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Research on Power Flow Algorithm for Power System Including Wind Farm

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Research on Power Flow Algorithm for Power System Including ...

Flexible assistance strategy of lower limb rehabilitation exoskeleton based on admittance model

第11届国际电机与系统学术会议

作者： yanni Liu~1 Wei Wang~1 Lijie Xu~1 Pinghao Ni~1 lin Wang~2.1 {2. of electrical Engineering beijing Jiaotong university beijing 100044 china 2.Jilin Power Supply Company Jilin 132.01 china

＜正＞On the base of studying on existing wind farm models in power flow calculation,two improved power flow algorithms for power system including wind farm which may be composed of squirrel cage induction generators（SCIG） or doubly-fed induction generators（DFIG） are presented in this *** reactive power of wind farm is rectified synchronously in every power flow iterative process,the improved algorithms avoid additional calculation hold low-computational costs and respectively reflect the two kinds of wind farms characteristics *** algorithms are used in two example systems to calculate power flow and the results show that they are veracious and time saving.

关键词： Double-fed induction generator Power flow calculation Squirrel cage induction generator Steady-state model Wind farm

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science china(Technological sciences) 2024年第3期67卷 823-834页

作者： KOU JianGe WANG YiXuan CHEN ZhenLei SHI yan GUO Qing XU Meng school of automation {2. and electrical Engineering Beihang UniversityBeijing 100191China school of aeronautics and {2. University of Electronic Science and Technology of ChinaChengdu 611731China Department of Musculoskeletal Tumor Senior Department of Orthopedicsthe Fourth Medical Centerof PLA GeneralHospitalBeijing 100853China

Exercise training based on exoskeleton is an effective rehabilitation method for stroke patients. However, some rehabilitation exoskeletons still have poor wearable performance and obvious human-robot impedance during training, which easily cause secondary injuries to the patients. In this study, a variable admittance control strategy is proposed to improve the operator's wearable comfort, which can adapt to different operators by regulating admittance parameters. The admittance controller has two feedback loops: the position inner-loop and the admittance outer-loop. Meanwhile, the exoskeleton Lagrange model is constructed with unknown friction disturbance. By using Lyapunov technique and backstepping with state observer, the joint position error of exoskeleton is convergence into a zero neighborhood. The effectiveness of the proposed admittance controller is verified by both simulation and experiment. The tracking error of hip and knee joint is less than 4 degrees while the human-robot interaction torque is constrained in a tolerable range of the operator.

关键词： human-robot interaction exoskeleton backstepping admittance control

Non-synchronous vibration of rotor blade in a six-stage transonic compressor

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Chinese Journal of aeronautics 2024年第8期37卷 36-48页

作者： Ronghui CHENG Zhuo WANG Huawei YU lin DU Yi ZHANG Xiaofeng SUN Aeroengine Research Institute Beihang UniversityBeijing 102206China school of Energy and Power Engineering Beihang UniversityBeijing 102206China

This paper presents an experimental study on the Non-Synchronous Vibration(NSV)in a six-stage transonic *** first part of the paper describes the NSV phenomenon of Rotor 1,which occurs when both Stator 1(S1)and Stator 2.S2.or S1 only are *** measurements and analysis are carried out for the former case through the unsteady wall pressure and the Blade Strain(BS).The spinning mode theory used in the rotor/stator interaction noise is employed to explain the relation between the circumferential wave number of the aerodynamic disturbance and the Nodal Diameter(ND)of the blade *** variations of the vibration amplitudes of different blades and the Inter-Blade Phase Angles(IBPAs)at different moments suggest that the evolution of NSV is a highly nonuniform phenomenon along the circumferential *** addition,the difference between the wall-pressure spectra generated by the NSV and the classic flutter has been *** the second part,the variations of aerodynamic loading due to the adjustment of the staggers of the Inlet Guide Vane(IGV),S1 and S2.have been *** is found that closing S1 only can result in a great fluctuation to the performance of the front stages,which might be detrimental to the flow organization and increase the risk of *** contrast,the effect of closing S2.only on the performance of the first two stages appears to be slighter relatively.

关键词： Transonic compressor Non-synchronous vibration Modal analysis Aerodynamic loading Nodal diameter

Quest for chirality in 107Ag

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Quest for chirality in 107Ag

Flight Simulator Table Servo Control Based on ADRC Strategy

第十三届全国核结构研讨会暨第九次全国“核结构与量子力学”专题讨论会

作者： HE Chuang-Ye~1 ZHANG Biao~(1,2. ZHU Li-Hua~(3,2. WU Xiao-Guang~1 SUN Hui-Bin~2.ZHENG Yun~1 WANG Lie-lin~(1,4) YU Bei-Bei~1 YAO Shun-He~1 LI Guang-sheng~1 XU Chuan~5 WANG Jian-Guo~6 GU Long~6 ZHANG Ming~6 1({2. Institute of Atomic Energy,beijing 102.13,{2.) 2.school of science,shenzhen university,shenzhen 518060,{2.) 3(school of physics and nuclear energy engineering,beijing university of aeronautics and astronautics,beijing 100191,{2.) 4(Department of Physics,Jilin university,Changchun 13002.,{2.) 5(school of Physics and MOE key laboratory of Heavy Ion Physics,Peking university,beijing 100087,{2.) 6(Department of Physics,Tsinghua university,beijing 100084,{2.)

