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A control parameter analysis method based on a transfer function matrix of hybrid multi-terminal HVDC system with flexible adaptability for different operation modes

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INTERNATIONAL JOURNAL OF ELECTRICAL POWER & ENERGY SYSTEMS 2020年 116卷 105584-000页

作者： Chen, Xinquan Liang, Yuansheng Wang, Gang Li, Haifeng Li, Bingkun Guo, Zhu South China Univ Technol Sch Elect Power Engn Guangzhou 510640 Guangdong Peoples R China China Southern Power Grid Elect Power Res Inst State Key Lab HVDC Guangzhou Guangdong Peoples R China

To achieve better controller performance, the impact of control parameters on the stability and dynamic performance is essential to be clarified mathematically for hybrid multi-terminal HVDC (Hybrid-MTDC) systems considering different operation modes (OMs). In this paper, a generic small-signal model (SSM) is established, which can be modified flexibly for different OMs. Then the SSM can be converted into a transfer function matrix (TF-matrix), which avoids deriving the transfer function separately for each controller of the system, and greatly improves the work efficiency. By inputting a step into the TF-matrix, the time-domain mathematical model for the all system state variables can be obtained, and it is more efficient than iterative solutions of high-order differential equations. To this end, a quantitative control parameter analysis method based on a TF-matrix is proposed. Utilizing the proposed method, a typical Hybrid-MTDC system is investigated, and the results demonstrate the practicality and accuracy of the proposed method.

关键词： Hybrid multi-terminal HVDC system Control parameter analysis method Small-signal model transfer function matrix Operation mode

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PERTURBATION THEORY OF transfer function MATRICES

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SIAM JOURNAL ON matrix ANALYSIS AND APPLICATIONS 2023年第3期44卷 1299-1320页

作者： Noferini, Vanni Nyman, Lauri Perez, Javier Quintana, Maria C. Aalto Univ Dept Math & Syst Anal FI-00076 Aalto Finland Univ Montana Dept Math Sci Missoula MT 59812 USA Aalto Univ Dept Math & Syst Anal POB 11100 FI-00076 Aalto Finland

Zeros of rational transfer function matrices R(lambda) are the eigenvalues of associated polynomial system matrices P(lambda) under minimality conditions. In this paper, we define a structured condition number for a simple eigenvalue lambda(0) of a (locally) minimal polynomial system matrix P(lambda), which in turn is a simple zero lambda(0) of its transfer function matrix R(lambda). Since any rational matrix can be written as the transfer function of a polynomial system matrix, our analysis yields a structured perturbation theory for simple zeros of rational matrices R(lambda). To capture all the zeros of R(lambda), regardless of whether they are poles, we consider the notion of root vectors. As corollaries of the main results, we pay particular attention to the special case of lambda(0) being not a pole of R(lambda) since in this case the results get simpler and can be useful in practice. We also compare our structured condition number with Tisseur's unstructured condition number for eigenvalues of matrix polynomials and show that the latter can be unboundedly larger. Finally, we corroborate our analysis by numerical experiments.

关键词： rational matrix transfer function matrix polynomial system matrix rational eigenvalue problem zeros poles root vectors condition number

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HVAC multivariable system modelling and control

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PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART C-JOURNAL OF MECHANICAL ENGINEERING SCIENCE 2023年第9期237卷 2049-2061页

作者： Touqan, Basim Abdul-Ameer, Alaa Salameh, Muna British Univ Dubai Dubai U Arab Emirates Ajman Univ Ajman U Arab Emirates British Univ Dubai Block 10 & 11 1st & 2nd Floor Dubai 345015 U Arab Emirates

