Subjects -> PHYSICS (Total: 857 journals)
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PHYSICS (625 journals)                  1 2 3 4 | Last

Showing 1 - 200 of 741 Journals sorted alphabetically
Acta Acustica     Open Access   (Followers: 4)
Acta Mechanica     Hybrid Journal   (Followers: 22)
Acta Scientifica Naturalis     Open Access   (Followers: 2)
Advanced Composite Materials     Hybrid Journal   (Followers: 75)
Advanced Electronic Materials     Hybrid Journal   (Followers: 7)
Advanced Functional Materials     Hybrid Journal   (Followers: 71)
Advanced Materials     Hybrid Journal   (Followers: 254)
Advanced Quantum Technologies     Hybrid Journal   (Followers: 3)
Advanced Science Focus     Free   (Followers: 6)
Advanced Structural and Chemical Imaging     Open Access   (Followers: 2)
Advanced Theory and Simulations     Hybrid Journal   (Followers: 2)
Advances in Clinical Radiology     Full-text available via subscription   (Followers: 4)
Advances in Condensed Matter Physics     Open Access   (Followers: 5)
Advances in Geophysics     Full-text available via subscription   (Followers: 7)
Advances in High Energy Physics     Open Access   (Followers: 23)
Advances in Imaging and Electron Physics     Full-text available via subscription   (Followers: 4)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 33)
Advances in Natural Sciences : Nanoscience and Nanotechnology     Open Access   (Followers: 28)
Advances in OptoElectronics     Open Access   (Followers: 6)
Advances In Physics     Hybrid Journal   (Followers: 29)
Advances in Physics : X     Open Access   (Followers: 4)
Advances in Physics Theories and Applications     Open Access   (Followers: 12)
Advances in Remote Sensing     Open Access   (Followers: 59)
Aggregate     Open Access  
AIP Advances     Open Access   (Followers: 7)
AIP Conference Proceedings     Full-text available via subscription   (Followers: 2)
American Journal of Condensed Matter Physics     Open Access   (Followers: 7)
American Journal of Signal Processing     Open Access   (Followers: 14)
Anales (Asociación Física Argentina)     Open Access  
Analysis and Mathematical Physics     Hybrid Journal   (Followers: 9)
Annalen der Physik     Hybrid Journal   (Followers: 5)
Annales Geophysicae (ANGEO)     Open Access   (Followers: 21)
Annales Henri Poincaré     Hybrid Journal   (Followers: 2)
Annals of Nuclear Medicine     Hybrid Journal   (Followers: 6)
Annals of Physics     Hybrid Journal   (Followers: 7)
Annals of West University of Timisoara - Physics     Open Access   (Followers: 1)
Annual Reports on NMR Spectroscopy     Full-text available via subscription   (Followers: 4)
Annual Review of Analytical Chemistry     Full-text available via subscription   (Followers: 12)
Annual Review of Condensed Matter Physics     Full-text available via subscription   (Followers: 3)
Annual Review of Materials Research     Full-text available via subscription   (Followers: 8)
APL Materials     Open Access   (Followers: 12)
Applied Composite Materials     Hybrid Journal   (Followers: 54)
Applied Mathematics and Physics     Open Access   (Followers: 2)
Applied Physics A     Hybrid Journal   (Followers: 15)
Applied Physics Frontier     Open Access   (Followers: 2)
Applied Physics Letters     Hybrid Journal   (Followers: 44)
Applied Physics Research     Open Access   (Followers: 5)
Applied Physics Reviews     Hybrid Journal   (Followers: 11)
Applied Radiation and Isotopes     Hybrid Journal   (Followers: 4)
Applied Spectroscopy     Full-text available via subscription   (Followers: 24)
Applied Spectroscopy Reviews     Hybrid Journal   (Followers: 4)
Archive for Rational Mechanics and Analysis     Hybrid Journal   (Followers: 1)
Asia Pacific Physics Newsletter     Hybrid Journal   (Followers: 1)
Asian Journal of Physical and Chemical Sciences     Open Access   (Followers: 2)
ASTRA Proceedings     Open Access   (Followers: 3)
Astronomy & Geophysics     Hybrid Journal   (Followers: 49)
Astronomy and Astrophysics Review     Hybrid Journal   (Followers: 39)
Atoms     Open Access   (Followers: 1)
Attention, Perception & Psychophysics     Full-text available via subscription   (Followers: 15)
Axioms     Open Access   (Followers: 1)
Bangladesh Journal of Medical Physics     Open Access  
Bauphysik     Hybrid Journal   (Followers: 1)
Biomaterials     Hybrid Journal   (Followers: 55)
Biomedical Imaging and Intervention Journal     Open Access   (Followers: 5)
Biophysical Reviews     Hybrid Journal   (Followers: 2)
Biophysical Reviews and Letters     Hybrid Journal   (Followers: 5)
BJR|Open     Open Access  
Boson Journal of Modern Physics     Open Access   (Followers: 9)
Brazilian Journal of Physics     Hybrid Journal  
Bulletin of Materials Science     Open Access   (Followers: 43)
Bulletin of Taras Shevchenko National University of Kyiv. Series: Physics and Mathematics     Open Access  
Bulletin of the Atomic Scientists     Hybrid Journal   (Followers: 7)
Bulletin of the Lebedev Physics Institute     Hybrid Journal  
Bulletin of the Russian Academy of Sciences: Physics     Hybrid Journal   (Followers: 1)
Caderno Brasileiro de Ensino de Física     Open Access  
Canadian Journal of Physics     Hybrid Journal   (Followers: 11)
Cell Reports Physical Science     Open Access  
Cells     Open Access   (Followers: 2)
CERN courier. International journal of high energy physics     Free   (Followers: 8)
Chemical Physics Impact     Full-text available via subscription  
ChemPhysMater     Full-text available via subscription  
Chinese Journal of Chemical Physics     Hybrid Journal   (Followers: 1)
Chinese Journal of Physics     Hybrid Journal   (Followers: 1)
Ciencia     Open Access  
Clinical Spectroscopy     Open Access  
Cogent Physics     Open Access  
Colloid Journal     Hybrid Journal   (Followers: 2)
Communications in Mathematical Physics     Hybrid Journal   (Followers: 2)
Communications in Numerical Methods in Engineering     Hybrid Journal   (Followers: 2)
Communications Materials     Open Access  
Communications Physics     Open Access  
Complex Analysis and its Synergies     Open Access   (Followers: 2)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 173)
Composites Part B : Engineering     Hybrid Journal   (Followers: 219)
Composites Part C : Open Access     Open Access   (Followers: 2)
Computational Astrophysics and Cosmology     Open Access   (Followers: 6)
Computational Condensed Matter     Open Access   (Followers: 1)
Computational Materials Science     Hybrid Journal   (Followers: 25)
Computational Mathematics and Mathematical Physics     Hybrid Journal   (Followers: 5)
Computational Particle Mechanics     Hybrid Journal   (Followers: 1)
Computer Physics Communications     Hybrid Journal   (Followers: 9)
Condensed Matter     Open Access   (Followers: 2)
Contemporary Physics     Hybrid Journal   (Followers: 26)
Continuum Mechanics and Thermodynamics     Hybrid Journal   (Followers: 8)
Contributions to Plasma Physics     Hybrid Journal   (Followers: 3)
Cryogenics     Hybrid Journal   (Followers: 60)
Current Applied Physics     Full-text available via subscription   (Followers: 4)
Current Science     Open Access   (Followers: 115)
Diagnostic and Interventional Imaging     Full-text available via subscription  
Diamond and Related Materials     Hybrid Journal   (Followers: 10)
Discrete and Continuous Models and Applied Computational Science     Open Access  
Doklady Physics     Hybrid Journal   (Followers: 1)
e-Boletim da Física     Open Access  
East European Journal of Physics     Open Access   (Followers: 1)
Edufisika : Jurnal Pendidikan Fisika     Open Access  
EDUSAINS     Open Access  
Egyptian Journal of Remote Sensing and Space Science     Open Access   (Followers: 25)
EJNMMI Physics     Open Access  
Emergent Scientist     Open Access  
Engineering Failure Analysis     Hybrid Journal   (Followers: 68)
Engineering Fracture Mechanics     Hybrid Journal   (Followers: 24)
Environmental Fluid Mechanics     Hybrid Journal   (Followers: 11)
EPJ Quantum Technology     Open Access   (Followers: 2)
EPJ Techniques and Instrumentation     Open Access  
EPJ Web of Conferences     Open Access   (Followers: 1)
EUREKA : Physics and Engineering     Open Access  
European Physical Journal - Applied Physics     Full-text available via subscription   (Followers: 19)
European Physical Journal C     Hybrid Journal   (Followers: 2)
Europhysics News     Open Access  
Experimental and Computational Multiphase Flow     Hybrid Journal  
Experimental Mechanics     Hybrid Journal   (Followers: 21)
Experimental Techniques     Hybrid Journal   (Followers: 51)
Exploration Geophysics     Hybrid Journal   (Followers: 4)
Few-Body Systems     Hybrid Journal   (Followers: 1)
Fire and Materials     Hybrid Journal   (Followers: 5)
FirePhysChem     Open Access  
Flexible Services and Manufacturing Journal     Hybrid Journal   (Followers: 2)
Fluctuation and Noise Letters     Hybrid Journal  
Fluid Dynamics     Hybrid Journal   (Followers: 27)
Fortschritte der Physik/Progress of Physics     Hybrid Journal  
Frontiers in Nanotechnology     Open Access   (Followers: 1)
Frontiers in Physics     Open Access   (Followers: 6)
Frontiers of Materials Science     Hybrid Journal   (Followers: 5)
Frontiers of Physics     Hybrid Journal   (Followers: 2)
Fusion Engineering and Design     Hybrid Journal   (Followers: 6)
Geochemistry, Geophysics, Geosystems     Full-text available via subscription   (Followers: 35)
Geografiska Annaler, Series A : Physical Geography     Hybrid Journal   (Followers: 4)
Geophysical Research Letters     Full-text available via subscription   (Followers: 161)
Giant     Open Access  
Glass Physics and Chemistry     Hybrid Journal   (Followers: 1)
Granular Matter     Hybrid Journal  
Graphs and Combinatorics     Hybrid Journal   (Followers: 4)
Gravitation and Cosmology     Hybrid Journal   (Followers: 6)
Heat Transfer - Asian Research     Hybrid Journal   (Followers: 10)
High Energy Density Physics     Hybrid Journal   (Followers: 3)
High Pressure Research: An International Journal     Hybrid Journal   (Followers: 3)
Himalayan Physics     Open Access  
IEEE Embedded Systems Letters     Hybrid Journal   (Followers: 60)
IEEE Journal of Quantum Electronics     Hybrid Journal   (Followers: 19)
IEEE Journal on Multiscale and Multiphysics Computational Techniques     Hybrid Journal  
IEEE Magnetics Letters     Hybrid Journal   (Followers: 7)
IEEE Nanotechnology Magazine     Hybrid Journal   (Followers: 45)
IEEE Reviews in Biomedical Engineering     Hybrid Journal   (Followers: 19)
IEEE Signal Processing Magazine     Full-text available via subscription   (Followers: 98)
IEEE Solid-State Circuits Magazine     Hybrid Journal   (Followers: 11)
IEEE Transactions on Autonomous Mental Development     Hybrid Journal   (Followers: 8)
IEEE Transactions on Biomedical Engineering     Hybrid Journal   (Followers: 35)
IEEE Transactions on Broadcasting     Hybrid Journal   (Followers: 11)
IEEE Transactions on Geoscience and Remote Sensing     Hybrid Journal   (Followers: 174)
IEEE Transactions on Haptics     Hybrid Journal   (Followers: 4)
IEEE Transactions on Industrial Electronics     Hybrid Journal   (Followers: 85)
IEEE Transactions on Industry Applications     Hybrid Journal   (Followers: 57)
IEEE Transactions on Learning Technologies     Full-text available via subscription   (Followers: 12)
IEEE Transactions on Quantum Engineering     Open Access   (Followers: 3)
IEEE Transactions on Services Computing     Hybrid Journal   (Followers: 5)
IEEE Transactions on Software Engineering     Hybrid Journal   (Followers: 84)
IEEE Women in Engineering Magazine     Hybrid Journal   (Followers: 11)
IEEE/OSA Journal of Optical Communications and Networking     Hybrid Journal   (Followers: 19)
IET Optoelectronics     Open Access   (Followers: 2)
Il Colle di Galileo     Open Access  
Image Analysis & Stereology     Open Access   (Followers: 1)
Imaging Science Journal     Hybrid Journal   (Followers: 3)
ImmunoInformatics     Open Access   (Followers: 1)
Indian Journal of Biochemistry and Biophysics (IJBB)     Open Access   (Followers: 3)
Indian Journal of Physics     Hybrid Journal   (Followers: 18)
Indian Journal of Pure & Applied Physics (IJPAP)     Open Access   (Followers: 36)
Indian Journal of Radio & Space Physics (IJRSP)     Open Access   (Followers: 49)
Infinite Dimensional Analysis, Quantum Probability and Related Topics     Hybrid Journal   (Followers: 1)
InfraMatics     Open Access  
Infrared Physics & Technology     Hybrid Journal   (Followers: 11)
Intelligent Transportation Systems Magazine, IEEE     Full-text available via subscription   (Followers: 12)
Intermetallics     Hybrid Journal   (Followers: 21)
International Applied Mechanics     Hybrid Journal   (Followers: 5)
International Heat Treatment and Surface Engineering     Hybrid Journal   (Followers: 5)
International Journal for Computational Methods in Engineering Science and Mechanics     Hybrid Journal   (Followers: 13)
International Journal for Ion Mobility Spectrometry     Hybrid Journal   (Followers: 1)
International Journal for Simulation and Multidisciplinary Design Optimization     Open Access   (Followers: 5)
International Journal of Abrasive Technology     Hybrid Journal   (Followers: 2)
International Journal of Aeroacoustics     Hybrid Journal   (Followers: 37)
International Journal of Applied Electronics in Physics & Robotics     Open Access   (Followers: 3)