High-Spin states in nuclei at A～100 mass region have been extensively studied in the recent years. There exists plenty of interesting phenomena in their structure,such as shape co-existence,band termination, magnetic rotations,chiral rotations and so *** them,the chirality attracted much attention both by theoretician and *** the previous study,doublet bands structure was found in *** present work,its neighbouring isotope Ag is selected to quest for the chiral bands.

关键词： high spin states level scheme chirality

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Flight Simulator Table Servo Control Based on ADRC Strategy

MADRL-based UAV swarm non-cooperative game under incomplete information

第二十九届中国控制会议

作者： LONG Man-lin 1,2.FUYong-ling 1,CHEN Shuang-Qiao 2.GUO Dong 1,3 1.{2. of automation science and electrical Engineering,Beihang university,beijing 100191,P.R.china2.College of Naval Architecture and Power,Naval university of Engineering,Wuhan 430033,P.R.china 3.Liaoning university of Technology,Jinzhou,Liaoning Province 12.000,P.R.china

For servo control of flight simulator table by electric-motor-drive,it would be hard to achieve high precise track by conventional algorithms or compensating means through accurate modeling due to several nonlinear or random factors,which are periodic ripple torque of motor,load fluctuation,errors of feedback sensors,friction,etc.,hence ADRC（Active-Disturbance-Rejection-Controller）is adopted to estimate and compensate above-mentioned factors on-line aiming at a better servo precision for the ***,ESO（Extended State Observer）of ADRC was designed by analyzing characteristics of flight simulator table inner-axis,thus the comprehensive disturbance instead of above-mentioned factors was observed and compensated simultaneously by ESO;secondly,Simulation study was done by establishing system model with extreme disturbance condition,and the parameters for ADRC were tuned through comparison of different simulation results;lastly,real experiment with well tuned controller was carried out to verify the validity of the algorithm on flight simulator table *** results from tracking a sine wave with amplitude of 2.show that the tracking error is great at the very moment of motor jump-starting and then is less than 0.0017°for the rest of the time,thus a high dynamic tracking performance is ***,simulation and experiment reveal that robustness of ADRC is strong and to tune its parameters on nominal model is feasible for actual control plant.

关键词： Flight Simulator Table ADRC Servo Control Disturbance Compensation

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Chinese Journal of aeronautics 2024年第6期37卷 293-306页

作者： Ershen WANG Fan LIU Chen HONG Jing GUO lin ZHAO Jian XUE Ning HE school of Electronic and Information Engineering Shenyang Aerospace UniversityShenyang 110136China College of Robotics Beijing Union UniversityBeijing 100101China school of Engineering science University of Chinese Academy of SciencesBeijing 100049China College of Smart City Beijing Union UniversityBeijing 100101China

Unmanned Aerial Vehicles(UAVs)play increasing important role in modern *** this paper,considering the incomplete observation information of individual UAV in complex combat environment,we put forward an UAV swarm non-cooperative game model based on Multi-Agent Deep Reinforcement Learning(MADRL),where the state space and action space are constructed to adapt the real features of UAV swarm air-to-air *** multi-agent particle environment is employed to generate an UAV combat scene with continuous observation *** recently popular MADRL methods are compared extensively in the UAV swarm noncooperative game model,the results indicate that the performance of Multi-Agent Soft Actor-Critic(MASAC)is better than that of other MADRL methods by a large *** swarm employing MASAC can learn more effective policies,and obtain much higher hit rate and win *** under different swarm sizes and UAV physical parameters are also performed,which implies that MASAC owns a well generalization ***,the practicability and convergence of MASAC are addressed by investigating the loss value of Q-value networks with respect to individual UAV,the results demonstrate that MASAC is of good practicability and the Nash equilibrium of the UAV swarm non-cooperative game under incomplete information can be reached.

