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Modified Dynamic Model and Small-signal Stability Analysis for LCC- HVDC systems

CSEE Journal of Power and Energy systems 2025年第2期11卷 750-759页

作者： Chunyi Guo Jiaqing Zhang Shuo Yang Huan Li Chuang Fu State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijing 102206China Electric Power Research Institute China Southern Power Grid State Key Laboratory of HVDCGuangzhouChina

Inaccuracy of modeling for line commutated converter based high voltage direct current (LCC-HVDC) systems will degrade the reliability of small-signal stability analysis results. Taking a practical project as the study system, this paper establishes a modified dynamic model by modifying the current switching function, firing angle calculation and DC voltage calculation. Then, the accuracy of the modified model is verified by a detailed electromagnetic transient (EMT) simulation. Finally, with the modified dynamic model, the impact of the control parameters and AC system strength on the small-signal stability of the overall system is investigated by adopting the eigen-analysis. The results clearly demonstrate that the modified model shows higher accuracy than the original model.

关键词： LCC-HVDC modified dynamic model practical project small-signal analysis

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A High-Power Wave Energy Harvester with Mag-Boost Mechanism 5th

A High-Power Wave Energy Harvester with Mag-Boost Mechanism

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5th International Conference on Vibration and Energy Harvesting Applications, VEH 2024

作者： Tang, Tianyi Li, Yunfei Sun, Lining Liu, Huicong State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China School of Mechanical and Electrical Engineering Jiangsu Provincial Key Laboratory of Advanced Robotics Soochow University Suzhou China

ISBN: (纸本)9789819611904

Ocean wave energy is a widely anticipated new type of renewable energy. However, due to the ultra-low-frequency and random motion characteristics of ocean waves, effectively harnessing it presents a significant challenge. This paper proposes a Mag-Boost mechanism based on the phenomenon that the magnetic torque undergoes a sudden change when the magnetic poles of two magnets are orthogonal. This innovative mechanism, requiring just a trigger below 1 Hz, can stimulate a power-magnet to generate high-frequency oscillation without direct contact. Utilizing this mechanism, a high-power wave energy harvester (WEH) with ultra-low-frequency response capabilities has been developed. Tested on a six-degree-of-freedom platform, the WEH demonstrated a high-output power of 1.44W and a power density of 1.2 kW/m3 at a frequency of 1 Hz and an inclination angle of 30°. The peak open-circuit voltage of the WEH reached 5 V, ensuring a completely independent and stable power supply for wireless temperature and humidity sensors. Furthermore, the Mag-Boost mechanism also shows considerable potential for harvesting other forms of low-frequency environmental energy, including wind, vibration, and human kinetic energy. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.

关键词： Water waves

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A real-time multi-head mixed attention mechanism-based prediction method for tunnel boring machine disc cutter wear

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Science china(Technological Sciences) 2025年第1期68卷 286-307页

作者： Haodi WANG Chengjin QIN Honggan YU Zhinan ZHANG Guoqiang HUANG Zhengyang LIU Chengliang LIU State Key Laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China

In the process of hard rock tunnel excavation,workers often need to enter the tunnel boring machine(TBM)cutterhead at regular intervals to measure cutter ***,this method is time-consuming and *** cutter prediction models primarily rely on geological parameters to predict overall cutter wear before construction,making it challenging to monitor real-time wear at different locations of the cutter and obtain accurate geological *** address these challenges,this paper proposes a multi-head mixed attention mechanism-based method for real-time wear prediction of TBM disc ***,a method of cutter wear normalization to eliminate measurement noise is ***,considering the complex correlation of TBM operating parameters in feature and time dimensions,a new multi-head mixed attention mechanism model is designed to establish the dependency between different features and different moments,to better establish the mapping model between operating parameters and cutter ***,the current cutter wear state can be calculated by accumulating the wear amount of all previous small excavation *** effectiveness of the method is verified by using field data from the Mumbai *** results demonstrate that the method is capable of real-time prediction of front cutter and edge cutter wear on the test set,achieving an average accuracy rate of 95.75%.Moreover,the method can update the cutter wear status after every meter of excavation,which has good real-time *** addition,the average accuracy of cutter wear prediction of the proposed method is 11.75%,10.375%,3.875%,3.625%,1.375%,3.125%,2.25%,and 0.75%higher than that of LSTM,CNN,LSTM-CNN,CACNN,SACNN,MMADNN,MTACNN,and *** summary,this approach offers an accurate prediction of cutter wear state while reducing inspection time and costs and has high application value.