        1 2 3 4 | Last

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Journal Cover
IEEE Transactions on Industrial Electronics
Journal Prestige (SJR): 2.192
Citation Impact (citeScore): 9
Number of Followers: 85  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0278-0046
Published by IEEE Homepage  [228 journals]
  • IEEE Industrial Electronics Society

    • Free pre-print version: Loading...

      Abstract: Presents a listing of the editorial board, board of governors, current staff, committee members, and/or society editors for this issue of the publication.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • IEEE Industrial Electronics Society

    • Free pre-print version: Loading...

      Abstract: Presents a listing of the editorial board, board of governors, current staff, committee members, and/or society editors for this issue of the publication.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Information for Authors

    • Free pre-print version: Loading...

      Abstract: These instructions give guidelines for preparing papers for this publication. Presents information for authors publishing in this journal.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • A Three-Level Output Modulation Strategy for Conventional 3 × N Direct
           Matrix Converters

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      Authors: Hui Wang;Xida Chen;Mei Su;Guanguan Zhang;Frede Blaabjerg;Wenjing Xiong;
      Pages: 9689 - 9699
      Abstract: To utilize the full potential of the direct matrix converter (DMC) and improve the output waveform quality, a three-level output strategy for conventional 3 × N (N≥3) DMCs is presented, where three-level output voltages are achieved without any changes in the topology. In this developed strategy, the DMC is treated as a two-stage converter that consists of a fictitious rectifier and a neutral-point clamped (NPC) three-level inverter. By applying a phase-shifted carrier modulation strategy to the rectifier and a modified carrier-based double-signal pulsewidth modulation strategy to the NPC inverter, sinusoidal input and output, reduced switching losses, and controllable input power factors are achieved in conventional 3 × N DMCs. The developed three-level output strategy improves output waveform quality while sacrificing input performance to some extent. Finally, the effectiveness of the developed strategy is verified by both simulations and experimental results.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Distributed Direct Power Sliding-Mode Control for Islanded AC Microgrids

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      Authors: Carlos Alfaro;Ramon Guzman;Luis Garcia de Vicuña;Hasan Komurcugil;Helena Martín;
      Pages: 9700 - 9710
      Abstract: The aim of this article is to develop a novel distributed direct power sliding-mode control for an islanded AC microgrid. This solution replaces the droop mechanism of each inverter with two separate sliding surfaces working as primary/secondary controllers. The design of these surfaces is based on the dynamic model of the active and reactive powers to enhance the robustness against line impedance mismatches. Moreover, a theoretical stability analysis is presented. The main features of this proposed control are to regulate the voltage and frequency achieving an accurate active and reactive power sharing, achieve stability under a wide range of line impedances, and provide robustness toward external disturbances, including communication failures. Finally, the experimental results verify the controller performance, the stability with different line impedances, and the robustness against communication partitions.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • A Simple Hardware-Based Fault-Tolerant Method for Cascaded H-Bridge
           Converters

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      Authors: Ehsan Moradi;Hossein Iman-Eini;Samad Sheikhaei;
      Pages: 9711 - 9720
      Abstract: A new fault-tolerant strategy for cascaded H-bridge (CHB) multilevel converters under single-fault conditions is proposed in this study. This approach is not dependent on the type and location of the fault. It uses an auxiliary H-bridge cell to fix the fault and to restore the prefault operating condition. The auxiliary H-bridge cell uses a dc-link capacitor instead of the dc power source to simplify the cell structure and minimize the necessary components. In addition, the capacitance value into the auxiliary cell is calculated using mathematical equations. The auxiliary cell is inserted to the converter after fault detection and bypassing the faulty switch. Furthermore, due to the flexibility of space vector modulation, it is utilized to regulate the capacitor voltage in the fault condition. Finally, simulation and experimental results are presented for a three-phase seven-level system to validate the claims and confirm new method effectiveness.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Maximum Torque Per Ampere Algorithm for Five-Phase Synchronous Reluctance
           Machines

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      Authors: Andrea Cervone;Obrad Dordevic;
      Pages: 9721 - 9730
      Abstract: This article presents a maximum torque per ampere strategy for a five-phase synchronous reluctance drive. The approach is developed considering general machine parameters and is formalized as a constrained optimization problem. The optimal solution is found analytically by using Lagrange’s multipliers method and is based on the computation of the eigenvalues and eigenvectors of the inductance derivatives matrix. The proposed approach is evaluated both numerically and experimentally. It is also compared with other current references control strategies, effectively showing a reduction of the machine rms currents for the same developed torque. The same approach can also be extended to machines with a different number of phases.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Precise Mathematical Model of PSCM Class-D Amplifiers

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      Authors: Hossein Pakniat;
      Pages: 9731 - 9738
      Abstract: A mathematical analysis of four-level (three-phase) phase-shifted carrier modulation class-D amplifiers with analog feedback is proposed. The nonlinear difference equations are extracted and solved using the perturbation theorem. In this way, a closed-form function describes the low-frequency part of the output for an arbitrary input signal. The results are generalized for an arbitrary number of levels by analogy, well matched with the previous model of two-, three-, and the proposed four-level ones. The analytical results confirm that, apart from switching frequency, the multilevel class-D amplifiers converge to linear amplifiers as the number of output levels increases. An analytical equation expresses the harmonic distortion of practically interesting five-level amplifiers with bridge-tied load. The model is verified by system-level simulations and circuit-level implementation. In this way, a prototype fully differential five-level circuit is implemented on the printed circuit board to confirm the model.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Model-Free Hybrid Parallel Predictive Speed Control Based On Ultralocal
           Model of PMSM for Electric Vehicles

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      Authors: Siyu Gao;Yanjun Wei;Di Zhang;Hanhong Qi;Yao Wei;Zeyu Yang;
      Pages: 9739 - 9748
      Abstract: Conventional model predictive direct speed control (MP-DSC) has received extensive attention because of its easy implementation, fast dynamic response, and simple structure. However, weighting factor and parameter mismatch are two key factors restricting the control performance of MP-DSC. In this article, a model-free hybrid parallel predictive speed control (MF-HPPSC) based on ultralocal model is proposed to solve the above-mentioned problems. First, the multiobjective parallel predictive speed control method realizes synchronous control of speed, torque, and flux linkage without weighting factor. The original excellent dynamic response capability is guaranteed, and the steady-state performance is simultaneously enhanced. Moreover, the linear extended state observer (LESO) designed by the unique ultralocal model makes the calculation process of future state prediction without any machine parameters, and the robustness of the system is significantly improved. Finally, the simulation and experiment comparison among the conventional MP-DSC, conventional model-free control, and the proposed MF-HPPSC verified the superiority of the proposed method.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Online Detection and Location of Eccentricity Fault in PMSG With External
           Magnetic Sensing

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      Authors: Qi Xu;Shuai Yuan;Xuyang Liu;Philip W. T. Pong;Chunhua Liu;
      Pages: 9749 - 9760
      Abstract: The detection and location of eccentricity faults in a permanent magnet synchronous generator (PMSG) become increasingly essential, especially in safety-critical applications. However, the existing approaches for monitoring eccentricity subject to many limitations. In this article, a novel method for online detection and location of the eccentricity fault in a PMSG is proposed based on the external magnetic sensing. The noninvasiveness facilitates installation and maintenance work. In this article, the effect of different eccentricity faults on the external leakage flux density is analyzed theoretically with the magnetic equivalent circuit method first. Then, two indicators are proposed for detecting static eccentricity (SE) and dynamic eccentricity (DE), respectively. The amplitudes of the SE and DE indicators are proportional to the fault degree. The angle of the SE indicator proves to be the direction of SE. Meanwhile, two indicators show excellent robustness and are independent of loads and rotation speed. Moreover, these indicators can be applied in any surface-mounted PMSG with a three-multiple number of slots. Accordingly, an algorithm to diagnose the eccentricity fault is shown based on two indicators from three sensing points outside. The computation of the method is light, which leads to fast detection speed. Finally, the accurate results in multioperating conditions from simulations and experiments verify the feasibility of the proposed approach.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Analytical Methodology for Eddy Current Loss Simulation in Armature
           Windings of Synchronous Electrical Machines With Permanent Magnets

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      Authors: Dmitry Golovanov;Alessandro Galassini;Tommaso Transi;Chris Gerada;
      Pages: 9761 - 9770
      Abstract: This article describes a novel analytical methodology for eddy current losses simulation in the windings of permanent magnet synchronous machines. The methodology is based on subdomain modeling technique in conjunction with solving of ordinary differential equations system. The main advantage of the proposed method is high accuracy and significant reduction of simulation time in comparison with finite-element modeling (FEM) technique that is frequently used for eddy current loss modeling. The proposed model allows fast and accurate evaluation of proximity and skin effect in conductors in time domain for an arbitrary current waveform and machine duty cycle. The main difference from previously presented analytical methods is the possibility to evaluate losses for a wider range of conductors geometries, regardless their shape, dimensions, location in the stator slots, and rotor speed. The main contribution and novelty of the proposed analytical approach is simultaneous implementation of subdomain modeling technique and strands segmentation concept followed by the eddy current effect representation through the equivalent circuit. This approach allows reducing the computational time while keeping the accuracy close to the FEM result. The proposed model was compared to FEM, using different types and sizes of conductors and also validated experimentally.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Robust Predictive Control for Linear Permanent Magnet Synchronous Motor
           Drives Based on an Augmented Internal Model Disturbance Observer