关键词： UAV swarm Reinforcement learning Deep learning Multi-agent Non-cooperative game Nash equilibrium

结合门控循环单元的轴承故障声发射信息表征机制与定位

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振动工程学报 2024年第8期37卷 1442-1450页

作者：沈田刘宗阳李豪林京柳小勤汤林江北京航空航天大学可靠性与系统工程学院北京100191 昆明理工大学机电工程学院云南昆明650550

大型重载轴承工况特殊,在低速条件下,冲击持续时间拉长,系统响应幅度降低,故障信息更容易被噪声所掩盖。声发射技术具有对微弱损伤敏感的特性,被广泛应用于结构健康监测和设备状态检测。利用声发射技术中的空间定位方法,能够对大型低速... 详细信息

大型重载轴承工况特殊,在低速条件下,冲击持续时间拉长,系统响应幅度降低,故障信息更容易被噪声所掩盖。声发射技术具有对微弱损伤敏感的特性,被广泛应用于结构健康监测和设备状态检测。利用声发射技术中的空间定位方法,能够对大型低速重载轴承进行故障定位,效果依赖于信号准确到达时间。门控循环单元(GRU)网络能够考虑序列数据的内部相关性,提取时序特征,在信号处理中具有一定优势。赤池信息准则(AIC)利用统计学特征,能识别两个不同随机过程。本文提出一种基于GRU和AIC的声发射信号到达时间拾取方法,利用断铅与试验数据,与传统AIC、阈值判别、长/短时窗均值比等方法进行比较与分析,证明所提出方法能准确拾取声发射信号到达时间,在大型低速重载轴承故障定位方面具有较大应用潜力。

关键词：故障诊断轴承声发射初至拾取赤池信息准则门控循环单元

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Effects of air damping on quality factors of different probes in tapping mode atomic force microscopy

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Chinese Physics B 2024年第9期33卷 506-519页

作者： Yu Zeng Guo-lin Liu Jin-Hao Liu Zheng Wei school of Mechanical and electrical Engineering Beijing University of Chemical TechnologyBeijing 100029China

The AFM probe in tapping mode is a continuous process of energy dissipation,from moving away from to intermittent contact with the sample *** present,studies regarding the energy dissipation mechanism of this continuous process have only been reported sporadically,and there are no systematic explanations or experimental verifications of the energy dissipation mechanism in each stage of the continuous *** quality factors can be used to characterize the energy dissipation in TM-AFM *** this study,the vibration model of the microcantilever beam was established,coupling the vibration and damping effects of the microcantilever *** quality factor of the vibrating microcantilever beam under damping was derived,and the air viscous damping when the probe is away from the sample and the air squeeze film damping when the probe is close to the sample were *** addition,the mechanism of the damping effects of different shapes of probes at different tip–sample distances was *** accuracy of the theoretical simplified model was verified using both experimental and simulation methods.A clearer understanding of the kinetic characteristics and damping mechanism of the TM-AFM was achieved by examining the air damping dissipation mechanism of AFM probes in the tapping mode,which was very important for improving both the quality factor and the imaging quality of the TM-AFM *** study’s research findings also provided theoretical references and experimental methods for the future study of the energy dissipation mechanism of micro-nano-electromechanical systems.

关键词： TM-AFM quality factors air viscous damping air squeeze film damping

Dynamic analysis of beta oscillations in Parkinsonian neural networks with the pedunculopontine nucleus under optogenetic control

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Acta Mechanica Sinica 2024年第6期40卷 125-140页

作者： Yuzhi Zhao Honghui Zhang Ying Yu lin Du Zichen Deng school of Mathematics and Statistics Northwestern Polytechnical UniversityXi’an710072China school of Aeronautic science and Engineering Beihang UniversityBeijing100191China school of aeronautics Northwestern Polytechnical UniversityXi’an710072China

Clinical experiments have proven that the pedunculopontine nucleus(PPN)plays a crucial role in the modulation of beta oscillations in Parkinson’s disease(PD).Here,we propose a new computational framework by introducing the PPN and related synaptic connections to the classic basal ganglia-thalamo-cortical ***,the improved model can not only simulate the basic saturated and beta activities mentioned in previous studies but also produce the normal alpha rhythm that is much closer to physiological ***,the results show that Parkinsonian oscillation activities can be controlled and modulated by the connection strength between the PPN and the globus pallidus internal nucleus(GPi)and the subthalamic nucleus(STN),supporting the fact that PPN is overinhibited in ***,the internal mechanism underlying these state transitions is further explained from the perspective of ***,both deep brain stimulation(DBS)and optogenetic technology are considered effective in terms of abnormal *** when a low-frequency DBS is added to the PPN,beta oscillations can be suppressed,but it is excited again as the DBS’s frequency gradually increases to a larger *** results coincide with the experimental results that low-frequency stimulation of the PPN is effective,and verify the rationality of the ***,we show that optogenetic stimulation of the globus pallidus external(GPe)expressing excitatory channelrhodopsin(ChR2.can effectively inhibit beta oscillations,whereas exciting the STN and PPN has a limited *** results are consistent with experimental reports suggesting that the symptoms of PD’s movement disorder can be alleviated under the GPe-ChR2.but not STN-ChR2.*** the functional role of the PPN and the feasibility of optogenetic stimulation remain to be clinically explored,the results obtained help us understand the mechanisms of beta oscillations in PD.

关键词： Pedunculopontine nucleus Beta oscillations Optogenetic Deep brain stimulation Parkinson’s disease