Heating, Ventilation and Air Conditioning (HVAC) is a multivariable process where any alteration with one system input affects most or all of the system's outputs simultaneously. Owing to its comprehensiveness, a readily derived multivariable HVAC mathematical model is selected for this work, mainly a hybrid distributed-lumped parameters model. As the transfer function matrix was not established in the selected HVAC model, it was exclusively developed in this study, using the time domain graphical responses of the chosen model. Based on the developed transfer function matrix, a conceptual two-step approach was followed to control HVAC model performance. The first was decoupling the interactions that affect all the system outputs, and the second was designing proper PID controllers for each decoupled loop similar to those used for single input single output (SISO) systems. A direct Nyquist Array (DNA) multivariable control strategy was used for this purpose and successfully decoupled the HVAC system into three separate (SISO) loops. Three PID controllers afterwards were applied for each decoupled loop. The results showed quite decoupled system outputs with a minor coupling percentage so that any change in a system input only affected the corresponding system output. The output responses are also underdamped with almost zero steady-state error confirming the effectiveness of the selected PID parameters. The values of steady-state responses are obtained in (10-15) s compared with (200-600) s of open-loop response time. However, various overshoot percentages in the responses are encountered but are relatively small, with a short settling time, so they don't affect the thermal comfort of the ventilated volume. System stability using the Nyquist criterion has also been examined and found to satisfy the criterion. The multivariable DNA control technique and the SISO closed-loop PID controllers have shown the capability to suppress external disturbances and restore the syst

关键词： HVAC transfer function matrix multivariable control Direct Nyquist Array loops decoupling

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Analysis of Subsynchronous Control Interaction of a Grid Forming Inverter

Analysis of Subsynchronous Control Interaction of a Grid For...

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IEEE-Power-and-Energy-Society General Meeting (PESGM)

作者： Mitsugi, Yasuaki Baba, Jumpei Univ Tokyo Grad Sch Engn Dept Elect Engn & Informat Syst Tokyo Japan Univ Tokyo Grad Sch Frontier Sci Dept Adv Energy Tokyo Japan

ISBN: (纸本)9798350381849;9798350381832

The grid forming inverter (GFM) is considered a key technology to solve the issues of inverter- based resource (IBR)rich grids. Many previous studies have discussed the advantages of GFM over grid following inverter (GFL), but there has been insufficient discussion on the drawbacks of GFM. In particular, a few studies have discussed subsynchronous control interaction (SSCI) induced by GFM, and the interpretable method for the analysis of SSCI has not been studied yet. This paper introduces the method which applies singular value decomposition (SVD) to evaluate the risk of SSCI occurrence in various grid conditions and operational conditions of GFM. The case studies of the SVD analyses of GFM reveal that the risk of SSCI is greater where GFM is connected to the stiff grid or the power flow between GFM and the grid is less. Finally, experimental tests in the controller hardware in the loop (CHIL) environment are performed to verify the validity of SSCI analysis method proposed in this paper.

关键词： Droop control grid forming inverter hardware in the loop singular value decomposition small signal stability transfer function matrix virtual synchronous generator

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Smart Active Vibration Control System of a Wind Turbine Blade Using Piezoelectric Material 40th

Smart Active Vibration Control System of a Wind Turbine Blad...

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40th Conference and Exposition on Structural Dynamics (IMAC)

作者： Hashemi, Ali Jang, Jinwoo Florida Atlantic Univ Dept Civil Environm & Geomat Boca Raton FL 33431 USA

ISBN: (纸本)9783031054495;9783031054488

Vibration suppression has become one of the major issues in sensitive structures. The active vibration control (AVC) has been widely used in the field of vibration damping in rotary structures. In this article, deriving analytical solution of lateral vibration and active vibration control of a wind turbine (WT) blade are investigated. First, a new semi-analytical solution is developed to obtain the lateral deflection of a wind turbine blade under external loadings. We propose a method to map a wind turbine blade to an Euler-Bernoulli beam with the same conditions, in order to find vibration and dynamic responses of the blade by solving analytical vibration solutions of the Euler-Bernoulli beam. Piezoelectric (PZT) material is used in this research as an actuator-sensor to excite the structures and sense the responses. The governing equations of the beam with piezoelectric patches are derived based on the integration of the piezoelectric transducer vibration equations into the vibration equations of the Euler-Bernoulli beam structure. Finite element model of the wind turbine blade with piezoelectric patches is developed. A unique transfer function matrix is derived. The beam structure is projected to the blade by using a unique transfer function matrix which is derived by exciting the structures and achieving responses. The results obtained from the mapping method are compared with the results achieved from the FE model of the blade. A satisfying agreement has been observed between the results. Next, in order to suppress the transverse vibration of the wind turbine blade, piezoelectric ceramic patches are used as an actuator in combination with linear quadratic regulator (LQR) control system. The obtained results show that the proposed smart control system contains PZT patches and LQR control system is able to efficiently suppress lateral vibration.