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      Authors: Cong Bai;Zhonggang Yin;Yanqing Zhang;Jing Liu;
      Pages: 9771 - 9782
      Abstract: To optimize the current-control performance of the linear permanent magnet synchronous motor (LPMSM) drive system, a robust continuous time model-based predictive control for the LPMSM drive systems is proposed in this article. Since the current regulation technology is fundamental for obtaining the precise thrust of the LPMSM, a continuous time model-based predictive control is utilized in the current loop to achieve a fast dynamic response and accurate tracking accuracy. However, the predictive control is a model-based scheme, thus, the model uncertainties and parameter variations will influence the accuracy of stator current. To solve this problem, an augmented internal model disturbance observer is proposed to estimate the lumped disturbances and then compensate to the forward channel. First, the internal model equation of the current loop is constructed by the internal model control principle. Then, a new augmented matrix is constructed by introducing the error variables of the actual current and the internal model current. The observer control law is designed by the state feedback theory, and the observer parameters are optimized by pole assignment method. Finally, the experimental results demonstrate the correctness and effectiveness of the proposed method.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Evaluation of Operating Range of a Machine Emulator for a Back-to-Back
           Power-Hardware-in-the-Loop Test Bench

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      Authors: Nimananda Sharma;Georgios Mademlis;Yujing Liu;Junfei Tang;
      Pages: 9783 - 9792
      Abstract: Inverter testing using laboratory test benches with rotating machines can be bulky, complex, and maintenance intensive. One solution is to use machine emulator for laboratory testing of inverters. The emulator is controlled in such a way that currents and voltages at the terminals resemble a machine connected to a mechanical load. A machine emulator for a back-to-back power-hardware-in-the-loop (PHIL) test bench is proposed in this article. The PHIL test bench consists of two identical voltage source converters (VSCs) with three single-phase inductors as coupling network. The two VSCs are connected to the same direct current supply. One VSC acts as inverter under test (IUT), while the other is part of machine emulator. Aim of this article is to analyze the influence of coupling inductance on operating range of the emulator. An analytical method to dimension the coupling inductance is introduced and verified in experiments. The operating range of the emulator is also evaluated. The performance of the IUT when tested with an equivalent permanent magnet synchronous motor in simulations and that of a prototyped 60-kW rated machine emulator are compared. Sensitivity of emulator control on parameter estimation is discussed. The experimental results show good agreement with simulations in both steady-state and dynamic conditions.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • A Harmonic Injection Method Equivalent to the Resonant Controller for
           Speed Ripple Reduction of PMSM

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      Authors: Xiaosheng Wang;Chaoqiang Jiang;Feifei Zhuang;Christopher H. T. Lee;C. C. Chan;
      Pages: 9793 - 9803
      Abstract: This article proposes a straightforward and effective control strategy to reduce the periodic speed ripple of the permanent-magnet synchronous motor. The control strategy can be described as injecting current harmonics whose amplitude and phase can be adjusted automatically to compensate for periodic speed ripple. Compared with the resonant controller with the Tustin transform, the method proposed in the article can track speed ripple frequency without frequency displacement, realizing no steady-state error. Besides, the system stability is analyzed, and the phase compensation scheme is proposed to increase the phase stability. Moreover, the equivalence between the harmonic injection module and the resonant controller has been analyzed, which provides a simple way to understand the phase compensation of the resonant controller. The theoretical analysis and experimental results are presented to verify the feasibility of the proposed harmonic injection method.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Nonlinear Semianalytical Model for Axial Flux Permanent-Magnet Machine

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      Authors: Baocheng Guo;Yunlu Du;Zakarya Djelloul-Khedda;Fei Peng;Jianning Dong;Yunkai Huang;Frédéric Dubas;Kamel Boughrara;
      Pages: 9804 - 9816
      Abstract: In this article, we propose a novel nonlinear semianalytical model (AM) for the magnetic field calculation of electric machines. The nonlinear properties and local saturation effect of the iron part are taken into consideration in Cartesian coordinates, which is the main contribution of the proposed model. Thus, high accuracy of electromagnetic field results can be obtained with the low computational time cost. The model is developed based on the harmonic modeling technique by solving Maxwell's equations. The detailed theoretical derivations, which use the complex Fourier series and the Cauchy product, are presented. To verify the proposed model, an axial flux permanent-magnet (PM) machine is selected to be investigated. Both finite-element model and experimental results agree well with that of the proposed model. Moreover, the nonlinear AM has potential application for other types of PM electrical motor in Cartesian coordinates, such as flat PM linear machines.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Multiple Current Harmonics Suppression for Low-Inductance PMSM Drives With
           Deadbeat Predictive Current Control

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      Authors: Shangjian Dai;Jiabin Wang;Zhigang Sun;Ellis Chong;
      Pages: 9817 - 9826
      Abstract: Inverter nonlinearity and nonsinusoidal back electromagnetic forces (EMFs) can cause large current harmonics in permanent magnet synchronous machine (PMSM) drives, especially for those with low inductance, resulting in increased torque ripples and losses. With deadbeat predictive current control (DBPCC), the feature of high control bandwidth can reduce, to some extent, the unwanted low-order current harmonics but not remarkably. Therefore, this article presents a novel method, named adaptive harmonic reference correcting current injection, to compensate the effects of inverter nonlinearity and back EMF harmonics for DBPCC of PMSM drives. It can effectively eliminate all the resultant current harmonics caused by nonideal factors and maintain the high dynamic responses of DBPCC, even under the conditions where the sampling-to-harmonic frequency ratios are quite low. Furthermore, the proposed method requires no information about both the machine and inverter. It can be easily implemented and is parameter insensitive. Extensive simulation and experimental results of a prototype low-inductance PMSM drive have been presented to verify the proposed method.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Current Sensor Fault-Tolerant Control for Five-Phase PMSM Drives Based on
           Third-Harmonic Space

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      Authors: Jianhua Li;Bochao Du;Tianxu Zhao;Shaopeng Wu;Shumei Cui;
      Pages: 9827 - 9837
      Abstract: According to the different forms of back electromotive force, five-phase permanent-magnet synchronous motors (FPMSMs) can be divided into two types: sinusoidal FPMSMs (SFPMSMs) and trapezoidal FPMSMs (TFPMSMs). In field-oriented-controlled FPMSM drives, current sensors may malfunction in harsh working environments. In this article, two current sensor fault-tolerant control (FTC) strategies based on third-harmonic space, respectively, corresponding to SFPMSMs and TFPMSMs are proposed. Different from three-phase motor, the decoupled model of five-phase motor contains two orthogonal subspaces. The key to both strategies is that the third-harmonic space currents are controlled at zero when current sensors malfunction. Thus, the faulty phase current can be estimated with other phase currents by using the constraint equations of current transformation. For SFPMSMs, vector control and sinusoidal pulsewidth modulation technology are used to control the third-harmonic space currents to zero. For TFPMSMs, offset axis transformation and resonant observer are adopted for third-harmonic space current estimation and the third-harmonic space currents are controlled to zero by using the estimated values as feedback of vector control. The experimental results demonstrate that the robustness of both current sensor FTC systems is well performed in the whole speed range.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Instantaneous Torque Modeling and Torque Ripple Reduction Strategy for
           Flux Modulated Doubly-Salient Reluctance Motor Drives

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      Authors: Zhiyue Yu;Chun Gan;Kai Ni;Yu Chen;Ronghai Qu;
      Pages: 9838 - 9848
      Abstract: In this article, a novel instantaneous electromagnetic torque modeling technique and current component distribution strategy are proposed for torque ripple reduction in three-phase flux modulated doubly-salient reluctance motor (FMDRM) drives. First, the analytical model of the instantaneous electromagnetic torque of a three-phase FMDRM is established, where the contributions of current components and harmonic inductance components are considered. The generation mechanisms of the average torque and torque ripple components are investigated in detail. Furthermore, based on the analytical instantaneous electromagnetic torque model, a simplified current component distribution strategy is proposed to further reduce the torque ripple of the FMDRM. Taking the torque ripple minimization as the optimization objective, the current advanced angle is optimized and the corresponding current component distribution strategy is carried out to reduce the torque ripple. The magnetic circuit saturation effect is also taken into account. Compared to the conventional scheme, the control freedom degree of the three-dimensional current controller in the FMDRM drive is fully utilized and the torque ripple of the FMDRM can be significantly reduced without the sacrifice of output torque capability and system efficiency. Experimental results are carried out on a three-phase 12/8 FMDRM prototype to verify the effectiveness of the proposed control strategy.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • DC-Link Voltage Constraint Strategy for DC Power Supply Film-Capacitor
           Drive System Based on Improved Model Predictive Control

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      Authors: Zhenrui Zhang;Haohao Guo;Yancheng Liu;
      Pages: 9849 - 9859
      Abstract: DC-link voltage oscillation is a common problem that needs special attention in dc power supply film-capacitor drive systems. For this problem, an improved model predictive control method is presented in this article, which achieves system stability control by adding voltage stability constraint of dc-link in the cost function. First, the discrete predictive equations of motor current and LC filter voltage for permanent magnet synchronous motor are derived in this article. The system stability is proved by analyzing the system damping with voltage constraint in the meantime. The weight factor of the cost function based on exponential function is designed to accelerate the suppression of dc-link voltage oscillation in the dynamic process. Second, a full-order observer is designed for observing the LC filter inductor current, which is designed to reduce hardware costs. Third, an improved control set method is proposed to improve the steady-state performance of each control item in the cost function. Finally, a hardware platform based on DSP is built to verify the validity of the stability constraint scheme proposed in this article.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Online Adaptation of Two-Parameter Inverter Model in Sensorless Motor
           Drives

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      Authors: Jiahao Chen;Jie Mei;Xin Yuan;Yuefei Zuo;Jingwei Zhu;Christopher H. T. Lee;
      Pages: 9860 - 9871
      Abstract: This article designs parameter adaptation algorithms for online simultaneous identification of a two-parameter sigmoid inverter model for compensating inverter nonlinearity to reduce the voltage error in flux estimation for a position sensorless motor drive. The inverter model has two parameters, $a_2$ and $a_3$, where $a_2$ is “plateau voltage” and $a_3$ is a shape parameter that mainly accounts for the stray capacitor effect. Parameter $a_3$ is identified by the $(6kpm 1)$th order harmonics in measured current. Parameter $a_2$ is identified by the amplitude mismatch of the estimated active flux. It is found that the classic linear flux estimator, i.e., the hybrid of voltage model and current model, cannot be used for $a_2$ identification. This article proposes to use a saturation function based nonlinear flux estimator to build an effective indicator for $a_2$ error. The coupled identifiability of the two parameters is revealed and analyzed, which was not seen in literature. The concept of the low current region where the two-way coupling between $a_2$ and $a_3$ occurs is established. In theory, it is suggested to stop the inverter identification in the low c-rrent region. However, the experimental results in which dc bus voltage variation and load change are imposed have shown the effectiveness of the proposed online inverter identification and compensation method, even in low current region.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • High-Fidelity Induction Motor Simulation Model Based on Finite Element
           Analysis

