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linearized Solution for Rapid Filling of Horizontal Pipe with Entrapped Air

JOURNAL OF ENGINEERING MECHANICS 2020年第11期146卷

作者： Huang, Biao Zhu, David Z. Ningbo Univ Coll Civil & Environm Engn Ningbo 315211 Zhejiang Peoples R China Univ Alberta Dept Civil & Environm Engn Edmonton AB Canada

Rapid filling of a horizontal pipe with an entrapped air pocket has attracted significant attention as overpressurization induced by air compression may cause safety concerns. This study developed a linearized model for a rapidly filling horizontal pipe, by using a Jacobian linearization around the equilibrium point of the nonlinear system. The analytical expressions explicitly show the relationship between the characteristics of pressure oscillation and parameters including the driving head, the length of the water column, the length of the entrapped air pocket, the location of the equilibrium point, and the polytropic exponent. The oscillation frequency increases with the driving head whereas it decreases with the length of the air pocket. The obtained analytical solution compares well with the rigid-column model for a limited range, and it is improved by means of introducing power-law fitting for general cases. The linearization method also can be used in other cases, such as rapid filling in a horizontal pipe with the entrapped air pocket above an initial water layer or in slope/vertical pipes.

关键词： Analytical solution Entrapped air linearized model Pressure transient Rapid filling

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On the Design of Yaw Rate Control via Variable Front-to-Total Anti-Roll Moment Distribution

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2020年第2期69卷 1388-1403页

作者： Ricco, Marco Zanchetta, Mattia Rizzo, Giovanni Cardolini Tavernini, Davide Sorniotti, Aldo Chatzikomis, Christoforos Velardocchia, Mauro Geraerts, Marc Dhaens, Miguel Univ Surrey Guildford GU2 7XH Surrey England Politecn Torino I-10129 Turin Italy Tenneco Automot Europe BVBA B-3800 St Truiden Belgium

In vehicle dynamics, yaw rate control is used to improve the cornering response in steady-state and transient conditions. This can be achieved through an appropriate anti-roll moment distribution between the front and rear axles of a vehicle with controllable suspension actuators. Such control action alters the load transfer distribution, which in turn provokes a lateral tire force variation. With respect to the extensive set of papers from the literature discussing yaw rate tracking through active suspension control, this study presents: i) A detailed analysis of the effect of the load transfer on the lateral axle force and cornering stiffness;ii) A novel linearized single-track vehicle model formulation for control system design, based on the results in i);and iii) An optimization-based routine for the design of the non-linear feedforward contribution of the control action. The resulting feedforward-feedback controller is assessed through: a) Simulations with an experimentally validated model of a vehicle with active anti-roll bars (case study 1);and b) Experimental tests on a vehicle prototype with an active suspension system (case study 2).

关键词： Axles Force Tires Load modeling Suspensions Control systems Feedforward systems Anti-roll moment distribution control load transfer linearized model quasi-static model yaw rate control feedforward feedback

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Dynamics of Separation Points Upon Impact of a Floating Circular Cylinder

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JOURNAL OF APPLIED MECHANICS AND TECHNICAL PHYSICS 2019年第5期60卷 798-804页

作者： Norkin, M. V. Southern Fed Univ Rostov Na Donu 344090 Russia

The two-dimensional problem of vertical separation impact of a circular cylinder under the free surface of a heavy liquid is considered. The problem is studied in a linearized formulation corresponding to low velocities of the body and liquid and taking into account the dynamics of the points of separation of the cavitation zone. A coupled nonlinear problem is formulated, which includes a mixed boundary-value problem of potential theory with one-sided constraints on the surface of the body and an equation defining the law of motion of the cylinder. Examples demonstrating the dynamics of separation points during forced or free cylinder motions are considered. Numerical results obtained using the proposed mathematical model are compared with the results of asymptotic analysis of the initial nonlinear problem for small times.

关键词： ideal incompressible liquid circular cylinder separation impact linearized model dynamics of separation points Froude number cavitation number

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An elementary 1-dimensional model for a solid state lithium-ion battery with a single ion conductor electrolyte and a lithium metal negative electrode

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JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS 2019年 123卷 207-221页

作者： Mykhaylov, M. Ganser, M. Klinsmann, M. Hildebrand, F. E. Guz, I. McMeeking, R. M. Univ Aberdeen Kings Coll Sch Engn Aberdeen AB24 3UE Scotland Robert Bosch GmbH Corp Sect Res & Adv Engn D-70049 Stuttgart Germany Karlsruhe Inst Technol Inst Appl Mat D-76344 Eggenstein Leopoldshafen Germany Univ Calif Santa Barbara Dept Mat Santa Barbara CA 93106 USA Univ Calif Santa Barbara Dept Mech Engn Santa Barbara CA 93106 USA INM Leibniz Inst New Mat Campus D2 2 Saarbrucken Germany

