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newton-raphson algorithm-based modified SHE for CHB multilevel inverter control considering capacitor voltage balancing and power factor variation

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INTERNATIONAL TRANSACTIONS ON ELECTRICAL ENERGY SYSTEMS 2019年第12期29卷

作者： Manai, Lazhar Armi, Faouzi Besbes, Mongi Univ Tunis Natl Engn Sch Tunis Lab Robot Informat & Complex Syst Tunis 1002 Tunisia Univ Carthage Higher Inst Informat & Commun Technol Tunis Tunisia

Conventional selective harmonic elimination (SHE) based on newton-raphson (N-R) algorithm is extended to give a modified method that provides more switching angles to eliminate more harmonic order. Modified SHE method is investigated for capacitor voltage balancing in cascaded multilevel inverters considering load power factor variation. Without measuring current and capacitor voltages, as well as not using any controller and voltage feedback, the proposed strategy is capable of determining the best switching angles pattern in low switching frequency to maintain nil mean current capacitor DC-link, hence balancing the capacitor voltage and eliminating certain harmonic orders while considering inverter R,L load power factor variation. Simulation and experimental results prove the efficiency of the proposed control strategy by getting an output voltage with the desired number of levels and balanced capacitor while eliminating more harmonics.

关键词： capacitor voltage CHB multilevel inverter modified selective harmonic elimination newton-raphson algorithm power factor

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Flying Capacitor Multilevel Inverter Control Considering Lower Order Harmonics Elimination Based on newton-raphson algorithm

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ELECTRIC POWER COMPONENTS AND SYSTEMS 2017年第17期45卷 1918-1928页

作者： Manai, Lazhar Armi, Faouzi Besbes, Mongi Univ Tunis Natl Engn Sch Tunis Lab Robot Informat & Complex Syst El Manar Bpn Tunis Tunisia Univ Carthage Higher Inst Informat & Commun Technol Borj Cedria Ind Informat Ben Arous Tunisia

newton-raphson-based flying capacitor multilevel inverter modeling is investigated for capacitor voltage balancing. Without using voltage feedback, newton-raphson method determines the best switching pattern for maintaining nil mean current in all capacitors, hence minimizing the capacitor voltage fluctuation and eliminating certain harmonic orders. Flying capacitor multilevel inverter (FCMI) modeling is developed to work with the selective harmonic elimination (SHE) technique to obtain a programmable pulse generator for multilevel inverter commutation cell control. Theoretical results are verified by experiments and simulations for a flying capacitor four-level inverter. Results show that the proposed method does effectively eliminate a number of specific low order harmonics, and the output voltage is resulted in low total harmonic distortion and with balanced flying capacitors.

关键词： newton-raphson algorithm optimization algorithm switching angles multilevel inverter selective harmonic elimination (SHE) flying capacitor voltage balancing flying capacitor multilevel inverter lower order harmonics total harmonic distortion (THD) erasable programmable read only memories (EPROMS) harmonic minimization

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Forward Kinematics Analysis of the Spindle-Coupled Road Simulator with Modified newton-raphson algorithm

Forward Kinematics Analysis of the Spindle-Coupled Road Simu...

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IEEE International Conference on Information and Automation (ICIA)

作者： Wang, Xiao Zhang, Yanyan Cong, Dacheng Han, Junwei Harbin Inst Technol State Key Lab Robot & Syst Harbin Heilongjiang Peoples R China

ISBN: (纸本)9781538631546

The forward kinematics analysis of the six-degree-of-freedom(DOF) spindle-coupled road simulator (SCRS) with a complex hybrid serial-parallel mechanism(HSPM) has been performed. The forward kinematics with an efficient method is significant for control, singularity and workspace analysis of SCRS. Applying the vector matrix theory, the geometric restriction function was expressed in concise and compact form. A modified newton-raphson algorithm which could guarantee the convergence and improve the rapidity was proposed to solve the problem of the forward kinematics. The validity of forward kinematic formulations was verified through Matlab/Simulink and ADAMS. The numerical results show that the established model is accurate and the algorithm is effective which lays a good foundation for both mechanical system optimization and control scheme design of SCRS.

关键词： Spindle-coupled road simulator Forward Kinematics Vector matrix theory newton-raphson algorithm

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A Novel newton-raphson algorithm for Power Flow Analysis in the Presence of Constant Current Sources

A Novel Newton-Raphson Algorithm for Power Flow Analysis in ...

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IEEE/PES Transmission and Distribution Conference and Exposition (T&D)

作者： Rajaei, N. Ahmed, M. H. Salama, M. M. A. Univ Waterloo Dept Elect & Comp Engn Waterloo ON Canada

ISBN: (纸本)9781509021574

This paper presents a version of the newton-raphson (NR) algorithm that has been modified to provide a means of facilitating the power flow analysis of loop systems in the presence of current sources that rely on current controlled inverters, such as distributed generators (DGs). The modifications entail the inclusion of the current elements of current sources in the Jacobian matrix of the NR algorithm. The effect is to enable current controlled sources to be modeled directly in the power flow algorithms without the need for converting their currents to the corresponding power components, which is the traditional practice in power flow algorithms. The proposed algorithm has been tested on an IEEE 14-bus system. For loop systems with current controlled sources, the test results show that using this algorithm for power flow analysis offers enhanced accuracy.