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      Authors: Joon-Hee Lee;Yong-Cheol Kwon;Seung-Ki Sul;
      Pages: 9872 - 9883
      Abstract: This article proposes a new high-fidelity simulation model of an induction motor (IM) based on finite-element analysis (FEA). The proposed model enables fast and accurate IM simulation with the inverter circuit model and control algorithm. That is, the proposed model can represent non-ideal features of IM, such as magnetic saturation, spatial harmonics, skew, and saturation-induced saliency in high accuracy. To construct the proposed model, a dq equivalent circuit of the squirrel cage rotor is introduced. Based on this, the static FEA is conducted which can accelerate the model construction compared to the conventional time-stepping FEA technique. Then, a flux-based IM model is established, which has advantages on speed, accuracy, and memory size in the simulation. To verify the effectiveness of the proposed model, the models are constructed for two commercial IMs used for the industrial drive. IM control algorithms are tested in various operating conditions on the proposed model. The results are compared with the time-stepping FEA and the experiment for the verification of the proposed model.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Mechanism of Torque Ripple Generation by Time and Space Harmonic Magnetic
           Fields in Permanent Magnet Synchronous Motors

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      Authors: Katsumi Yamazaki;Kento Utsunomiya;Hiroaki Ohiwa;
      Pages: 9884 - 9894
      Abstract: The mechanism of torque ripple generation by time and space harmonic magnetic fields in permanent magnet synchronous motors is investigated to obtain advanced motor designs. The general expression between the torque ripples and harmonic air-gap flux densities in the motor is derived by using Maxwell stress tensor. Both the numerical and experimental verifications of this expression are carried out. By using this expression, the difference of the torque ripple generation between the surface and interior permanent magnet synchronous motors are discussed. Based on these investigations, the shape of the rotor surface of an interior permanent magnet motor is optimized. It is clarified that specific harmonic components of thetorque ripples in interior permanent magnet synchronous motors can be reduced to be nearly zero by optimizing the rotor surface shape.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Ultrafast, Redundant, and Unpolarized DC Energy Extraction Systems for the
           Protection of Superconducting Magnet Circuits

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      Authors: Piotr Borkowski;Marek Bartosik;Michał Rodak;Adrian Sienicki;Franciszek Wójcik;Bozhidar Panev;Félix Rodriguez-Mateos;Andrzej Siemko;
      Pages: 9895 - 9904
      Abstract: The article presents a new family of low voltage dc switching energy extraction (EES) systems designed for protection of superconducting magnet circuits at CERN, which is appropriate also in other applications. During normal operation, superconducting magnet circuits can store large amounts of energy in their magnetic fields. In the case of a resistive transition (known as “quench”), this energy may be dangerous as it can lead to high temperatures and voltages, eventually damaging the superconducting magnet coils. To prevent this, the magnetic energy must be extracted and dissipated outside the superconducting windings. For this purpose, dedicated energy absorbers are introduced in the circuit by means of opening of dc switches. For the protection of future superconducting magnet circuits at CERN, direct current switching systems (DCSS) with rated currents of 2000 and 600 A have been developed and qualified. Each DCSS is unpolarized and redundant, i.e., composed of two identical direct current switch (DCS) connected in series. Two methods for the current commutation toward the energy absorber element have been investigated, the first one based on IGBT and the second one based on thyristors. A high-power, inductive-dynamic drive provides the ultrafast opening of the vacuum interrupter in the DCS.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • The Digital–Analog Hybrid Cable Voltage-Drop Compensation Control
           Strategy Based on a Novel Impedance Detection Method

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      Authors: Mingzhu Fang;Donglai Zhang;Xianbin Qi;Wei Gao;
      Pages: 9905 - 9915
      Abstract: A voltage drop normally occurs when a power source runs for a load system through long-distance cables. To compensate for such voltage drops, it is necessary to provide remote detecting and controlling of the load-side voltage and boost to the required voltage. In this article, a novel impedance detection method providing more reliable and accurate resistance and inductance measured results for remote cables is presented. Meanwhile, a digital–analog hybrid control strategy based on the impedance detection method is presented to compensate for the voltage drop and delayed response caused by cable intrinsic impedance. Compared with traditional methods, the proposed strategy performs detection and compensation at the source of the cable, and can be integrated into power source devices without imposing extra burden to the load system, which is more attractive and promising in engineering application. Finally, a prototype is built for experimental verification, and a systematic and intuitive comparison is conducted with existing voltage-drop compensation methods. The experimental and comparative results indicate that the problems of voltage drop and delayed response caused by long-distance cables are solved, and the accurate and rapid regulation of the remote voltage is achieved.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Fault-Tolerant Operation Strategy for Reliability Improvement of a
           Switched-Capacitor Multilevel Inverter

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      Authors: Mohammadjavad Hassani;Erfan Azimi;Aryorad Khodaparast;Jafar Adabi;Edris Pouresmaeil;
      Pages: 9916 - 9926
      Abstract: The necessity of using several components in multilevel inverters jeopardizes the reliability of their operation. Hence, the aim of this article is to propose a novel single-phase fault-tolerant topology based on a switched-capacitor concept to ensure the robustness of the converter in the occurrence of a fault. The proposed single-source converter steps up the input voltage seven times with a simple control strategy. Fault tolerance of the converter is achieved by considering multiple fault cases and providing several redundant switching schemes concerning the type and location of failure. Each switching scheme is designed in a way to ensure the tolerability to both single and multiple open-/short-circuit failures. Also, self-voltage balancing of the capacitors, as well as the same amount of voltage levels and amplitude in the output, is guaranteed. Experimental analysis is carried out, and the results confirm the viability of the proposed inverter under normal and postfault operating modes.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Output Power Regulation of a Series-Series Inductive Power Transfer System
           Based on Hybrid Voltage and Frequency Tuning Method for Electric Vehicle
           Charging

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      Authors: Amr Mostafa;Yao Wang;Hua Zhang;Chong Zhu;Ying Mei;Ningfei Jiao;Fei Lu;
      Pages: 9927 - 9937
      Abstract: In the inductive charging scenario of an electric vehicle (EV), the charger should have the capability to flexibly regulate the output power regardless of the misalignment and EV battery voltage. This article proposes a hybrid voltage and frequency tuning strategy for a series-series (SS) inductive power transfer (IPT) system to regulate power through 0 to 3.3 kW at any battery voltages and misalignment conditions without using additional converters. A voltage tuning is used to achieve full-power of 3.3 kW and partly contribute to reducing the power. When the input voltage achieves the lower limit, a frequency tuning is used to further decrease the power to 0 W, achieving the regulation through 0 to full power. The practical charging region is specified by 110 mm airgap, 100 mm misalignment in both x and y directions, and 180–240 V battery voltage range. Experiments are carried out at various conditions, and it shows that with an input voltage range of 180–380 V and a frequency of 82.5–87.9 kHz, the charging power can be regulated between 100 W and 3.3 kW at any case in the specified working region. In addition, a peak dc-dc efficiency of 95.7% is achieved at 3.29 kW.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • New Combined OBC and LDC System for Electric Vehicles With 800 V Battery

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      Authors: Dae-Woo Lee;Bom-Seok Lee;Jae-Hyun Ahn;Ji-Yeon Kim;Jae-Kuk Kim;
      Pages: 9938 - 9951
      Abstract: This article proposes a new vehicle charging system (VCS) that combines an on-board charger (OBC) and a low-voltage dc–dc converter (LDC) for electric vehicles with an 800 V battery system. The proposed VCS improves the power density by integrating the LDC and OBC transformers and the LDC primary and OBC secondary components. Moreover, a new method is proposed for reducing the voltage to limit the high voltage generated in the link capacitor due to the multiwinding transformer. Furthermore, the proposed converter can simultaneously charge an auxiliary battery and a main battery. To confirm the validity of the proposed converter, a prototype rated with 3.3 kW OBC and 1.8 kW LDC is analyzed and the operating characteristics are described.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Optimal Switching-Sequence-Based Model Predictive Control for a Hybrid
           Multilevel STATCOM

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      Authors: Kourosh Khalaj Monfared;Yousef Neyshabouri;Armin Miremad;Saeid Ahmadi;Hossein Iman-Eini;
      Pages: 9952 - 9960
      Abstract: In this article, we introduce a model predictive control with optimal switching sequence (OSS-MPC) for a multilevel static synchronous compensator (STATCOM). The studied STATCOM is based on a hybrid multilevel inverter named HC-FNPC formed by the cascaded connection of H-bridge cells with a full-bridge neutral point clamped cell (FNPC). In this article, the optimal switching sequences are derived for HC-FNPC STATCOM by considering the impact of each switching sequence on the voltage of capacitors. Then, the control objectives of hybrid multilevel STATCOM, i.e., ac current control and capacitors’ voltages balancing, are formulated in terms of OSS-MPC for the first time. In contrast to the conventional MPC, this method provides a fixed-switching frequency. Also, by a combination of optimal switching sequences in MPC, the regulation of capacitors’ voltages with unequal values is realized. The control system's performance is verified on a nine-level (9L) 2.4 Mvar/11 kV HC-FNPC STATCOM in MATLAB/Simulink. Also, the experimental results are provided on a 9L 1.25 kvar/220 V scaled-down hardware prototype.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • A Gate Driving Strategy for the Series-Connected IGBTs to Improve the
           Resilience Against IGBTs Short-Circuit Failures

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      Authors: Sadegh Mohsenzade;
      Pages: 9961 - 9971
      Abstract: The application of series-connected insulated gate bipolar transistors (IGBTs) is becoming widespread in high-voltage/power converters. The reliable operation of the resulted series high-voltage switch (RSHVS) is of considerable importance. This article investigates the effect of the IGBTs single short-circuit failure on the performance of RSHVS. It will be revealed that the gate drive system dedicated to command the series-connected IGBTs has the main role in spreading these prevail failures to the others. Consequently, the operation of RSHVS is interrupted in such common failures. Hence, extant gate drive systems are very fragile against this type of failure. To overcome this issue, this article proposes a gate drive system with resilience against IGBTs short-circuit failure. The proposed gate drive system does not spread the single failures to the other healthy IGBTs. Thereby, the interrupted operation of RSHVS as well as the cascaded failure in the whole of IGBTs are avoided. Results indicate at least 40% improvement in the meantime to failure of RSHVS with respect to the extant strategies. In addition, the power loss should be accepted for the safe voltage condition of IGBTs decreased considerably in the proposed approach. The performance of the proposed approach is evaluated using simulations and experiments.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Intermediate Coil-Aided Wireless Charging Via Interactive Power
           Transmitting With Misalignment-Tolerating Considerations

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      Authors: Shyh-Jier Huang;Tsong-Shing Lee;Ya-Ming Yang;Jeng-Yi Chen;
      Pages: 9972 - 9983
      Abstract: This article proposes an intermediate coil-aided wireless charging systems via interactive power transmitting mechanism. The study is motivated because the occurrence of coil misalignment is known to affect the transfer efficiency and may destabilize the output voltage. The article is, hence, devoted to designing auxiliary repeater-aided coil module along with interoperable power adjustment, anticipating enhancing the tolerating capability of misalignment during the wireless charging. The design of this system includes two half-bridge inverters deployed to drive main transmitting coil and repeater coil. Circuit operations consist of repeater-aided mode and power-interactive mode. An interoperable power-transmitting strategy is applied to regulate the gain following the movement of receiving coils, by which a higher efficiency is ensured while a constant voltage is better maintained. To confirm the effectiveness of this design approach, both circuit simulation and hardware realization are accomplished under different test scenarios. Experimental outcome support the practicality of the approach, serving as beneficial references for wireless charging applications.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • High Step-Down Bridgeless Sepic/Cuk PFC Rectifiers With Improved
           Efficiency and Reduced Current Stress

