircraft, trains, and ships. Despite previous advancements in ABH-DVA development,certain challenges remain, particularly in ensuring effective coupling with host structures during control. To address these issues, this study proposes a partitioned ABH-featured dynamic vibration absorber(PABH-DVA) with partitions in the radial direction of the disc. By employing a plate as the host structure, simulations and experiments were conducted, demonstrating that the PABH-DVA outperforms the original symmetric ABH-DVA in terms of damping performance. The study also calculated and compared the coupling coefficients of the two ABH-DVAs to uncover the mechanism behind the enhanced damping. Simulation results revealed that the PABH-DVA exhibits more coupled modes, occasionally with lower coupling coefficients than the symmetric ABH-DVA. The influence of frequency ratio and modal mass was further analyzed to explain the reasons behind the PABH-DVA's superior damping ***, the study discussed the impact of the number of slits and their orientation. This research further explains the coupling mechanism between the ABH-DVA and the controlled structure, and provides new ideas for the further application of ABH in engineering.

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基于驱动电流动态调节的低过冲低损耗SiC MOSFET有源门极驱动

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中国电机工程学报 2020年第18期40卷 5730-5741页

作者：刘平李海鹏苗轶如陈常乐陈梓健孟锦豪湖南大学电气与信息工程学院湖南省长沙市410006 四川大学电气工程学院四川省成都市610065

与硅基功率器件相比,碳化硅(silicon carbide,SiC)MOSFET具有开关速度更快、导通损耗更低等优点,将越来越广泛的应用于高效高功率密度场合。但是,其开关特性对寄生参数非常敏感,在高速开关过程中极易产生瞬态电压电流尖峰和高频开关振荡... 详细信息

与硅基功率器件相比,碳化硅(silicon carbide,SiC)MOSFET具有开关速度更快、导通损耗更低等优点,将越来越广泛的应用于高效高功率密度场合。但是,其开关特性对寄生参数非常敏感,在高速开关过程中极易产生瞬态电压电流尖峰和高频开关振荡,严重威胁Si C基变换器的可靠运行。针对这一问题,文中对SiC MOSFET的开关暂态过程进行深入分析,揭示门极驱动电流对开关过程电压电流过冲、振荡与开关损耗的影响机理。在此基础上,提出一种驱动电流分段动态调节的SiC MOSFET有源门极驱动电路,即根据开关过程不同阶段的状态反馈动态调整器件门极驱动电流。实验结果表明,所提出的方法能够在维持低开关损耗的同时,实现了对SiC MOSFET开关过程中电压电流过冲和高频振荡的有效抑制,提升SiC基电力电子装置的动态性能与运行可靠性。

关键词： SiC MOSFET 有源门极驱动电流动态调节过冲振荡开关损耗

Sensitive humidity sensor based on moisture-driven energy generation

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Nano Research 2024年第6期17卷 5578-5586页

作者： Qingchao Ni Qing Lou Chenglong Shen Guangsong Zheng Runwei Song Jingnan Hao Jialu Liu Jinyang Zhu jinhao Zang Lin Dong Chong-Xin Shan Henan Key Laboratory of Diamond Optoelectronic Materials and Devices Key Laboratory of Materials PhysicsMinistry of Educationand School of Physics and MicroelectronicsZhengzhou UniversityZhengzhou 450052China State Centre for International Cooperation on Designer Low-Carbon&Environmental Materials and School of Materials Science and EngineeringZhengzhou UniversityZhengzhou 450001China

The emergence of novel self-powered humidity sensors has attracted considerable attention in the fields of smart electronic devices and personal ***,self-powered humidity sensors have been fabricated using a moisture-driven energy generation(MEG)device based on asymmetric tubular graphitic carbon nitride(g-CN)films prepared on anodized aluminum(AAO)*** a relative humidity(RH)of 96%,the MEG device can provide an open-circuit voltage of 0.47 V and a short-circuit current of 3.51μA,with a maximum output power of 0.08μ*** inherent self-powered ability and humidity response via current variation,an extraordinary response of 1.78×106%(41%-96%RH)can be gained from the MEG *** possible power generation mechanism is that g-CN/AAO heterostructure can form ion gradient and diffusion under the action of moisture to convert chemical potential into electrical potential,evoking a connaturally sensitive response to ***-powered respiration monitoring device based on the sensor is designed to monitor human movement(sitting,warming up,and running)and sleep status(normal,snoring,and apnea),maintaining excellent stability during cumulative 12-h respiration *** self-powered humidity sensing technology has promising potential for extensive integration into smart electronic and round-the-clock health monitoring devices.

关键词： graphitic carbon nitride moisture-driven energy generation humidity sensor respiration monitoring

Night warming increases wheat yield by improving pre-anthesis plant growth and post-anthesis grain starch biosynthesis

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Journal of Integrative Agriculture 2024年第2期23卷 536-550页

作者： Yonghui Fan Boya Qin jinhao Yang Liangliang Ma Guoji Cui Wei He Yu Tang Wenjing Zhang Shangyu Ma Chuanxi Ma Zhenglai Huang College of Agronomy Anhui Agricultural University/Key Laboratory of Wheat Biology and Genetic Improvement in South Yellow&Huai River ValleyMinistry of Agriculture and Rural AffairsHefei 230036China Xianyang Central Station for Agricultural Technology Extension Xianyang 712000China

Global climate change is characterized by asymmetric warming,i.e.,greater temperature increases in winter,spring,and nighttime than in summer,autumn,and *** experiments were conducted using four wheat cultivars,namely‘Yangmai 18’(YM18),‘Sumai 188’(SM188),‘Yannong 19’(YN19),and‘Annong 0711’(AN0711),in the two growing seasons of 2019-2020 and 2020-2021,with passive night warming during different periods in the early growth *** treatments were night warming during the tillering-jointing(NW_(T-J)),jointing-booting(NWJ-B),and booting-anthesis(NWB-A)stages,with ambient temperature(NN)as the *** effects of night warming during different stages on wheat yield formation were investigated by determining the characteristics of dry matter accumulation and translocation,as well as sucrose and starch accumulation in wheat *** wheat yields of all four cultivars were significantly higher in NW_(T-J)than in NN in the 2-year *** yield increases of semi-winter cultivars YN19 and AN0711 were greater than those of spring cultivars YM18 and *** NW_(T-J)increased wheat yield mainly by increasing the 1,000-grain weight and the number of fertile spikelets,and it increased dry matter accumulation in various organs of wheat at the anthesis and maturity stages by increasing the growth rate at the vegetative growth *** flag leaf and spike showed the largest increases in dry matter ***_(T-J)also increased the grain sucrose and starch contents in the early and middle grain-filling stages,promoting yield ***,night warming between the tillering and jointing stages increased the pre-anthesis growth rate,and thus,wheat dry matter production,which contributed to an increase in wheat yield.

关键词： wheat asymmetric warming dry matter accumulation and translocation starch yield