关键词： Active vibration control Smart structure Structural dynamic Analytical vibration analysis transfer function matrix Piezoelectric actuator and sensor

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On hybrid dynamical systems of differential-difference equations

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CHAOS SOLITONS & FRACTALS 2024年 187卷

作者： Dassios, Ioannis Vaca, Angel Milano, Federico Aristotle Univ Thessaloniki Thessaloniki Greece Univ Coll Dublin Dublin Ireland

In this paper, we define and study a class of linear hybrid dynamical systems characterized by differential- difference equations. We introduce two operators that facilitate the analysis of these systems and derive explicit formulas for their solutions. We examine the transfer function matrix and characteristic polynomial to assess stability. Our theoretical findings are supported by numerical examples, demonstrating their application in power systems stability analysis. Specifically, we substantiate our theory within the context of power systems stability analysis, incorporating elements of discrete behavior.

关键词： Hybrid dynamical systems Differential-difference equations Stability analysis transfer function matrix Power systems stability

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An experimental study on transfer function estimation using acoustic modelling and singular value decomposition

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JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2021年第5期150卷 3557-3568页

作者： Zhu, Qiaoxi Qiu, Xiaojun Coleman, Philip Burnett, Ian Univ Technol Sydney Fac Engn & IT Ctr Audio Acoust & Vibrat Sydney NSW Australia Univ Surrey Inst Sound & Recording Guildford Surrey England

transfer functions relating sound source strengths and the sound pressure at field points are important for sound field control. Recently, two modal domain methods for transfer function estimation have been compared using numerical simulations. One is the spatial harmonic decomposition (SHD) method, which models a sound field with a series of cylindrical waves;while the other is the singular value decomposition (SVD) method, which uses prior sound source location information to build an acoustic model and obtain basis functions for sound field modelling. In this paper, the feasibility of the SVD method using limited measurements to estimate transfer functions over densely spaced field samples within a target region is demonstrated experimentally. Experimental results with various microphone placements and system configurations are reported to demonstrate the geometric flexibility of the SVD method compared to the SHD method. It is shown that the SVD method can estimate broadband transfer functions up to 3099 Hz for a target region with a radius of 0.083 m using three microphones, and allow flexibility in system geometry. Furthermore, an application example of acoustic contrast control is presented, showing that the proposed method is a promising approach to facilitating broadband sound zone control with limited microphones. (c) 2021 Acoustical Society of America.

关键词： Topics: Harmonic analysis Acoustical properties Architectural acoustics Acoustic modeling simulation and analysis Acoustic signal processing Acoustic transducers transfer function matrix Microphone array Energy efficiency Acoustic ecology

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Long-distance mid-wave infrared super-resolution compressive imaging

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OPTICS AND LASER TECHNOLOGY 2023年 157卷

作者： Jin, Xiao-Peng Xiong, An-Dong Wang, Xiao-Qing Yao, Xu-Ri Liu, Xue-Feng Zhao, Qing Beijing Inst Technol Ctr Quantum Technol Res Sch Phys Beijing 100081 Peoples R China Beijing Inst Technol Sch Phys Key Lab Adv Optoelect Quantum Architecture & Measu Beijing 100081 Peoples R China Chinese Acad Sci Natl Space Sci Ctr Key Lab Elect & Informat Technol Space Syst Beijing 100090 Peoples R China Beijing Acad Quantum Informat Sci Beijing 100193 Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China

Super-resolution imaging (SRI) for mid-wave infrared (MWIR) has attracted increasing attention in recent years due to the expensive price for a large number of pixels MWIR cameras. Investigation of the compressed sensing method can partially improves the resolution. However, the quality of SRI is highly related to the transfer function matrix of the optical system, which is difficult to be accurately measured because of the noise existed in MWIR detection, especially in long-distance systems. In this work, we propose a transfer function matrix calculation method which overcomes the issues of low imaging contrast and signal-to-noise ratio compared with previous studies. And we further establish a long-distance focal plane array-based compressive imaging system with a resolution of two digital micro-mirror device pixels which just satisfies the system diffraction limit. In addition, we achieve the 4 x 4 times super-resolution high-quality reconstruction of long-distance digital and physical objects with only six measurements.