关键词： tunnel boring machine cutter wear estimation multi-head mixed attention mechanism real time

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Novel multi-waypoint planning methods based on intermediate state optimization

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Science china(Technological Sciences) 2025年第3期68卷 179-191页

作者： Xinyu QIN Guangbao ZHAO Zixuan LIAO Chao LIU Zhenhua XIONG State Key Laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai200240China

Multi-waypoint planning is essential for manipulators to execute complex tasks *** requires the manipulator to swiftly traverse designated waypoints while adhering to all the kinematic ***,previous research has not fully exploited the kinematic capabilities of manipulators and has overlooked collision *** address these problems,this paper presents two novel methods called recursive intermediate state optimization(RISO)and overall intermediate state optimization(OISO).RISO decomposes the multi-waypoint planning problem into a sequence of one-waypoint planning tasks,employing a recursive approach to generate feasible solutions *** utilizes an improved whale optimization algorithm(WOA),incorporating multiple iterative processes to perform secondary optimization in high-dimensional space based on the initial value,yielding better *** proposed methods have been validated on a six-degree-of-freedom manipulator platform and compared with several traditional algorithms,as well as the state-of-the-art algorithm,*** results show that RISO outperforms Ruckig in scenarios where computation time is critical,while OISO is better suited for scenarios where trajectory quality is prioritized over ***,the proposed methods can also handle collisions,ensuring the generation of collision-free trajectories.

关键词： multi-waypoint planning intermediate state optimization aerial photography task

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Modelling and experimental investigation of micro-dimpled structures milling with spiral trajectory tool reciprocating motion

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Chinese Journal of Aeronautics 2025年第2期38卷 577-596页

作者： Guangzhou WANG Linjie ZHAO Qi LIU Xiguang LI Yazhou SUN Mingjun CHEN School of Mechatronics Engineering Harbin Institute of TechnologyHarbin 150001China Centre for Precision Manufacturing DMEMUniversity of StrathclydeGlasgow G11XJUK State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China

To mill fine and well-defined micro-dimpled structures,a machining manner of spiral trajectory tool reciprocating motion,where the tool repeats the process of‘feed milling–retract–cutting feed–feed milling again’along the spiral trajectory,was *** the kinematics analysis,it is found that the machining quality of micro-dimpled structures is highly dependent on the machining trajectory using spiral trajectory tool reciprocating *** reveal this causation,simulation modelling and experimental studies were carried out.A simulation model was developed to quantitatively and qualitatively investigate the influence of the trajectory discretization strategies(constant-angle and constant-arc length)and parameters(discrete angle,discrete arc length,and pitch)on surface texture and residual height of micro-dimpled ***,micro-dimpled structures were milled under different trajectory discretization strategies and parameters with spiral trajectory tool reciprocating motion.A comprehensive comparison between the milled results and simulation analysis was made based on geometry accuracy,surface morphology and surface roughness of milled ***,the errors and factors affecting the above three aspects were *** results demonstrate both the feasibility of the established simulation model and the machining capability of this machining way in milling high-quality micro-dimpled *** trajectory tool reciprocating motion provides a new machining way for milling micro-dimpled structures and micro-dimpled functional *** an appropriate machining trajectory can be generated based on the optimized trajectory parameters,thus contributing to the improvement of machining quality and efficiency.

