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An open-loop system design for deep space signal processing applications

ACTA ASTRONAUTICA 2018年 147卷 259-272页

作者： Tang, Jifei Xi, Lanhua Mahapatra, Rabi Hangzhou Dianzi Univ Sch Commun Engn Hangzhou Zhejiang Peoples R China Texas A&M Univ Dept Comp Sci College Stn TX 77843 USA

A novel open-loop system design with high performance is proposed for space positioning and navigation signal processing. Divided by functions, the system has four modules, bandwidth selectable data recorder, narrowband signal analyzer, time-delay difference of arrival estimator and ANFIS supplement processor. A hardware-software co-design approach is made to accelerate computing capability and improve system efficiency. Embedded with the proposed signal processing algorithms, the designed system is capable of handling tasks with high accuracy over long period of continuous measurements. The experiment results show the Doppler frequency tracking root mean square error during 3 h observation is 0.0128 Hz, while the TDOA residue analysis in correlation power spectrum is 0.1166 rad.

关键词： open-loop system Narrowband signal tracking TDOA estimation Intelligent signal processing SW-HW co-design

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open-loop control system of liquid level in double tank cascade system 22

Open-loop control system of liquid level in double tank casc...

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22nd International Conference on Methods and Models in Automation and Robotics (MMAR)

作者： Kula, Krzysztof S. Gdynia Maritime Univ Dept Ship Control Gdynia Poland

ISBN: (纸本)9781538624029

This paper presents the control system of water level in double tank system with free flow, which uses in its structure a nonlinear model of the plant taking into account the dependence of the time constants on the value of the controlled variable. A model that reflects the properties of an object and is a part of the controller allows significant to shorten the settling time if the liquid is regulating in the upper regions of the tank.

关键词： automatic control open-loop system inverse dynamics control linearization models

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Parametric analysis on the transient two-phase wellbore model applied to the Yangyi high-temperature geothermal field

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GEOTHERMAL ENERGY 2025年第1期13卷 1-26页

作者： Chen, Chaofan Zhou, Hongwei Nagel, Thomas Renaud, Theo Naumov, Dmitri Kolditz, Olaf Shao, Haibing China Univ Min & Technol Beijing Sch Energy & Min Engn Beijing 100083 Peoples R China Tech Univ Bergakad Freiberg Geotech Inst D-09599 Freiberg Germany UFZ Helmholtz Ctr Environm Res Dept Environm Informat Permoserstr 15 D-04318 Leipzig Germany Univ Auckland Dept Engn Sci Auckland 92019 New Zealand Tech Univ Dresden Fac Environm Sci D-01069 Dresden Germany

PurposeIn high-temperature geothermal fields, interpretation of the dynamic two-phase state inside the production wells under different wellhead conditions are important to effectively use the geothermal heat source. Therefore, the corresponding wellbore models must have the capability to simulate transient flow and energy state in geothermal wellbores, as well as advective and conductive heat and mass interactions with surrounding *** this study, a transient two-phase wellbore model is developed and implemented in the open source software openGeoSys, to simulate both flow and energy state in the wellbore, as well as advective and conductive heat and mass interactions with surrounding formation. The model is first verified against analytical solutions and numerical results from the open-source simulator FloWell. The model is then further validated with well logging data from the Yangyi geothermal field in Tibet, *** on the simulation results of the parametric analysis, the conductive heat loss of the high-velocity geothermal production well in the Yangyi geothermal field is found to be limited and the influence can be safely neglected after 8 h of discharge. The flash point location in the wellbore moves upwards for 112 m along with the decrease in fluid enthalpy by 200 kJ/kg. In the wellbore shut-in process, the wellhead pressure decreases with decreasing velocity, while the location of the flash point does not change much. After wellbore shut-in, a two-phase state still exists in the closed wellbore, and the temperature profile is dominated by conductive heat exchange with the surrounding formation. Taking into account the impact of the feed zone, the mass flow rate of the ZK203 well in the Yangyi geothermal field increases from 122.87 to 126.26 t/h when the wellhead pressure decreases from 1.26 to 1.18 *** open-source two-phase wellbore model developed and implemented in this work provides preliminary insights into the

关键词： Geothermal wellbore model Two-phase flow open-loop system Transient state Yangyi geothermal field openGeoSys

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open-loop Approach for Robust Detection of Selective Harmonic in Single-Phase system

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IEEE TRANSACTIONS ON INDUSTRIAL INFORMATICS 2019年第12期15卷 6260-6269页