An elementary 1-dimensional model is developed for a solid state lithium-ion battery having a single ion conductor electrolyte, a lithium metal negative electrode and a composite positive electrode. The battery topology is assumed to be of the layered variety, thereby justifying the 1-dimensional formulation. The governing equations for the electrochemical kinetics at the interface between the negative electrode and the electrolyte separator are stated, as are those for ion transport in the electrolyte. The positive electrode is assumed to be a particulate composite of storage material within a matrix of electrolyte. A mixture theory is developed for the positive electrode encompassing ion transport in the electrolyte matrix and storage and unstorage of lithium in the active material subject to electrochemical kinetics at the perimeter of the storage particles. Many simplifying assumptions are made with the advantage of them leading to closed-form or semi-closed-form solutions, including linearization of the equations governing the redox kinetics at interfaces in the battery between electrolyte and active material. An approximation is given for the concentration of lithium in the positive electrode of the battery during discharge, with the details depending on a length scale parameter that depends on the competition between the rate of lithium insertion into/extraction from the storage particles and the rate at which lithium ions are transported in the electrolyte. When the conductivity of the electrolyte is high and the redox reactions are relatively sluggish, this length scale parameter is comparable to the thickness of the positive electrode or larger than it. In that case lithium insertion into/extraction from storage particles occurs everywhere within an active zone of the positive electrode, but with the rates least at the current collector of the positive electrode. If the conductivity of the electrolyte is poor and the redox reactions rapid, the length scale

关键词： Lithium-ion batteries Metal negative electrode Single ion conducting electrolyte Composite positive electrode linearized model

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Generalized Single-Phase Harmonic State Space modeling of the Modular Multilevel Converter With Zero-Sequence Voltage Compensation

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IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS 2019年第8期66卷 6416-6426页

作者： Xu, Zigao Li, Binbin Wang, Shengbo Zhang, Shiguang Xu, Dianguo Harbin Inst Technol Sch Elect Engn & Automat Harbin 150001 Heilongjiang Peoples R China

The modular multilevel converter (MMC) has attracted extensive research in recent years. An appropriate model is necessary to analyze stability or to design MMC controllers. Several published MMC models have been derived in single-phase form to simplify the modeling mathematics. However, little attention is given to the zero-sequence voltage, which introduces coupling in the single-phase model and leads to significant error. In this paper, after revealing the mechanism behind the zero-sequence voltage, a more accurate generalized single-phase MMC model is proposed, which eliminates the zero-sequence voltage coupling effect and is linearized based on harmonic state space (HSS) theory to precisely characterize the internal harmonic features of MMC. A systematic HSS modeling process is presented for both open-loop and closed-loop conditions. And the proposed model is generalized as it can incorporate different control strategy by controller transfer function substitution. Hence it is valuable to analyze MMC stability and dynamics. model effectiveness is verified by simulation results.

关键词： Closed-loop control harmonic state space (HSS) linearized model modular multilevel converters (MMC) single-phase model zero-sequence voltage

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An adaptive resonant controller applied to a linear resonant compressor

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INTERNATIONAL JOURNAL OF REFRIGERATION 2019年 104卷 521-529页

作者： Dainez, Paulo Sergio de Oliveira, Jose Nied, Ademir Fed Inst Sao Paulo IFSP Elect Dept BR-01109010 Sao Paulo SP Brazil Santa Catarina State Univ UDESC Dept Elect Engn BR-89219710 Joinville SC Brazil

In this paper, a current controller for the resonant linear compressor is proposed. The speed waveform is used as reference for the current, which is implemented by an adaptive resonant controller, allowing the compressor to be driven at its mechanical resonance frequency and simultaneously controlling the motor force, so that the piston can be driven very close to the maximum displacement, throughout the compressor operating range, without risk of impact between the piston and the stroke end. The controller is simulated by driving the compressor modeled by the nonlinear gas pressure equation and also by the linearized system, demonstrating the effectiveness of the controller and the equivalence between the two models for the control. (C) 2019 Elsevier Ltd and IIR. All rights reserved.

关键词： Resonant linear compressor Current control Adaptive resonant control linearized model

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Application of ANN and ANFIS techniques for PSS tuning in a multimachine power system 16

Application of ANN and ANFIS techniques for PSS tuning in a ...