关键词： Tool reciprocating motion Spiral trajectory Micro-dimpled structure Micromachining Simulation modelling with diamond tool Surface texture

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Self-powered Smart Water Meter for Pipeline Flow Monitoring 5th

Self-powered Smart Water Meter for Pipeline Flow Monitoring

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5th International Conference on Vibration and Energy Harvesting Applications, VEH 2024

作者： Mei, Mingqi Wang, Zizhao Li, Yunfei Tang, Tianyi Liu, Huicong School of Mechanical and Electric Engineering Jiangsu Provincial Key Laboratory of Advanced Robotics Soochow University Suzhou215123 China State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin150001 China

ISBN: (纸本)9789819611904

This paper presents the development of a water flow energy harvester (WFEH) designed to power smart water meters within residential piping systems. Utilizing the kinetic energy of flowing water, the device harnesses this energy and converts it into electricity via electromagnetic principles. The impeller's shape, quantity, and guide vane height at the inlet were simulated using computational fluid dynamics (CFD) software, comparing impeller rotational speeds under various simulation parameters to select the appropriate impeller configuration. Experimental data indicate that with an inlet water pressure of 0.12 MPa and an outlet pressure of 0.06 MPa, a single coil in the device generates a peak voltage of 3.6 V, with a peak power of 54.2 mW and a head loss of 6 m. The maximum head loss permitted in residential water pipes is 10 m. The energy generation module of the WFEH has been designed with a six-coil array, significantly enhancing its performance output. Theoretically, the output power of the WFEH is sufficient to meet the energy needs of smart water meters. Therefore, the WFEH holds potential for integration into urban water management systems, providing a stable energy supply for data collection and transmission, and contributing to the development of self-powered smart meters. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.

关键词： Water meters

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Automated Force Curve Methods Based Micropipette Force Sensors

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IEEE Transactions on Nanotechnology 2025年 24卷 224-230页

作者： Shi, Huiyao Tang, Si Shi, Jialin Yu, Peng Yang, Tie Su, Chanmin Liu, Lianqing State Key Laboratory of Robotics Shenyang Institute of Automation Shenyang110016 China University of the Chinese Academy of Sciences Beijing100049 China

Force curve is the most important techniques for accurate measuring the stiffness, adhesion and energy dissipation. However, due to the challenges of probe-cell localization, this type of single-cell analysis tool has become a labor-intensive and time-consuming procedure. Here, we demonstrate an automatic positioning methods based on micropipette for force curves acquisition. The automation covers the detection of cells in label-free images, pre-positioning and automatic focusing of micropipette, as well as automated force curves. This new method discards silicon-based probes used in traditional AFM, and instead utilizing a transparent micropipette with an unobstructed tip as the sensor. This advancement enables accurate localization of the probe tip and cell under an optical microscope. Furthermore, during the probe positioning process, we have implemented a pre-localization method using focused laser projection. This allows for manual adjustment of the probe tip within a range of 70 micrometers, providing precise region of interests (ROI) for automatic tip focusing. Combining with the aforementioned techniques. We also demonstrate the high-precision localization and force curve acquisition of eight fixed cells on a single image. The measurement results indicate that the positioning error will not exceed 3.4 μm. Our work has effectively enhanced the efficiency of cellular mechanical measurements and holds the potential to achieve automated high-throughput single-cell analysis and drug screening. © 2002-2012 IEEE.

关键词： Probes

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Cooperative Control of FFM-CSC Using Positive and Negative Trigger Angle for Offshore Wind Power Transmission

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IEEE Transactions on Power Delivery 2025年第3期40卷 1574-1586页

作者： Feng, Dingteng Xiong, Xiaoling Yao, Chenhao Zhou, Zihan Zhao, Chengyong State Key Laboratory of Alternate Electrical Power System With Renewable Energy Sources Beijing102206 China

