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A modified lumped parameter model of distribution transformer winding

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Global Energy Interconnection 2020年第2期3卷 158-165页

作者： Qingqing Ding Yao Yao Bingqian Wang Jingwei Fu Wei Zhang Chao Zeng Xiaoping Li Stanimir Valtchev State Key Laboratory of Power System Department of Electrical EngineeringTsinghua UniversityHaidian DistrictBeijing100084P.R.China State Grid Hubei Electric Power Co. Research Institute(HBEPRI)Hongshan DistrictWuhan 430077P.R.China Flexible Transmission Engineering Department Nari-Relays Electric Company210003 NanjingP.R.China State Grid Hubei Electric Power Co. LtdHongshan District430077 WuhanP.R.China Department of Electrical and Computer Engineering Faculty of Science and TechnologyUNLPortugal

The modelling of the distribution transformer winding is the starting point and serves as important basis for the transformer characteristics analysis and the lightning pulse response prediction.A distributed parameters model can depict the winding characteristics accurately,but it requires complex calculations.lumped parameter model requires less calculations,but its applicable frequency range is not wide.This paper studies the amplitude-frequency characteristics of the lightning wave,compares the transformer modelling methods and finally proposes a modified lumped parameter model,based on the above comparison.The proposed model minimizes the errors provoked by the lumped parameter approximation,and the hyperbolic functions of the distributed parameter model.By this modification it becomes possible to accurately describe the winding characteristics and rapidly obtain the node voltage response.The proposed model can provide theoretical and experimental support to lightning protection of the distribution transformer.

关键词： Wide band frequency response Distributed parameter model lumped parameter model Distribution transformer Lightning protection

Optimal measurement locations for diagnosis of aortic abnormalities in a lumped-parameter model of the systemic circulation using sensitivity analysis

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International Journal of Biomathematics 2017年第8期10卷 217-240页

作者： R. Gul S. Bernhard Department of MathematicsCOMSATS Institute of Information Technology Abbottabad Pakistan Department of Electrical Engineering and Information Technology Pforzheim University of Applied Sciences Germany

The basic theme of this work is to identify the optimal measurement locations for pressure and flow in the systemic circulation to detect aortic stenoses and aneurysms in early stages of a disease. For this purpose, a linear elastic lumped parameter model of the fluid dynamical simulator, major arterial cardiovascular simulator (MACSim), is considered and global sensitivity analysis is applied to identify the better measurement locations for pressure and flow in the systemic circulation. The obtained results of sensitivity analysis provide insight that enable the experimentalists to optimize their experimental setups for detecting aortic stenoses and aneurysms using parameter estimation process. From the results, it is observed that the stenosis in the thoracic aorta can be identified from both pressure and flow at the location itself, nearby nodes, aorta ascendens, arcus aorta, arteria subclavia and arteria axillaris. On the other hand, the preferable measurement locations for abdominal aneurysms are locations themselves, nearby nodes and left/right leg of the body.

关键词： lumped parameter model systemic circulation stenoses aneurysms global sensitivity analysis

lumped parameter model based surgical planning for CABG

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Medicine in Novel Technology and Devices 2019年第2期2卷 19-25页

作者： Boyan Mao Yue Feng Bao Li Jincheng Liu Yili Feng Youjun Liu College of Life Science and Bio-engineering Beijing University of TechnologyBeijingChina

The current 3D CABG model is time consuming,a lumped parameter CABG model may solve this problem.A coronary lumped parameter model without stenosis and graft was constructed.The stenosis resistance was calculated and graft model was constructed.After calculation,the graft flow results of CABG lumped parameter model fit well with 3D CABG model results.