关键词： newton-raphson algorithm power flow analysis loop systems current sources

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A newton-raphson solution to the exponentially weighted least M-estimate formulation for acoustic system identification

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APPLIED ACOUSTICS 2025年 231卷

作者： Zhang, Limin He, Hongsen Chen, Jingdong Yu, Yi Benesty, Jacob Southwest Univ Sci & Technol Sch Informat Engn & Robot Technol Used Special Env Key Lab Sichuan Prov Mianyang 621010 Peoples R China Nanjing Univ Sch Elect Sci & Engn Nanjing 210023 Peoples R China Northwestern Polytech Univ CIAIC 127 Youyi West Rd Xian 710072 Peoples R China Northwestern Polytech Univ Shaanxi Prov Key Lab Artificial Intelligence 127 Youyi West Rd Xian 710072 Peoples R China Univ Quebec INRS EMT 800 Gauchetiere OuestSuite 6900 Montreal PQ H5A 1K6 Canada

The formulation of the exponentially weighted least M-estimate has shown significant promise in addressing acoustic system identification amidst non-Gaussian noise. A common approach to this formulation is the recursive least M-estimate algorithm. However, due to its derivation from nonlinear normal equations, resulting in a slow approximate solution, this algorithm tends to exhibit poor convergence performance. In this paper, we present a newton-raphson solution, where the cost function is expanded using the second-order Taylor series to establish the adaptive algorithm. This approach bypasses the nonlinear normal equations, yielding a robust solution that more dynamically reflects changes in the cost function, ultimately leading to improved convergence and tracking performance.

关键词： Acoustic system identification Adaptive filter newton-raphson algorithm Robustness

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Defining the possible variants of a sectioned network by using a modified newton-raphson algorithm

Defining the possible variants of a sectioned network by usi...

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IEEE International Energy Conference (ENERGYCON)

作者： Bobetko, Tin Andric, Antun Princip, Mario Croatian Transmiss Syst Operator Ltd Kupska 4 Zagreb Croatia

ISBN: (纸本)9781479924493

Congestions and undesirable power flows are an increasingly common occurrence in transmission networks. One possible measure to eliminate the congestion in network would be changing the network's topology since the stated changes the impedance of the network, which results in a change of power flow. Since the change in network topology has various implications, it can also be used as a powerful tool in optimization techniques resulting in reduction of power system losses, as well as in the already mentioned congestion management. This study deals with a new approach to the problem of changes in network topology based on application of a three-dimensional matrix of admittance, and with automating the process of power flow calculations for all possible variants of the network.

关键词： network topology load flow calculations optimization techniques newton-raphson algorithm

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Investigating the Performance of Steepest Descent, newton-raphson, and Fletcher-Reeves Approaches in Unconstrained Minimization Problems 13

Investigating the Performance of Steepest Descent, Newton-Ra...

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IEEE 13th Annual Computing and Communication Workshop and Conference (CCWC)

作者： Hossain, Mohammad Safayet Simaan, Marwan A. Univ Cent Florida Dept Elect & Comp Engn Orlando FL 32816 USA

ISBN: (纸本)9798350332865

Different optimization approaches are explored to solve unconstrained minimization problems numerically in this paper. A classic optimization problem i.e., the Rosenbrock function is considered a benchmark to compare the performance of multiple algorithms including steepest descent, newton-raphson, and Fletcher-Reeves conjugate gradient. The performance of four methods including fixed step size, variable step size, quadratic fit, and golden section search region elimination with the steepest descent algorithm is investigated also. The required number of iterations to converge the minimum set point while solving problems is considered an evaluation metric. The converging trajectory of the algorithms is presented using level curves.

关键词： unconstrained minimization Rosenbrock function Steepest descent algorithm newton-raphson algorithm Fletcher-Reeves algorithm

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Nonlinear-memoryless-amplification behavior of bi-directional prestressed TMD for integrated vibration control of offshore wind turbine

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NONLINEAR DYNAMICS 2024年第23期112卷 20941-20965页

作者： Liu, Gang Lei, Zhenbo Yang, Qingshan Law, S. S. Cong, Yu Wang, Tao Chongqing Univ Key Lab New Technol Construction Cities Mt Area Minist Educ Chongqing 400045 Peoples R China Chongqing Univ Sch Civil Engn Chongqing 400045 Peoples R China Univ Paris Saclay Univ Evry LMEE F-91020 Evry France Harbin Inst Technol Sch Transportat Sci & Engn Harbin 150040 Heilongjiang Peoples R China