作者： Reza, Md. Shamim Hossain, Md Maruf Ghias, Amer M. Y. M. Bangladesh Univ Engn & Technol Dept Elect & Elect Engn Dhaka 1205 Bangladesh Univ Wisconsin Dept Elect Engn Technol Green Bay WI 54311 USA Nanyang Technol Univ Sch Elect & Elect Engn Singapore 639798 Singapore

This paper proposes an open-loop approach for selective harmonic detection from the single-phase power system under changeable frequency environment. It consists of a frequency tracking algorithm relying on a fixed tuned demodulation method and a selective harmonic detection scheme based on an adaptively tuned cascaded delayed signal cancellation (CDSC) strategy. It can be easily arranged to detect one or several harmonic(s) from the input signal contaminated by different harmonics. The open-loop configuration makes the proposed technique robust, free of interdependent loop, easy tuning, and unconditionally stable. The real-time utilization of trigonometric and inverse trigonometric functions is also avoided in the technique. When compared with the discrete Fourier transform and CDSC-based technique reported in the technical literature, it demands less computational effort and can create faster dynamics and better steady-state accuracy in the estimated frequency. The usefulness of the technique is confirmed by simulation and real-time experimental results.

关键词： Cascaded delayed signal cancellation (CDSC) demodulation method frequency estimation open-loop system selective harmonics

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Self-tuning regulator adaptive controller design for DC-DC boost converter with a novel robust improved identification method

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IET POWER ELECTRONICS 2022年第13期15卷 1365-1379页

作者： Mollaee, Hasan Ghamari, Seyyed Morteza Khavari, Fatemeh Shahrood Univ Technol Dept Elect & Robot Engn Shahrood Iran

The design of a self-tuning regulator adaptive controller is presented for Boost converter using Pulse Width Modulation, which has been improved in dynamic with a novel Robust Improved Exponential Regressive Least Square identification scheme. Regarding the negative influences of harmful disturbances on the converters, the Minimum Degree Pole Placement technique is designed using an adaptive mechanism with an online identification technique, which is simple in structure and can provide more accurate parametric estimation and better efficiency in challenging situations, particularly against noise. Based on the right half-plane zero structure of the Boost converter, the open-loop system is called a non-minimum phase system which creates some challenging constraints for the controller design. The primary objective of designing a feedback loop controller is to ensure the stability of the system and appropriate regulation within a pre-determined range of operating conditions. This controller considers the system as a black-box structure;thus, the mathematical model of the system is not needed. This benefit can decrease the computational burden, and provides faster dynamics along with ease of implementation. Finally, the strength of this control strategy is tested by experimental and simulation results in different conditions.

关键词： DC-DC boost converter pole assignment PWM power convertors open loop systems feedback loop controller black-box structure online identification feedback nonminimum phase system pulse width modulation DC-DC power convertors control system synthesis adaptive mechanism adaptive control least squares approximations parametric estimation parameter estimation self-adjusting systems robust control open-loop system stability regression analysis half-plane zero structure minimum degree pole placement robust improved exponential regressive least square identification self-tuning regulator adaptive controller design

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Grid Synchronization Techniques: A Review

Grid Synchronization Techniques: A Review

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International Conference on Advancement in Materials, Manufacturing and Energy Engineering, ICAMME 2021

作者： Gawhade, Pragya Ojha, Amit MANIT Bhopal India

ISBN: (纸本)9789811653704

Recently, grid synchronization attracts large concern due to the integration of renewable energy sources with the power utility grid. In order to remain interconnected while maintaining grid stability, an appropriate control technique is needed. Various RES are synchronized by monitoring grid voltage, frequency, and phase to ensure proper operation. Over the year, various grid synchronization techniques have been presented to address problems like variation in frequency and unbalanced grid condition. In recent years, grid-tied photovoltaic system has become prominent with its reliability, simplicity, and endurability. This paper includes a review of past studies on grid-connected converter synchronization techniques. The basic structure of the phase-locked loop (PLL) with grid synchronization methods for 1-phase and 3-phase is discussed in brief. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Close-loop system Grid synchronization open-loop system Phase-locked loop

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L²-Well-posedness and Regularity of 1-d Wave Equations on a Three-edge-tree-shaped Network 40

<i>L</i><SUP>2</SUP>-Well-posedness and Regularity of 1-d Wa...