关键词： Coronary artery bypass grafting(CABG) lumped parameter model Surgical planning Multiscaled model Graft flow

lumped parameter Mass Flow Rate and Pressure Control Characteristics model for High-Speed Pneumatic PWM on/off Valve

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Journal of Donghua University(English Edition) 2014年第3期31卷 293-303页

作者：向忠胡旭东刘昊汝晶炜 Faculty of Mechanical Engineering & Automation Zhejiang Sci-Tech University State Key Laboratory of Fluid Power Transmission and Control Zhejiang University

Aiming at solving the problem of strong coupling characteristic of the key parameters of high-speed pneumatic pulse width modulation( PWM) on / off valve, a general lumped parameter mathematical model based on the valves time periods was well developed. With this model,the mass flow rate and dynamic pressure characteristics of constant volumes controlled by high-speed pneumatic PWM on /off valves was well described. A variable flow rate coefficient model was proposed to substitute for the constant one used in most of the prior works to investigate PWM on /off valves' dynamical pressure response, and a formula for disclosing the inherent relationship among the PWM command signal,static mass flow rate,and sonic conductance of the valve was newly derived.Finally,an extensive set of analytical experimental comparisons were implemented to verify the validity of the proposed mathematica model. With the proposed model, PWM on /off valves' characteristics,such as mass flow rate,step pressure response of the valve control system,mean pressure and ripple amplitude,not only in the linear range,but also in the nonlinear range can be wel predicted; Good agreement between measured and calculated results was obtained,which proved that the model is helpful for designing a control strategy in a closed loop control system.

关键词： lumped parameter model pneumatic on/off valve pulse width modulation(PWM) mass flow rate pressure characteristic

Study on excitation force characteristics in a coupled shaker-structure system considering structure modes coupling

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Chinese Journal of Aeronautics 2022年第7期35卷 227-245页

作者： Guiwei ZHANG Xiaochen WANG Zhichun YANG School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China

The interaction between an elastic structure and electrodynamic shakers commonly exists in Ground Flutter Simulation Tests(GFST)with multi-point excitations,causing a considerable discrepancy between the practical excitation forces and desired ones.To investigate the excitation force characteristics on a cantilever beam excited by a voltage-sourced electrodynamic shaker,the coupled shaker-beam system is modeled to derive the excitation force formula using Hamilton’s principle and Galerkin’s approach.Simulation results using the multi-mode beam model coupled with the shaker model are in good agreement with experimental results,verifying that the proposed multi-mode method can accurately predict the excitation force.Furthermore,parametric studies show that the influence of system parameters on the excitation force is related to the shaker’s operating mode.Unlike in current mode of shaker,when the beam resonant frequency approaches the suspension frequency of shaker armature,the variation of excitation force amplitude in voltage mode is no longer minimal.Meanwhile,if the exciting point in the GFST is located far away from the modal node,it is essential to compensate the force because the accuracy of tests can be reduced dramatically.The coupled shaker-beam model proposed in this paper can provide the basis for compensation measures.

关键词： Electrodynamic shaker Force characteristics Galerkin’s approach lumped parameter model parameters estimation

INVESTIGATION ON EFFECT OF DRUG DOSING REGIMENTS ON DRUG DELIVERY IN SOLID TUMOR VIA lumped parameter modelING AND ANIMAL EXPERIMENTS

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Journal of Hydrodynamics 2009年第1期21卷 20-25页

作者： GAO Ci-xiu XU Shi-xiong JIANG Yu-ping TU Jiang-long Department of Mechanics and Engineering Science Fudan University Shanghai 200433 China Huashan Hospital attached to Fudan University Shanghai 200040 China Jiangxi Medical School Nanchang 330006 China

This work aims to investigate the effects of dosing regiments on drug delivery in solid tumors and to validate them with experiments on rats. The lumped parameter models of pharmacokinetics and of drug delivery in tumor were developed to simulate time courses of average drug concentration （Ct） of tumor interstitium in two types of dosing regiments （i.e., single-shot and triple-shot ones）. The two regiments were performed via antitumor drug, hydroxycamptothecin （HCPT）, on rats, to measure the drug concentration in the tumor. The simulations of the drug concentration in the tumor of the two dosing regiments were conducted and compared with the experimental data on rats. The coefficients in the models were investigated. It is concluded that the triple-shot method is more effective than that of single-shot injection. The present lumped-parameter model is quantitatively competent for drug delivery in solid tumor.