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      Authors: Mohammad Babaei;Mohammad Monfared;
      Pages: 9984 - 9991
      Abstract: In this article, two high step-down bridgeless power factor correction rectifiers based on the switched inductor network (SIN) are introduced. The proposed rectifiers employ the SIN to provide high step-down voltage gain with a higher duty cycle than the competitors. They also offer higher efficiency, lower current stress, and total peak switching device powers. A thorough and straightforward design algorithm in the discontinuous conduction mode is provided that ensures a unity power factor and a low total harmonic distortion with a simple control scheme. As a demonstration of the superior performance of the proposed rectifiers, a 300-W high-gain sepic rectifier setup with 48Vdc output voltage from a 230Vrms/50Hz source is built in the laboratory.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Permanent Emergency LED Lamp Based on a Series Single-Switch Resonant
           Converter With Battery Clamp

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      Authors: Pablo Quintana-Barcia;Javier Ribas;Francisco A. Juarez-Leon;Diego Rodriguez-Fuertes;
      Pages: 9992 - 10000
      Abstract: Permanent emergency lighting is a safety device whose lamp is always on and continues to operate when a mains failure occurs. The circuit has to charge the battery and drive the lamp while the grid is present and keep the lamp running from the battery in case of mains failure. This might require up to three different converters: front-end converter, electronic ballast, and battery charger. Since an emergency lamp must be on for as long as the local regulations require during a grid failure, efficiency is key. This article presents a permanent emergency lamp based on a series resonant current regulator that operates both as a ballast and as a battery charger. In this circuit, the power converter is placed in series with the LED array, operating as a controllable nondissipative impedance. A methodology based on the study of energy balances during resonant operation intervals is presented, aiming to design and build a laboratory prototype with low component count and high efficiency.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • A Dual Shunt Inductor Compensated IPT System With Nearly Unity Power
           Factor for Wide Load Range and Misalignment Tolerance

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      Authors: Shiying Luo;Zirui Yao;Zhuhaobo Zhang;Guanxi Li;Xin Zhang;Hao Ma;
      Pages: 10001 - 10013
      Abstract: In inductive power transfer systems, load and coupling fluctuations may cause significant reactive power. In this article, a dual shunt inductor compensation topology (named as L-S/S-L) with parallel inductors at both ports of the series/series compensation is proposed to maintain nearly unity power factor and implement a wide load range with considering misalignment. With the balanced parameter configuration, L-S/S-L compensation can keep a constant zero phase angle. This feature maintains nearly unity power factor under load, coupling, and frequency variations. A monotonically rising power versus frequency characteristic can be designed by setting the scale factors of L-S/S-L. Based on the designed characteristic, frequency control is implemented to adjust the output power over a wide range. Furthermore, zero voltage switching is achieved within the selected operating frequency range by slightly adjusting the primary shunt inductance in the design stage. A 2.1 kW prototype is built to demonstrate the validity of the proposed method. Experimental results show that the power factor is close to unity under various working conditions. Within the coupling coefficient range from 0.35 to 0.16, the maximum efficiency changes little from 95.6% to 94.7%.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Digital Control of Multiphase Series Capacitor Buck Converter Prototype
           for the Powering of HL-LHC Inner Triplet Magnets

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      Authors: Edorta Ibarra;Antoni Arias;Iñigo Martínez de Alegría;Alberto Otero;Louis de Mallac;
      Pages: 10014 - 10024
      Abstract: A major upgrade will be conducted in the Large Hardon Collider (LHC) at CERN. This high-luminosity (HL) version of the LHC will increase the nominal luminosity by a factor of five. One of the key technologies of the HL-LHC is the new superconducting inner triplet (IT) magnets, responsible of producing high magnetic fields to focus particle beams. To power the IT magnets from the grid, a multistage power supply with an intermediate 24-V battery pack is being considered. In such topology, a low-voltage high-current dc/dc converter operating with a very high step-down ratio is required for the final conversion stage. In this work, an interleaved multiphase series capacitor buck converter is proposed to feed the IT magnets from the battery pack. A novel voltage regulation approach that ensures the current balance between the paralleled series capacitor cells is also proposed, where one cell is responsible for the output voltage regulation, while the remaining cells are current-regulated. A balanced current sharing between the series capacitor cells is achieved, when the current-controlled cells are referenced by the actual current of the first one. The proposal is theoretically analyzed and experimentally validated in a six-cell 1000-A prototype unit.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Synthesis of Dual-Output DC−DC Converters With Coupled Inductor From a
           Generalized Output Branch

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      Authors: Zhiqiang Li;Ruichi Wang;Yuwei Liu;Guipeng Chen;
      Pages: 10025 - 10034
      Abstract: A generalized output branch with coupled inductor is proposed in this article, with which a diversity of single-input dual-output (SIDO) configurations can be synthesized through substituting it for the original inductor in the conventional single-input single-output (SISO) converters. Furthermore, for each configuration, multiple SIDO converters will be generated after realizing the auxiliary voltage source in the generalized output branch with two different nodes. Because the number of magnetic components remains unchanged in comparison with the SISO converter, high power density can be achieved in the derived SIDO converters with coupled inductor. Moreover, the cross-regulation problem is effectively alleviated, and soft-switching operation is realized for switches. Hence, both optimized steady-state and dynamic performance can be obtained. In this article, three example SIDO configurations based on buck, boost, and buck−boost converters are derived, and an example family of 12 SIDO converters from buck converter is demonstrated in detail. Afterwards, a unified operation principle and performance analysis suitable for all these 12 converters are also introduced, which is helpful for the topology comparison. Finally, experimental verification of the theoretical analysis is also conducted.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • GaN-Based Two-Stage Converter With High Power Density and Fast Response
           for Pulsed Load Applications

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      Authors: Yu Yao;Gnana Sambandam Kulothungan;Harish Sarma Krishnamoorthy;Amitava Das;Harshit Soni;
      Pages: 10035 - 10044
      Abstract: This article proposes a two-stage power converter with novel control methods for pulsed load applications. The first stage is an isolated converter that transfers only average power to the second stage, which dramatically reduces the input filter size and components’ current rating. The second stage is a buck converter designed for a fast response during pulsed load transients. A flexible intermediate voltage is implemented to reduce the size of the midpoint energy storage capacitor that is responsible for compensating the instantaneous power difference between the two stages. A novel digital input feed-forward controller is proposed for the second stage to eliminate the poor line regulation issue caused by the flexible intermediate voltage. To verify the effectiveness of the two-stage power supply and the control methods, a full-scale 800 W (average)/4 kW (peak) converter prototype is built and tested. The results prove the feasibility of the proposed topology as well as control methods and demonstrate the advantages over traditional concepts.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Cylindrical Transmitting Coil for Two-Dimensional Omnidirectional Wireless
           Power Transfer

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      Authors: Nam Ha-Van;Yining Liu;Prasad Jayathurathnage;Constantin R. Simovski;Sergei A. Tretyakov;
      Pages: 10045 - 10054
      Abstract: Megahertz-range wireless power transfer has become a promising approach for increasing spatial freedom of charging. This article proposes a cylindrical-shaped coil, which can produce the homogeneous magnetic field in a plane. The coil consists of two helical windings, which are wound to guide the current in opposite directions. A single power source is used to excite the transmitter without any current amplitude or phase control circuits. Furthermore, since the parasitic capacitance of the coil is not negligible due to the complexity of the coil shape, we develop a general equivalent model with parasitic capacitance for the analysis of complex coils. The system efficiency of the proposed omnidirectional wireless power transfer device is validated by a practical experiment. The measured dc-to-dc efficiency of approximately 72.4% and the load power of 13 W are demonstrated for the proposed wireless charging system at 6.78-MHz operating frequency. Finally, we verify that the electromagnetic exposure satisfies the safety regulations.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • A Hybrid Modular Interline Current Flow Controller for Meshed HVDC Grids

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      Authors: Shuxin Zhang;Binbin Li;Wei Wang;Yujie Zhang;Dianguo Xu;Gen Li;Jun Liang;
      Pages: 10055 - 10065
      Abstract: In meshed high-voltage direct current (HVdc) grid, the current flows through the lines cannot be controlled with sufficient freedom without additional power electronics-based devices, namely current flow controller (CFC). In this article, a novel hybrid modular interline CFC is proposed based on H-bridge submodules and thyristor valves. Due to its modularity, the proposed CFC is particularly suitable for applications requiring high voltage and large power capacity. The circuit structure, operation principle, and parameter design are presented. In addition, a control strategy is developed for the proposed CFC. Simulations are carried out using a four-terminal meshed HVdc grid to verify the effectiveness of the topology and its control strategy. A downscaled prototype is built, which further validates the proposed CFC.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Double-Vector Model-Free Predictive Control Method for Voltage Source
           Inverter With Visualization Analysis

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      Authors: Nan Jin;Mo Chen;Leilei Guo;Yanyan Li;Yafei Chen;
      Pages: 10066 - 10078
      Abstract: Strong parameter dependence and large current ripple are two shortcomings that obstruct the development of model predictive control for voltage source inverters (VSIs). To solve these problems, in this article,a double-vector model-free predictive control (MFPC) method for VSI with visualization analysis is proposed. First, the ultralocal model of the VSI is established and a full-order sliding model observer is designed to estimate the lumped disturbance. MFPC is achieved with enhanced parameter robustness. Then, a double-vector MFPC method is further proposed. By applying two vectors per control period, the current ripple is reduced significantly. A detailed visualization analysis method is proposed, which verifies the effectiveness of the proposed double-vector MFPC method in theory. Besides, the proposed visualization analysis method has the potential to be used to analyze the effectiveness of other types of multivector model predictive control method with different cost functions. Detailed comparative experimental studies verify the effectiveness of the proposed double-vector MFPC method.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • A Multivariable Phase-Locked Loop-Integrated Controller for Enhanced
           Performance of Voltage Source Converters Under Weak Grid Conditions

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      Authors: Seyed Milad Hoseinizadeh;Houshang Karimi;Masoud Karimi-Ghartemani;Saeed Ouni;
      Pages: 10079 - 10089
      Abstract: This article proposes a new control strategy in stationary frame to improve the operational robustness of voltage source converters (VSCs) under weak grid conditions. First, dynamics of the phase-locked loop (PLL) are incorporated into the model of a grid-connected VSC in stationary reference frame. It is rigorously shown that the three-phase PLL introduces cross-coupling terms between the two control channels. Second, based on the augmented model, a multivariable controller is proposed which combines the current control feedback gains with PLL feedback gains. Third, the gains of the controller are designed using an optimal control theory approach. It is shown through theoretical analysis, computer simulations, and a laboratory experimental setup that the proposed controller improves the stability margins of the VSC during weak grid conditions. More specifically, under a given identical operating conditions, while the conventional controller’s responses become increasingly oscillatory for short-circuit ratio (SCR) below 1.95 and eventually becomes unstable at SCR=1.26, the proposed controller exhibits smooth and stable responses for SCR as low as 1. The proposed controller also produces cleaner sinusoidal currents during unbalanced grid voltages.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • A Quadratic Quasi-Z-Source Full-Bridge Isolated DC–DC Converter With
           High Reliability for Wide Input Applications