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40th Chinese Control Conference (CCC)

作者： Liu, Dongyi Qi, Qi Xu, Genqi Tianjin Univ Sch Math Tianjin 300350 Peoples R China

ISBN: (纸本)9789881563804

This paper concerns the input-output L2-well-posedness and regularity of 1-d wave equations on a three-edge-tree-shaped network. The well-posedness of open-loop network system is verified by constructing appropriate multiplies. In light of an approximate estimation of the input-output transfer function of system, it is shown that the open-loop system is regular.

关键词： 1-d Wave Equation open-loop system L2-Well-posedness Regularity Tree-shaped Network Multiplier Method

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Prediction-based sliding mode control of non-linear systems with input delay using disturbance observer

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IET CONTROL THEORY AND APPLICATIONS 2019年第13期13卷 2047-2055页

作者： Moosapour, Seyed Hamze Ataei, Mohammad Ekramian, Mohsen Univ Isfahan Dept Elect Engn Fac Engn Esfahan Iran

In this study, stabilisation of input-delay non-linear systems in the presence of disturbance based on prediction variable is studied. For both disturbance estimation and delay compensation, an extended prediction variable as well as adaptive sliding mode controller are proposed in which the open-loop system is not required to be stable. In the proposed prediction variable one needs to estimate disturbance in the future. In order to solve this problem a new non-linear disturbance observer (NDOB) is proposed. Considering the NDOB in the closed-loop system, the stability analysis of error dynamic is performed. And the asymptotic stability of non-linear system with input delay is guaranteed for some class of disturbance. Simulation results finally validate the good performance and robustness of the proposed controller based on disturbance observer.

关键词： linear systems stability nonlinear control systems variable structure systems asymptotic stability observers control system synthesis adaptive control robust control delays closed loop systems delay compensation extended prediction variable adaptive sliding mode controller open-loop system nonlinear disturbance observer closed-loop system nonlinear system input delay prediction-based mode control input-delay nonlinear systems disturbance estimation

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L2-Well-posedness and Regularity of 1-d Wave Equations on a Three-edge-tree-shaped Network

L2-Well-posedness and Regularity of 1-d Wave Equations on a ...

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第40届中国控制会议

作者： Dongyi Liu Qi Qi Genqi Xu School of Mathematics Tianjin University

This paper concerns the input-output L-well-posedness and regularity of 1-d wave equations on a three-edge-treeshaped network. The well-posedness of open-loop network system is verified by constructing appropriate multiplies. In light of an approximate estimation of the input-output transfer function of system, it is shown that the open-loop system is regular.

关键词： 1-d Wave Equation open-loop system L2-Well-posedness Regularity Tree-shaped Network Multiplier Method

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Geothermal energy from flooded mines: Modeling of transient energy recovery with thermohaline stratification

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ENERGY CONVERSION AND MANAGEMENT 2019年 199卷 111956-000页

作者： Bao, Ting Liu, Zhen (Leo) Michigan Technol Univ Dept Civil & Environm Engn 1400 Townsend DrDow 854 Houghton MI 49931 USA Michigan Technol Univ Dept Civil & Environm Engn 1400 Townsend DrDillman 201F Houghton MI 49931 USA Cent S Univ Minist Educ Key Lab Metallogen Predict Nonferrous Met & Geol 932 Lushan S Rd Changsha 410083 Hunan Peoples R China

Geothermal energy from flooded mines is a high-potential clean energy resource that can provide heating to large communities with power comparable to small-scale power plants. The transient energy recovery process for utilizing this energy resource, however, has not been well understood, especially those involving the heat transfer in mine water with the widely-observed layering phenomenon where the temperature and salinity are stratified. To better understand the transient energy recovery process considering such a layering phenomenon, this study presents a numerical analysis of transient heat extraction from a flooded mine shaft with mine water dominated by thermohaline stratification. The numerical analysis is conducted based on a realistic case using an open-loop heat pump system. The simulation results show that, when normal pumping rates are used, the water temperature available to heat pumps almost keeps unchanged because the transient energy recovery using an open-loop system only leads to a temperature reduction of 0.2-0.3 K. By comparison, the simulation results in this study are consistent with those measured from real demonstration projects, showing the accuracy of the simulations and confirming the high efficiency and reliability of this energy innovation. The modeling results in this study also reveal that heat extraction does not affect the stability of thermohaline stratification when normal pumping rates, e.g.,0.0014-0.03 m(3)/s, are adopted, but will break thermohaline stratification with pumping rates over a hundred times of the commonly-used ones. These findings provide guidelines for future applications at different scales, and the methodology reported in this study can be used to assist the design of the energy recovery systems.

关键词： Mine water Thermohaline stratification stability Heat extraction Pumping rate open-loop system

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