关键词： solid tumor dosing regiments lumped parameter model experiment on rats

A framework for rapid on-board deterministic estimation of occupant injury risk in motor vehicle crashes with quantitative uncertainty evaluation

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Science China(Technological Sciences) 2021年第3期64卷 521-534页

作者： BANCE Iason YANG SaiChao ZHOU Qing LI ShengBo NIE BingBing State Key Laboratory of Automotive Safety and Energy School of Vehicle and MobilityTsinghua UniversityBeijing 100084China

Accurate on-board occupant injury risk prediction of motor vehicle crashes(MVCs)can decrease fatality rates by providing critical information timely and improving injury severity triage rates.The present implemented prediction algorithms in vehicle safety systems are probabilistic and rely on multi-variate logistic regression of real-world vehicle collision databases.As a result,they do not utilize important vehicle and occupant features and tend to overgeneralize the solution space.This study presents a framework to address these problems with deterministic and computationally efficient lumped parameter model simulations driven by a database of vehicle crash tests.A 648-case mixed database was generated with finite element and multi-body models and validated under the principal directions of impact with experimental results for a single vehicle body type.Using the finite element database,we developed lumped parameter models for four principal modes of impact(i.e.,frontal,rear,near side and far side)with parameters identified via genetic algorithm optimization.To obtain confidence bounds for the injury risk prediction,the parameter uncertainty and model adequacy were evaluated with arbitrary and bootstrapped polynomial chaos expansion.The developed algorithm was able to achieve over triage rates of 17.1%±8.5%,whilst keeping the under triage rates below 8%on a finite element-multi body model database of a single vehicle body type.This study demonstrated the feasibility and importance of using low-complexity deterministic models with uncertainty quantification in enhanced occupant injury risk prediction.Further research is required to evaluate the effectiveness of this framework under a wide range of vehicle types.With the flexibility of parameter adjustment and high computational efficiency,the present framework is generic in nature so as to maximize future applicability in improved on-board triage decision making in active safety systems.

关键词： occupant safety injury prediction lumped parameter model motor vehicle crash uncertainty quantification

modeling and Optimal Design of 3 Degrees of Freedom Helmholtz Resonator in Hydraulic System

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Chinese Journal of Aeronautics 2012年第5期25卷 776-783页

作者： GUAN Changbin JIAO Zongxia School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China Science and Technology on Aircraft Control Laboratory Beihang UniversityBeijing 100191China

Three degrees of freedom （3-DOF） Helmholtz resonator which consists of three cylindrical necks and cavities connected in series （neck-cavity-neck-cavity-neck-cavity） is suitable to reduce flow pulsation in hydraulic system. A novel lumped parameter model （LPM） of 3-DOF Helmholtz resonator in hydraulic system is developed which considers the viscous friction loss of hy- draulic fluid in the necks. Applying the Newton＇s second law of motion to the equivalent mechanical model of the resonator, closed-form expression of transmission loss and resonance frequency is presented. Based on the LPM, an optimal design method which employs rotate vector optimization method （RVOM） is proposed. The purpose of the optimal design is to search the reso- nator＇s unknown parameters so that its resonance frequencies can coincide with the pump-induced flow pulsation harmonics respectively. The optimal design method is realized to design 3-DOF Helmholtz resonator for a certain type of aviation piston pump hydraulic system. The optimization result shows the feasibility of this method, and the simulation under optimum parame- ters reveals that the LPM can get the same precision as transfer matrix method （TMM）.

关键词： structural optimization vibration analysis hydraulic resonator lumped parameter model rotate vector optimizationmethod transmission loss resonance frequency

OPTIMUM DESIGN OF CARS TO CONSIDER COMPATIBILITY

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OPTIMUM DESIGN OF CARS TO CONSIDER COMPATIBILITY