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      Authors: Emmanuel S. Oluwasogo;Honnyong Cha;
      Pages: 10090 - 10100
      Abstract: In this article, two configurations of the quadratic quasi-Z-source (Q-qZS) isolated dc–dc converters are presented, namely continuous input current and discontinuous input current configurations. The operating principles and steady state of the continuous input current topology analyzed in this article is characterized with the following features: 1) wider operating range due to buck and boost functions in a single stage; 2) draws continuous input current; 3) low input current ripple compared with other qZS-based isolated dc–dc converters; 4) better reliability and good immunity against EMI noise; 5) common ground between the input source and the inverting bridge; and 6) continuous control over the entire operating range. Compared with other qZS-based isolated dc–dc converters, lower current stresses on active and passive components used are realized. Hence, the total magnetic volume/energy required by the proposed converter is reduced with the potential of achieving high power density. A prototype of 40–140 V input voltage, 300 V output, and 550 W rated power is developed to validate the performance of the proposed converter presented.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Research on the Characteristics of a High-Temperature Superconducting
           Leakage Flux-Controlled Reactor

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      Authors: Shifeng Shen;Xusheng Wu;Sinian Yan;Xiaona Wang;Li Ren;Xianglie Yi;Yang Liu;
      Pages: 10101 - 10111
      Abstract: To realize the precise application of controllable reactors in power systems,research on the characteristics of controllable reactors is essential. A high-temperature superconducting leakage flux-controlled reactor (HTS-LFCR) based on the principle of a high-leakage reactance transformer was proposed in our previous research. In this article, with the development and testing of a 380-V prototype of an HTS-LFCR, the characteristics of the HTS-LFCR are thoroughly studied. The detailed electromagnetic design of the prototype is introduced. As the prototype works at various voltages, the basic characteristics, including the reactance, harmonics, and loss, are analyzed. Moreover, through experiments on an ordinary reactor with the same structure and principles as the HTS-LFCR, and through the comparison of some commercial reactors, the advantages of the HTS-LFCR are verified. The dc component of the current in the HTS control windings during a transient process is also researched and verified through experiments. The research in this article can provide some references for the precise application of the HTS-LFCR in power systems.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • High Step-Up Switched-Capacitor Active Switched-Inductor Converter With
           Self-Voltage Balancing and Low Stress

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      Authors: Chaofan Cui;Yu Tang;Yingjun Guo;Hexu Sun;Lin Jiang;
      Pages: 10112 - 10128
      Abstract: High step-up dc–dc converters are widely used in new energy applications such as photovoltaic cell, fuel cell, dc microgrid, etc. Active switched-inductor (ASL) converter has simple operation and low stress on switches. To further increase the voltage gain, some SC (switched-capacitor)/ASL step-up converters have been proposed recently. However, these SC/ASL step-up converters have voltage oscillation on switches, which leads to the voltage stress on switches is higher than the theoretical value. In this article, a novel high step-up SC/ASL converter is proposed. Compared with other SC/ASL step-up converters, the proposed converter has lower voltage stress on the switches, output diodes, and output filter capacitors, and the efficiency is higher. In addition, the proposed converter can achieve self-voltage balancing on switches. This article analyzes the proposed converter from operation principle, continuous conduction mode (CCM) analysis, CCM operation with unbalanced inductors, input current ripple analysis, discontinuous conduction mode and boundary conduction mode analysis, switches self-voltage balancing characteristic, voltage stress, current stress, comparison analysis, and design considerations. Finally, a 200 W, 25–45 V/380 V, 50 kHz experimental prototype has been established in the laboratory to evaluate the proposed converter, which reached a peak efficiency of 97.3%.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Hierarchical Pigeon-Inspired Optimization-Based MPPT Method for
           Photovoltaic Systems Under Complex Partial Shading Conditions

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      Authors: Zhuoli Zhao;Mingyu Zhang;Zehan Zhang;Yuewu Wang;Runting Cheng;Juntao Guo;Ping Yang;Chun Sing Lai;Peng Li;Loi Lei Lai;
      Pages: 10129 - 10143
      Abstract: This article proposes a novel maximum power point tracking (MPPT) method based on the variant of the pigeon-inspired optimization (PIO) algorithm for photovoltaic systems under partial shading conditions (PSCs). The proposed method integrates the hierarchical network behavior of pigeon flock and revises the map and compass operator of the original PIO algorithm to improve optimization efficiency. In addition, the landmark operator is used to perform a small-scale search to achieve fast tracking. Based on the combination of these mechanisms and dual-mode dynamic tracking scheme, the proposed hierarchical pigeon-inspired optimization (HPIO) MPPT method has a powerful search ability to deal with PSCs. To verify the superiority of the proposed HPIO MPPT method, it is compared with other existing advanced MPPT methods in simulation and experiments. Compared with traditional MPPT techniques based on artificial intelligence, the proposed HPIO MPPT method has a higher success rate in tracking GMPP and excellent tracking speed under PSCs. And the HPIO method also shows excellent performance under complex PSC with multiple clusters and load-variation conditions.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Effect of Pulsed Current on Charging Performance of Lithium-Ion Batteries

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      Authors: Xinrong Huang;Wenjie Liu;Anirudh Budnar Acharya;Jinhao Meng;Remus Teodorescu;Daniel-Ioan Stroe;
      Pages: 10144 - 10153
      Abstract: The pulsed current has been proposed as a promising battery charging technique to improve the charging performance and maximize the lifetime for lithium-ion (Li-ion) batteries. However, the effect of the pulsed current charging is inconclusive due to the changeable current mode and conditions. This article systematically investigates the effect of various pulsed current charging modes, i.e., positive pulsed current mode, pulsed current-constant current mode, negative pulsed current mode, alternating pulsed current mode, sinusoidal-ripple current mode, and alternating sinusoidal-ripple current mode on battery performance. Moreover, a comprehensive analysis of the frequency impact on the quality of the current mode is performed. The current modes in this work are evaluated considering the maximum rising temperature, discharging capacity, and charging speed according to experimental results. Furthermore, this work provides guidance for developing pulsed current charging strategies to satisfy future charging requirements.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • A Free-Rotation Asymmetric Magnetic Coupling Structure of UAV Wireless
           Charging Platform With Conformal Pickup

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      Authors: Zhi Bie;Jiantao Zhang;Kai Song;De'an Wang;Chunbo Zhu;
      Pages: 10154 - 10161
      Abstract: This article proposes an asymmetric magnetic coupler using the horizontal magnetic field to realize the conformal and lightweight unmanned aerial vehicle (UAV) side pickup mechanism and solve the problems of rotation misalignment and horizontal offset of UAVs. The novel structure uses multiple groups of series circular coils as the transmitting coil to construct a uniform near harness horizontal magnetic field. The solenoid structure covered with flexible magnetic material is used as the receiver, which is attached to the UAV landing gear. A 200-W prototype is produced to validate the proposed structure. The system can maintain smooth mutual inductance with a dc–dc efficiency of 90% under a ±20 mm offset and free-rotation.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • A High Step-Up Transformerless DC–DC Converter With New Voltage
           Multiplier Cell Topology and Coupled Inductor

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      Authors: Pouria Sarvghadi;Ali Yazdian Varjani;Mahdi Shahparasti;
      Pages: 10162 - 10171
      Abstract: In this article, a new high step-up transformerless dc–dc converter based on a voltage multiplier and a coupled inductor topology is presented. The proposed converter has two stages. In the first stage, a modified boost converter is designed by the coupled inductor, and in the second stage, a new voltage multiplier by using a coupled inductor is illustrated. In this converter, high voltage gain can be achieved by adjusting the turn ratio of two coupled inductors and the duty cycle, which result in three degrees of design freedom. Using a single power switch with low on-resistance in the converter structure leads to simple control and low conduction loss. In addition, total voltage stresses of active elements are decreased, which increases efficiency. Steady-state performance and theoretical achievements are confirmed by experimental test results on a test setup with one 200-W dc–dc prototype.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Self-Powered Single-Inductor Rectifier-Less SSHI Array Interface With the
           MPPT Technique for Piezoelectric Energy Harvesting

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      Authors: Zhihe Long;Pengyu Li;Jun Chen;Henry Shu-Hung Chung;Zhengbao Yang;
      Pages: 10172 - 10181
      Abstract: Piezoelectric energy harvester (PEH) arrays are practical solutions to the low and unreliable power output of a single PEH. However, most PEH circuits are developed for addressing the one-channel ac input from a single PEH. In this article, an extensible rectifier-less synchronized switch harvesting on inductor (ReL-SSHI) array interface with the maximal power point tracking (MPPT) function to manage the multiple ac inputs from the PEH arrays is designed. The ac–dc conversion is performed by the ReL-SSHI topology with passive peak switches featured with self-powered characteristic and fast cold-start. Only one shared inductor is employed, greatly reducing the circuit volume and cost. The MPPT module for each channel is implemented by a simple envelope detector and an ultra-low power hysteresis controller and achieves continuous energy extraction by adapting the fractional normal-operation voltage method. A developed discrete array interface able to handle three PEHs effectively executes the MPPT for each channel with the uphill and downhill response speeds of 2.0 and 7.1 V/s, and a maximal MPPT efficiency of 97.1%. This circuit boosts the power output by 485% compared with that by the traditional full-bridge rectifier, around 33% higher than that from existing synchronous electric charge extraction array interfaces.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Global Stability Analysis for Synchronous Reference Frame Phase-Locked
           Loops

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      Authors: Zhiyong Dai;Guangqi Li;Mingdi Fan;Jin Huang;Yong Yang;Wei Hang;
      Pages: 10182 - 10191
      Abstract: This article analyzes the global stability of synchronous reference frame phase-locked loops (SRF-PLLs) from a large signal viewpoint. First, a large-signal model of SRF-PLL is accurately established, without applying any linearization method. Then, according to the phase portrait and Lyapunov argument, the global performance of SRF-PLL is discussed in the nonlinear frame. Compared with the small-signal analysis methods, the proposed analysis, not relying on the small-signal model and linearization method, provides a global discussion of the SRF-PLL performance. The contributions of this article are as follows. First, it is found that SRF-PLL has infinite equilibrium points, including stable points and saddle points. Second, it provides a way to divide the global region of SRF-PLL into many small regions. In each small region, the SRF-PLL only has one stable equilibrium point. And for any initial states $(tilde{theta }(t_0),tilde{omega }(t_0))$ in a small region, all states $(tilde{theta }(t),tilde{omega }(t)),t>t_0$ will remain in this small region, and SRF-PLL will converge to the unique stable equilibrium point of this small region. Third, by dividing the global region of SRF-PLL into many small regions, it is found that when the frequency of grids varies largely, the SRF-PLL will converge to a new equilibrium point that is far away from the original equilibrium point. It is the reason why the frequency convergence of SRF-PLL has many oscillations and SRF-PLL has a rather slow dynamic, when the frequency changes largely. The experimental results are provided to verify the proposed global stability analysis of SRF-PLL.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • A Robust Fractional-Order Control Technique for Stable Performance of
           Multilevel Converter-Based Grid-Tied DG Units