An improved pendulum tuned mass damper with nonlinear cable tension, known as the prestressed tuned mass damper (PSTMD), has been proposed and investigated for mitigating excessive vibrations of offshore wind turbines (OWTs) across a frequency range. Unlike conventional nonlinear TMDs constructed with nonlinearity springs or dampers, the nonlinearity in the PSTMD originates from the geometric properties of its prestressing cables. This study extends the development of the device to a bi-directional PSTMD, considering the distinct nonlinear-memoryless-amplification (NMA) behavior for integrated vibration control in an OWT system, by means of the theoretical analysis and numerical simulation approaches. A mathematical model is derived to describe the nonlinear tensile forces of the cables in the bi-directional PSTMD, and a dynamical nonlinear model of the OWT with proposed PSTMD is established to account for aero-hydrodynamic loadings. NMA dynamic behavior under harmonic loads is examined via using the newton-raphson algorithm to explore the integrated vibration control of bi-directional PSTMD under wind-wave loads. Numerical simulations are conducted to demonstrate the effectiveness of the nonlinear bi-directional PSTMD in suppressing vibrations of the OWT system under both harmonic and wind-wave excitations. The analysis results indicate that the bi-directional PSTMD, considering the NMA behavior, effectively mitigates the frequency detuning phenomenon at the natural frequency of the OWT system. Furthermore, the study reveals that this approach offers significant advantages in vibration mitigation compared to a linear system.

关键词： Offshore wind turbine Bi-directional PSTMD Nonlinear-memoryless-amplification behavior Nonlinear tensile force Integrated vibration control newton-raphson algorithm

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Finite deformation analysis of bi-modulus thermoelastic structures and its in of membranes

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COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING 2024年 427卷

作者： Ren, Xiaoqiang Du, Zongliang Chung, Hayoung Tang, Shan Guo, Yunhang Chen, Biaosong Guo, Xu Dalian Univ Technol Dept Engn Mech State Key Lab Struct Anal Optimizat & CAE Software Dalian 116023 Peoples R China Daian Univ Technol Ningbo Inst Ningbo 315016 Peoples R China Ulsan Natl Inst Sci & Technol Dept Mech Engn Ulsan 44919 South Korea

Tension-compression asymmetry, thermal -mechanical coupling, and finite deformation effects are common characters of many biological materials and engineering structures. By introducing different elastic constants under tension and compression, a thermo-mechanical bi-modulus constitutive model and a subsequent efficient computational analysis framework are proposed in the finite deformation regime. After we validate the convergence, accuracy, and robustness of the algorithm, we investigate the mechanical behavior of human brain tissue under varying intracranial pressure and temperature. Furthermore, with the use of the proposed bi-modulus thermoelasticity model, the classic tension -field theory is regularized, and wrinkling region and its evolution in membranes under thermomechanical loads can be effectively predicted, as an alternative to the computationally intensive post -buckling analyses.

关键词： Tension-compression asymmetry Thermal-mechanical coupling Finite deformation newton-raphson algorithm Wrinkling prediction

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A tight fit of the SIR dynamic epidemic model to daily cases of COVID-19 reported during the 2021-2022 Omicron surge in New York City: A novel approach

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STATISTICAL METHODS IN MEDICAL RESEARCH 2024年第10期33卷 1877-1898页

作者： Harris, Jeffrey E. MIT Dept Econ 50 Mem DrE52-300 Cambridge MA 02142 USA Eisner Hlth Adult Med Dept Los Angeles CA USA

We describe a novel approach for recovering the underlying parameters of the SIR dynamic epidemic model from observed data on case incidence. We formulate a discrete-time approximation of the original continuous-time model and search for the parameter vector that minimizes the standard least squares criterion function. We show that the gradient vector and matrix of second-order derivatives of the criterion function with respect to the parameters adhere to their own systems of difference equations and thus can be exactly calculated iteratively. Applying our new approach, we estimated a four-parameter SIR model from daily reported cases of COVID-19 during the SARS-CoV-2 Omicron/BA.1 surge of December 2021-March 2022 in New York City. The estimated SIR model showed a tight fit to the observed data, but less so when we excluded residual cases attributable to the Delta variant during the initial upswing of the wave in December. Our analyses of both the real-world COVID-19 data and simulated case incidence data revealed an important problem of weak parameter identification. While our methods permitted for the separate estimation of the infection transmission parameter and the infection persistence parameter, only a linear combination of these two key parameters could be estimated with precision. The SIR model appears to be an adequate reduced-form description of the Omicron surge, but it is not necessarily the correct structural model. Prior information above and beyond case incidence data may be required to sharply identify the parameters and thus distinguish between alternative epidemic models.

关键词： Susceptible-Infected-Removed model inversion problem newton-raphson algorithm nonlinear least squares COVID-19 SARS-CoV-2 Omicron variant parameter identification structural models reduced form models sloppy models underreporting heterogeneous mixing

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