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16th International Multi-Conference on Systems, Signals and Devices (SSD)

作者： Kahouli, Omar Alshammari, Badr Dhouib, Bilel Natl Engn Sch Sfax Control & Energies Management CEM Lab Sfax Tunisia Hail Univ Fac Engn Hail Saudi Arabia Jazan Univ Fac Engn Jazan Saudi Arabia

ISBN: (纸本)9781728118208

This paper presents a study of performances evaluation of lead-lag Power System Stabilizers 'PSSs' equipped with adaptive mechanisms performed on the basis of artificial intelligence techniques (neuronal networks, and neuro-fuzzy networks). These adaptive and intelligent PSSs with on-line self-tuned parameters have allowed a good damping of rotoric oscillations for various operating conditions and disturbances. Based on a linearized model of a multimachine power system, an optimized design of lead-lag PSSs has been performed using NSGA-II optimization technique.

关键词： Power System Stabilizers Artificial Neural Network(ANN) AdaptiveNeuro-Fuzzy Inference System (ANFIS) linearized model NSGA-II optimization technique

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Improved VSG Control for Type-IV Wind Turbine Generator Considering Operation Limitations 11

Improved VSG Control for Type-IV Wind Turbine Generator Cons...

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11th Annual IEEE Energy Conversion Congress and Exposition (ECCE)

作者： Sun, Chu Ali, Syed Qaseem Joos, Geza Bouffard, Francois McGill Univ Dept Elect & Comp Engn Montreal PQ Canada OPAL RT TECHNOLOGIES Inc Applicat eXpertise & Elect Simulat Div AXES Montreal PQ Canada McGill Univ Dept Elect & Comp Engn Montreal PQ Canada

ISBN: (纸本)9781728103952

The gradually reduced inertia in powers system due to proliferation of renewable energy resource may lead to larger frequency deviation and change rate and thus fault protection triggering. Type-IV wind turbine generator (WTG) can provide inertia and damping via releasing the rotational energy by adopting virtual synchronous generator (VSG) control. However, the energy stored for inertia emulation depends on its machine side inertia and wind speed. To investigate its impact on inertia and damping emulation, linearized model of VSG-controlled type-IV WTG is established in the present research. It is revealed that lower machine-side inertia and higher wind speed will result in worse frequency response than the ideal VSG. An inverse control block is introduced to mitigate this effect. Supplementary control blocks are also added to limit the power and rotor speed of WTG and help damp the oscillation between synchronous generator and WTG. Comprehensive case studies demonstrated the effectiveness of the proposed control strategy.

关键词： Type-IV wind turbine generator virtual synchronous generator linearized model inverse control power and speed limiting

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Stealth walking with reduced double-limb support phase and its extension to careful legged locomotion

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MULTIBODY SYSTEM DYNAMICS 2018年第4期44卷 421-447页

作者： Asano, Fumihiko Japan Adv Inst Sci & Technol Sch Informat Sci 1-1 Asahidai Nomi Ishikawa 9231292 Japan

Stealth walking is an underactuated walking movement completing in one step for a stable and cautious walk on irregular terrains. The generated gait generally consists of the single- and double-limb support phases;during the former, the leg angles are strictly controlled to follow the desired trajectories to make the forefoot land on the ground stealthily, whereas during the latter, the upper body is controlled to return to the initial state while keeping the vertical ground reaction forces acting on both feet positive. This causes, however, the increase of the step period and deterioration of the energy efficiency. To solve this problem, this paper discusses some methods for achieving high-speed stealth walking based on a reduction of the double-limb support phase. First, a model of an underactuated rimless wheel with an upper body is introduced for analysis. Second, a method for generating a stealth walking gait of the linearized model is proposed, and the instability inherent in the gait is mathematically investigated. Third, two methods for extending the obtained results to the nonlinear model are discussed. Fourth, the method is also extended to generate a careful walking gait on the frictionless road surface;the importance and significance of this study are discussed through investigation of a strict stealth walking.

关键词： Stealth walking Upper body Angular momentum linearized model Frictionless road surface

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Eigenvalue analysis of six-phase synchronous motor for small signal stability

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EPE JOURNAL 2018年第2期28卷 49-62页

作者： Iqbal, Arif Singh, G. K. Adani Inst Infrastruct Engn Dept Elect Engn Ahmadabad Gujarat India Indian Inst Technol Roorkee Dept Elect Engn Roorkee Uttar Pradesh India

The increased application of multiphase (more than three-phase) synchronous motor requires it to be investigated from stability point of view. Therefore, this paper primarily addresses the stability analysis of a six-phase synchronous motor during steady-state operation using eigenvalue criteria from its derived linearized model. Based on the variation of dominant eigenvalues, region of instability is determined under different parametric variation and working conditions. Results establish a preferable method for motor stabilization at its design stage as well as under normal working conditions. Analysis has been carried out by using the approach of Park's (dq0) transformation in MATLAB environment together with some experimental results.

关键词： Six-phase synchronous motor linearized model stability analysis instability boundary

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