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      Authors: Ali Zafari;Majid Mehrasa;Seddik Bacha;Kamal Al-Haddad;Nasser Hosseinzadeh;
      Pages: 10192 - 10201
      Abstract: In this article, we propose a sliding fractional-order (FO) control strategy to provide robustness feature for integrating a multilevel converter into the power grid under the system parameter uncertainties, nonlinear load alterations, and grid voltage sag. All dynamics achieved from the input capacitors and output inductances of the multilevel converter are utilized to design the proposed sliding fractional surfaces (SFSs) such that a robust operation of the grid-tied converter-based system is achieved. Then, an SFS-based Lyapunov function is built to assess the proposed controller stability. A thorough analysis of the Lyapunov function is carried out for distinguishing suitable boundaries of the controller coefficients when the error components of the system state variables are changed, accordingly. Using the derivative of Lyapunov function and SFS, a comprehensive evaluation is executed to detail the regulation procedure for the robustness and fractional PI controller coefficients. Finally, a closed-loop system using the converter current dynamics aims to discern the differences between different values of FO. Experimental tests using dSPACE-1202 along with MATLAB/Simulink simulations are employed to verify the effectiveness of the proposed control technique for providing proper harmonic compensation, enhanced power quality, unity power factor, voltage sag tolerance, and very low total harmonic distortion grid current.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Power Oscillation Suppression of Multi-VSG Grid via Decentralized Mutual
           Damping Control

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      Authors: Siqi Fu;Yao Sun;Lang Li;Zhangjie Liu;Hua Han;Mei Su;
      Pages: 10202 - 10214
      Abstract: Virtual synchronous generator (VSG) control introduces active power oscillation especially under the condition of multi-VSG. This article proposes a decentralized mutual damping control method that suppresses power oscillation in the multi-VSG grid. The idea is that as the local frequency is greater than the frequency of the VSG other than itself, the input energy of the local VSG is reduced, and thus dωi/dt increases. On the contrary, when the local frequency is less than others, the input energy is increased, and thus dωi/dt decreases. In this way, all frequencies get close to each other in the dynamic process with the method. The idea is verified by the stability analysis. Participation factor analysis and sensitivity analysis are presented to guide parameter design. Finally, the effectiveness of the decentralized mutual damping method is verified through the simulation results and experimental results.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Decentralized Mutual Damping Control of Cascaded-Type VSGs for Power and
           Frequency Oscillation Suppression

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      Authors: Lang Li;Yao Sun;Mei Su;Siqi Fu;
      Pages: 10215 - 10226
      Abstract: This article reveals the power and frequency oscillation mechanism of the islanded cascaded-type virtual synchronous generators (VSGs), and proposes a decentralized mutual damping suppression method. In the proposed scheme, the mutual damping term is constructed via the decentralized manner with transmission line current. It contributes to increasing damping and accelerating the frequency convergence of cascaded-type VSGs in the dynamic process. As a result, the power and frequency oscillations are restrained, and the system dynamic performance is improved. Further, the system stability based on the Lyapunov energy function method is proved. Finally, the effectiveness of the proposed decentralized mutual damping control is verified by simulations and experimental results.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Two-Dimensional Spatial Construction for Online Modeling of Distributed
           Parameter Systems

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      Authors: Peng Wei;Han-Xiong Li;
      Pages: 10227 - 10235
      Abstract: A 2-D spatial construction method is proposed for the online modeling of distributed parameter systems (DPSs), such as battery thermal process. The proposed method can combine the advantages of spectral method and Karhunen–Loève decomposition (KLD) method. First, the continuous spatial basis functions are designed by the 2-D spatial construction to keep the information between sensing locations. With the 2-D space-time separation and recursive learning, the derived model can preserve the couplings between spatial dimensions and update over time. The radial basis function network is utilized to identify the low-dimensional temporal dynamics. After the space-time synthesis, the constructed spatiotemporal model can provide continuous modeling of the DPS with satisfactory performance. Convergence analysis has been carried out, which proves that the proposed method can guarantee bounded errors. Finally, simulations and experiments on a pouch-type lithium-ion battery with unknown partial differential equations prove the effectiveness of the proposed method.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Mitigation of Subsynchronous Resonance for Grid-Connected Inverters in
           Series-Compensated Weak Power Grids Through Observed Q-Axis Grid Voltage
           Feedback

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      Authors: Kai Wang;Xibo Yuan;Hui Wang;Shanglong Li;Xiaojie Wu;
      Pages: 10236 - 10248
      Abstract: Series compensations have been widely used in modern power systems to extend the power transfer capacity. Since more and more renewable power generation systems are installed in power systems, the grid-connected inverters (GCIs) used by the renewable power generations may interfere with series-compensated power lines, which introduce subsynchronous resonance (SSR) causing power system failure that has been observed in real cases. The phase-locked loop (PLL) of the GCI's control system is the main factor that can cause the SSR in the series-compensated power grid. To mitigate the impact of the PLL and obtain the stable operation of the power system, a q-axis voltage feedback method has been proposed in literature to damp the harmonic oscillations in the weak power grid where, however, the series compensation is not considered. Because the real q-axis voltage cannot be obtained, the q-axis voltage output from the PLL is used as the feedback variable in literature. However, due to the dynamic response of the PLL, the q-axis voltage output from the PLL is different from the real q-axis voltage, and the direct use of it for the damping of the SSR in the power grid with series compensations is invalid, which is investigated in this article. Besides, an observed q-axis voltage feedback method is proposed in this article to damp the SSR in the series-compensated power grid with GCIs being connected. By putting an observer in the q-axis voltage feedback path, the real q-axis voltage can be estimated and applied to damp the SSR. Simulation and experimental results have been provided to verify the effectiveness of the proposed observed q-axis voltage feedback method in the damping of the SSR.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • A High Step-Up DC–DC Converter With Three-Winding Coupled Inductor for
           Sustainable Energy Systems

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      Authors: Tsorng-Juu Liang;Peng Luo;Kai-Hui Chen;
      Pages: 10249 - 10258
      Abstract: This article proposes a high step-up dc–dc converter with a continuous input current that is suitable for sustainable energy systems. A three-winding coupled inductor, two power switches, three diodes, and three capacitors are utilized to perform the functions of active switched inductor and switched capacitor. By charging the two primary windings in parallel, and discharging the two primary windings in series to the intermediate capacitor and the output, the conversion ratio can be further improved with lower voltage stresses and current stresses on its power switches. In addition, the energy stored in the leakage inductance is recycled to reduce the voltage spikes of the power switches. Eventually, a laboratory prototype with an input voltage of 36–48 V, and output voltage of 400–600 V with a rated power of 600 W is implemented to validate the correctness and effectiveness of the theoretical analyses. The maximum efficiency and full load efficiency are 97% and 96.2%, respectively.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Hybrid Robotic Manipulator Using Sensorized Articulated Segment Joints
           With Soft Inflatable Rubber Bellows

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      Authors: Babar Jamil;Gyeongjae Yoo;Youngjin Choi;Hugo Rodrigue;
      Pages: 10259 - 10269
      Abstract: Robotic manipulators have been used inindustry for decades. However, their heavy mass and rigidity make them unsuitable for environments where they may coexist with humans. This has spurred interest in robotic arms with compliance in their joints using methods, such as impedance control. However, inherent compliance is safer, less computationally expensive, and does not require complex sensing solutions. In this article, the design of a sensorized hybrid hard-soft articulated joint using inflatable soft rubber bellows for actuation and simple angular potentiometers for angular position sensing is presented. The joint is hybrid in the sense that it combines rigid motion with soft actuation. This design allows for a simple yet effective solution that combines the precise sensing of rigid manipulators with the compliance of soft ones. Closed-loop control of this joint was implemented and it was capable of following a given trajectory while rejecting disturbances. This design was then extended to a two degrees of freedom (DOFs) joint with the path following capability, and then, integrated with a rigid base joint to form a 6-DOFs hybrid robotic manipulator for use in small retail businesses. This manipulator can handle payloads up to 1 kg over a large work area and was tested for pick-and-place operations.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Model-Free Saturated PD-SMC Method for 4-DOF Tower Crane Systems

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      Authors: Menghua Zhang;Xingjian Jing;
      Pages: 10270 - 10280
      Abstract: In this article, we design a novel saturated proportional-derivative (PD) with sliding-mode control (SMC) method or saturated PD-SMC in short for 4-DOF tower crane systems under uncertain dynamics, external disturbances, as well as saturated control input constraints. The designed control method is model free, which can achieve accurate positioning and rapid swing suppression and elimination using only jib/trolly position/velocity and payload swing feedback with limited control inputs. Different from the existing control methods, the designed control method takes the advantages of simple structure and being easily realized in practical applications of the PD control, strong robustness of the SMC method with respect to model uncertainties and external disturbances, avoiding the requirements of accurate model knowledge associated with the SMC method, as well as rapid payload swing reduction of the swing suppression control. The stability of the controlled system is ensured by rigorous Lyapunov-based analysis. To the best of our knowledge, this is the first model-free control method without any linearization operations for tower crane systems with uncertain dynamics, external disturbances, and saturated control input constraints. Several experimental results are given to validate the superior control performance and strong robustness of the designed control method.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Efficient MSPSO Sampling for Object Detection and 6-D Pose Estimation in
           3-D Scenes

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      Authors: Xuejun Xing;Jianwei Guo;Liangliang Nan;Qingyi Gu;Xiaopeng Zhang;Dong-Ming Yan;
      Pages: 10281 - 10291
      Abstract: The point pair feature (PPF) is widely used in manufacturing for estimating 6-D poses. The key to the success of PPF matching is to establish correct 3-D correspondences between the object and the scene, i.e., finding as many valid similar point pairs as possible. However, efficient sampling of point pairs has been overlooked in existing frameworks. In this article, we propose a revised PPF matching pipeline to improve the efficiency of 6-D pose estimation. Our basic idea is that the valid scene reference points are lying on the object’s surface and the previously sampled reference points can provide prior information for locating new reference points. The novelty of our approach is a new sampling algorithm for selecting scene reference points based on the multisubpopulation particle swarm optimization guided by a probability map. We also introduce an effective pose clustering and hypotheses verification method to obtain the optimal pose. Moreover, we optimize the progressive sampling for multiframe point clouds to improve processing efficiency. The experimental results show that our method outperforms previous methods by 6.6%, 3.9% in terms of accuracy on the public DTU and LineMOD datasets, respectively. We further validate our approach by applying it in a real robot grasping task.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Parametric PH Curves Model Based Kinematic Control of the Shape of Mobile
           Soft Manipulators in Unstructured Environment

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      Authors: Steeve Mbakop;Gilles Tagne;Sergey V. Drakunov;Rochdi Merzouki;
      Pages: 10292 - 10300
      Abstract: Mobile soft continuum manipulator (MSCM) is more and more used in various applications of everyday life, such as logistics, farming, medical diagnosis, medical therapy, bakery, human collaboration, etc. However, the control of its shape remains a major challenge, especially when it is navigating in an unstructured environment. In this contribution, a kinematic-model-based shape control is designed in the space configuration for an MSCM, allowing its autonomous navigation in the presence of obstacles. For that purpose, the shape kinematic modeling is realized using a parametric spatial Pythagorean hodograph (PH) curve with a predefined length, whereas the artificial potential field algorithm acts on the control points of the PH curve for shape adaptation in presence of obstacles. The novelty of the proposed work resides in the use of parametric curve formalism to model the shape of an infinite degree of freedom mobile soft manipulator robot and its kinematic control by optimizing its bending potential energy during its motion. The shape optimization based on a minimal bending energy during the collision-free path is respecting a sliding mode strategy applied to the PH curve control points. Experimental results are obtained using a class of MSCM called RobotinoXT. These experiments show the advantages of using a reduced kinematic model based on PH curve to control the MSCM shape in dynamic motion.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • A Simultaneous Learning and Control Scheme for Redundant Manipulators With
           Physical Constraints on Decision Variable and Its Derivative