The current source converter (CSC) is a competitive solution for offshore wind grid integration. The fundamental frequency modulation-based current source converter (FFM-CSC) effectively solves the shortcomings of pulse width modulation CSC (PWM-CSC), in which DC voltage ripple is drastic and electrical stresses are high. The independent control of offshore AC voltage and frequency requires two degrees of control freedom for the converter. Nevertheless, this is not possible for the FFM-CSC since it has single control degree of freedom. To solve this problem, a positive and negative trigger angle cooperative control method is developed for CSC-HVDC connected offshore wind farms. The positive and negative trigger angles of the high and low valves are adopted to stabilize the offshore AC grid and achieve independent control of voltage amplitude and frequency. Next, by exploring the monotonicity of the offshore voltage amplitude and frequency, the laws affecting the control objectives were analyzed. Then, the AC fault characteristics are analyzed, whilst the ride-through methods are investigated accordingly. Finally, experimental prototypes and simulation models are built to confirm the designed control strategy and fault ride-through mechanism. © 1986-2012 IEEE.

关键词： Voltage control Wind power generation Wind farms Reactive power Valves Power system stability Filters Rectifiers Frequency modulation Frequency control

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Model and Data Hybrid Driven Approach for Quantifying the Meteorology-Dependent Demand Flexibility of Building Thermal Loads

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CSEE Journal of Power and Energy systems 2025年第1期11卷 394-405页

作者： Bo Hu Xin Cheng Changzheng Shao Tao Niu Chunyan Li Yue Sun Wei Huang Kaigui Xie State Key Laboratory of Power Transmission Equipment and System Security Chongqing UniversityChongqing400030China

Recently, the heat and electricity integrated energy system (HE-IES) has become a hot topic in both industry and academia. In the HE- IES, the potential flexibility of the buildings' thermal loads can be exploited to relax the heat power balance constraints and consequently allow a more flexible operation of the combined heat and power units. In this paper, model-driven and data-driven techniques are combined to quantify the demand flexibility of the buildings' thermal loads in a non-instructive way. First, the explicit analytical equivalent thermal parameter (ETP) model of the aggregated buildings is developed. The heat transfer coefficient (k) and thermal inertia coefficient (C) of the ETP model are designated to measure the potential demand flexibility. Second, the Particle Swarm Optimization optimized Radial Basis Function neural network (PSO-RBF) is used to identify the relationship between the values of k and C and the meteorological factors. To obtain the training data, an innovative two-stage regression method based on the adaptive temporal resolution is proposed to extract k and C values from the historical thermal load data. Finally, a flexible thermal load model is built based on the predictions of the meteorological factors, which can be conveniently incorporated into the online dispatch of the HE-IES. A comprehensive simulation environment is designed to verify the accuracy and availability of the proposed technique.

关键词： Flexibility of buildings'thermal loads heat and electricity integrated energy system meteorological factors model and data hybrid driven

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Characteristic model-based control of aerial manipulator for improved interaction stability

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Science china(Technological Sciences) 2025年第4期68卷 166-178页

作者： Bingkai XIU Zhan LI Yipeng YANG Huijun GAO Research Institute of Intelligent Control and Systems Harbin Institute of TechnologyHarbin150001China State Key Laboratory of Robotics and Systems(HIT) Harbin Institute of TechnologyHarbin150001China

Maintaining contact stability is crucial when the aerial manipulator interacts with the surrounding environment. In this paper, a novel output feedback framework based on a characteristic model is proposed to improve the contact stability of the aerial manipulator. First, only position measurements of the aerial manipulator are introduced to design the practical finite-time command filter-based force observer. Second, an attitude control architecture including characteristic modeling and controller design is presented. In the modeling part, input-output data is utilized to build the characteristic model with fewer parameters and a simpler structure than the traditional dynamic model. Different from conventional control methods, fewer feedback values,namely only angle information, are required for designing the controller in the controller part. In addition, the convergence of force estimation and the stability of the attitude control system are proved by the Lyapunov analysis. Numerical simulation comparisons are conducted to validate the effectiveness of the attitude controller and force observer. The comparative results demonstrate that the tracking error of x and θ channels decreases at least 10.62% and 10.53% under disturbances and the force estimation precision increases at least 45.19% in the different environmental stiffness. Finally, physical flight experiments are conducted to validate the effectiveness of the proposed framework by a self-built aerial manipulator platform.

关键词： aerial manipulator interaction stability contact force observer characteristic model

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