关键词： Compressive imaging Mid-wave infrared Super resolution transfer function matrix Long distance

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Thermoacoustics of multi-burner combustors with plenum and chamber cross-talk

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JOURNAL OF SOUND AND VIBRATION 2022年 520卷 116623-116623页

作者： Yoon, Myunggon Gangneung Wonju Natl Univ Dept Mech Engn Wonju 26403 South Korea

This paper presents a thermoacoustic model in the frequency domain for multi-burner combus-tors composed of multiple plenum-nozzle-chamber modules with cross-talk at both plenums and chambers. The thermoacoustic model is given as a multi-input-multi-output transfer function matrix from heat fluctuation input vector to velocity fluctuation output vector. The discrete rotational symmetry of a multi-burner combustor is exploited to obtain a simple, diagonal transfer function matrix. The resonance equation, whose roots are resonances, is given as a set of scalar equations. The explicit form of the resonance equation reveals how combustor and operating parameters influence the resonances, and which parameters are significant for the longitudinal-azimuthal coupling and the plenum-chamber coupling. The diagonalization also allows us to show constructively that every mode shape is a Bloch wave and those mode shapes can characterize all resonances in terms of longitudinal and azimuthal mode numbers. At a low frequency, the resonance equation can be approximated as biquadratic and quadratic equations for a typical combustor geometry and operating conditions. A bunch of low-frequency resonances, peculiar to multi-burner combustors with cross-talk, are interpreted as azimuthal Helmholtz modes in which plenums/chambers and cross-talk ducts serve as the cavities and necks, respectively. Our combustor model is combined with a diagonal flame transfer function matrix for combustion instability analysis and we develop a set of scalar stability equations whose roots determine combustion instability. This stability equation reveals how combustion instability depends on the combustor geometry and operating parameters. Several numerical examples are presented to validate our thermoacoustic model and theoretical findings.

关键词： Multi-burner combustor Cross-talk Combustion instability Bloch wave transfer function matrix

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A dynamic nonlinear model used for controller design of a 600 MW supercritical circulating fluidized bed boiler-turbine unit

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APPLIED THERMAL ENGINEERING 2022年 212卷

作者： Zhang, Hongfu Gao, Mingming Yu, Haoyang Fan, Haohao Zhang, Jiahui North China Elect Power Univ Sch Control & Comp Engn State Key Lab Alternate Elect Power Syst Renewable Beijing 102206 Peoples R China State Grid Beijing Elect Power Co Beijing 100031 Peoples R China

Large-scale circulating fluidized bed (CFB) power generation units with high steam pressure and temperature have been put into operation in order to obtain high cycle efficiency and less emissions. To ensure the flexible operation of such CFB units, it is necessary to build a model for the design of coordinated control system (CCS). However, few studies focus on modeling of such CFB units. Thus, this work develops a mechanistic dynamic nonlinear model of a large-scale supercritical CFB unit, which is suitable for CCS design because of its relatively low complexity. Firstly, model structure is derived from mass and energy conservation laws, combined with analysis of operational characteristics of a 600 MW supercritical CFB unit. Then, unknown parameters and nonlinear functions in model are identified based on running data by using regression analysis and optimization algorithm. Validation results show that the model has satisfactory accuracy and it can capture essential dynamic characteristics of the unit and nonlinearity of CCS. More importantly, the model accuracy is further improved by proposed variable dynamic parameters and correction of coal quality. After this, transfer function matrix of CCS is derived from dynamic nonlinear model, which can be applied to controller design and simulation analysis.

关键词： Supercritical CFB unit Coordinated control system Dynamic nonlinear model Operational flexibility transfer function matrix

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