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      Authors: Mei Liu;Jialiang Fan;Yu Zheng;Shuai Li;Long Jin;
      Pages: 10301 - 10310
      Abstract: In this article, a simultaneous learning and control scheme built on the joint velocity level with physical constraints on the decision variable and its derivative, i.e., joint angle, joint velocity, and joint acceleration constraints, is proposed for the redundant manipulator control. The scheme works when the structure parameters involved in the forward kinematics are unknown or implicit. The learning and control parts are incorporated simultaneously in the scheme, which is finally formulated as a quadratic programming problem solved by a devised recurrent neural network (RNN). The convergences of learning and control abilities of the RNN are proved theoretically. Simulations and physical experiments on a 7-degrees of freedom (DOFs) redundant manipulator show that, aided with the proposed scheme and the related RNN solver, a redundant manipulator with unknown structure parameters can perform a given inverse kinematics task with high accuracy while satisfying physical constraints on the decision variable and its derivative.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Velocity-Tracking Control Based on Refined Disturbance Observer for Gimbal
           Servo System With Multiple Disturbances

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      Authors: Yangyang Cui;Jianzhong Qiao;Yukai Zhu;Xiang Yu;Lei Guo;
      Pages: 10311 - 10321
      Abstract: Multiple disturbances are the main constraints that hinder the high-performance velocity tracking of the gimbal servo system in control moment gyro. This article presents a non-cascade structured velocity-tracking controller based on a refined disturbance observer for handling multiple disturbances and improve the tracking performance. Specifically, a disturbance observer is designed to estimate the imbalance disturbance, which can be represented by an exogenous system. The disturbances that cannot be modeled a priori are treated as a lumped term and estimated via extended state observer. By resorting to disturbance estimation, a novel sliding mode controller based on the disturbance estimation values is developed to handle the mismatched problem and chattering issue. Finally, experimental tests are conducted to verify the effectiveness of the proposed anti-disturbance control scheme.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Robust Fixed-Time Sliding Mode Attitude Control of Tilt Trirotor UAV in
           Helicopter Mode

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      Authors: Li Yu;Guang He;Xiangke Wang;Shulong Zhao;
      Pages: 10322 - 10332
      Abstract: In this article, we address the problem of robust fixed-time attitude stabilization for tilt trirotor unmanned aerial vehicle subjects to parameter uncertainties and external disturbances. First, a novel fixed-time stable system with a faster convergence rate is proposed. Second, a nonsingular fixed-time sliding mode surface is developed, which has better convergence performance than existing methods. Third, a continuous fast fixed-time sliding mode control law is proposed by applying the developed sliding mode surface and adaptive technique. As a result, the convergence time of the closed-loop system is bounded and independent of the initial conditions. Simulation and experiments are presented to verify that the proposed scheme can effectively and rapidly achieve attitude stabilization while maintaining high control precision and robustness.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Voxel-Based Localization and Mapping for Multirobot System in GPS-Denied
           Environments

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      Authors: Hongming Shen;Qun Zong;Bailing Tian;Hanchen Lu;
      Pages: 10333 - 10342
      Abstract: Collaboration localization and mapping in GPS-denied environments is a challenging problem, due to the computing power and communication bandwidth constraints of onboard equipment. In this article, a voxel-based localization and mapping system is developed, which achieves real-time trajectory estimation for the multirobot system utilizing only onboard sensors, computing power, and communication module. The key idea of the voxel-based matching approach is to formulate the registration problem as a maximum a posteriori (MAP) problem and to simplify it to a nonlinear least-squares problem using Gauss approximation and principal component analysis (PCA). The voxel-based matching method significantly improves the computational efficiency and reduces the communication bandwidth of the localization and mapping system. The effectiveness of the proposed method is demonstrated through experiments in real-world environments for various scenarios.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Clutch Mechanical Leg Neural Network Adaptive Robust Control of Shift
           Process for Driving Robot With Clutch Transmission Torque Compensation

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      Authors: Gang Chen;Junhao Jiang;Liangmo Wang;Weigong Zhang;
      Pages: 10343 - 10353
      Abstract: In order to improve the motion accuracy and robustness of the clutch mechanical leg for driving robot (CMLDR), and to improve the shift performance of the driving robot vehicle (DRV) for the engagement operation of CMLDR, a neural network adaptive robust control method of shift process for CMLDR with clutch transmission torque compensation is proposed. First, the dynamics model of the driving robot is established considering an external interference force and dynamic modeling error of the mechanical leg. Second, the upper clutch controller including a two-parameter shift module, a switch controller, and a finite-time linear quadratic regulator of the clutch transmission torque is designed. Third, the estimator of clutch engagement torque through a Kalman filter in the process of shift is constructed. Then, the neural network adaptive robust (NNAR) controller of the mechanical leg is designed. Finally, the proof of stability analysis for NNAR controller is conducted. Experiment and simulation results show that the designed controller of the mechanical leg has a strong antiinterference ability. And the DRV accurately tracks the target speed after compensating for the transmission torque.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • A Metric for Assessing, Comparing, and Predicting the Performance of
           Autonomous RFID-Based Inventory Robots for Retail

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      Authors: Bernat Gastón;Víctor Casamayor-Pujol;Sergio López-Soriano;Rafael Pous;
      Pages: 10354 - 10362
      Abstract: Radio frequency identification (RFID) technology is being widely adopted by retailers due to its accuracy, versatility, and reduction of operational costs. Most commonly, RFID in retail is used for taking frequent and accurate inventories of items in the stores. Usually, RFID inventories use handheld RFID devices, which makes the task tedious, costly, and prone to human errors. More reliable, fully automatic alternatives exist, such as smart shelves, overhead RFID antennas, and RFID-equipped robots. Among them, robots seem to be the preferred choice by retailers with large stores. However, retailers need an objective way to compare the different options for inventory solutions and to calculate the return on investment of each of them before they make an investment decision. In this article, we present a metric for assessing, comparing, and predicting the performance of autonomous RFID-based robots in retail stores. The metric is based on a theoretical model of both the store and the robot, and predicts the performance of a given robot when inventorying a specific store. The metric also allows to compare the performance of different RFID robots in different stores. The metric has been developed using experimental data and has been validated in a real store.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Nonlinear Model Predictive Control of a Robotic Soft Esophagus

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      Authors: Dipankar Bhattacharya;Ryman Hashem;Leo K. Cheng;Weiliang Xu;
      Pages: 10363 - 10373
      Abstract: Strictures caused by esophageal cancer can narrow down the esophageal lumen, leading to dysphagia. Palliation of dysphagia has driven the development of a robotic soft esophagus (RoSE), which provides a novel in vitro platform for esophageal stent testing and food viscosity studies. In RoSE, peristaltic wave generation and control were done in an open-loop manner since the conduit lacked visibility and embedded sensing capability. Hence, in this work, RoSE version 2.0 (RoSEv2.0) is designed with embedded time of flight (TOF) and pressure sensors to measure conduit displacement and air pressure, respectively, for modeling and control. Model predictive control (MPC) of RoSEv2.0 is implemented to govern the peristalsis and air pressure profile autonomously. The implemented MPC used sparse identification of nonlinear dynamics with control (SINDYC) models to estimate the future states of ROSEv2.0. The dynamic models are discovered from the TOF and pressure sensor data. Peristalsis waves of speed 20 mm $cdot$ s$ ^{-1}$, wavelength 75 mm, and amplitudes 5, 7.5, and 10 mm were successfully generated by the MPC. Additionally, RoSEv2.0 with the MPC was employed to perform stent migration testing with various food boluses consistencies. The major contribution claimed in this article is the application of SINDYC-based MPC to solve the closed-loop control problem of RoSE for achieving desired peristaltic waves.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Designing and Modeling of Tightly Wrapped Twisted Artificial Muscles With
           Large Stroke and Low Hysteresis

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      Authors: Dong Zhou;Yingxiang Liu;Jie Deng;Weishan Chen;Jin Sun;Yuan Fu;
      Pages: 10374 - 10384
      Abstract: Soft actuator is the key component for soft robots to realize flexible motion. But the difficulty of sensing and control of soft actuators seriously restricts their application. Twisted artificial muscles (TAMs) made from together self-coiling of nylon 6,6 fiber and heating wire are potential to address this challenge due to their extremely high actuating stress and self-sensing ability. However, the together coiled twisted artificial muscles (TCTAMs) have a large self-sensing hysteresis because of the small heating area and the self-coiling process restricts their deformation stroke. Besides, the lack of accurate physical models also blocks the development of the TCTAMs. This article presents a new type of tightly wrapped twisted artificial muscles (TWTAMs) to improve the stroke and reduce the hysteresis. Compared with TCTAMs, the hysteresis of TWTAMs is reduced by 76% and the stroke is improved by 35%. Besides, a physical analytical model based on the self-sensing temperature is established and verified by experiments. This article not only provides a new type of TAMs with large stroke and low hysteresis, but also offers an accurate theoretical analysis model for the performance prediction of TWTAM.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • A Hybrid Calculation Method of Electromagnetic Vibration for Electrical
           Machines Considering High-Frequency Current Harmonics

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      Authors: Yang Lu;Jian Li;Kai Yang;
      Pages: 10385 - 10395
      Abstract: This article proposes a hybrid evaluation method of electromagnetic force and vibration for electrical machines considering high-frequency current harmonics caused by the inverter. First, the permeance and armature magnetomotive force (MMF) is calculated based on the virtual MMF and the slot matrix. Then, the air-gap flux density and electromagnetic force construction process under arbitrary current is thoroughly studied. The vibration transfer function is obtained by utilizing the modal analysis and the modal test. Finally, the vibration can be calculated according to the modal superposition method. By applying this method to an interior permanent magnet machine, it can significantly reduce the computation efforts compared with the multiphysics procedure due to the extensive use of the finite-element method. In addition, the accuracy of this method is validated by conducting an experimental study.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Restraining the Backward Motion of a Piezoelectric Stick-Slip Actuator
           With a Passive Damping Foot

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      Authors: Xinqi Tian;Weishan Chen;Binrui Zhang;Yingxiang Liu;
      Pages: 10396 - 10406
      Abstract: The backward motion is an intrinsic feature of the conventional piezoelectric stick-slip actuator (PSSA), limiting the output speed and applications. Various methods have been proposed for restraining the backward motion. Each method has its pros and cons for the practical application of driving a precision motion stage. A novel method for restraining the backward motion is proposed in this article, in which a passive damping foot is utilized to hold the runner when the active driving foot slips on the runner. An actuator is developed based on this mechanism. The structural dimensions of the actuator are determined with an analytic model and a finite element model. A prototype of the proposed actuator is fabricated and tested by experiments. The experiments validate the operating principle of the actuator for restraining the backward motion, which is eliminated (the backward ratio is less than 1%) when the passive damping foot has an appropriate clamping force. The proposed method is very valuable for designing a PSSA with no backward motion, and it can broaden the applications for precision manipulations.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Development of a Linear Piezoelectric Microactuator Inspired by the
           Hollowing Art

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      Authors: Jing Li;Yingxiang Liu;Jie Deng;Shijing Zhang;Weishan Chen;
      Pages: 10407 - 10416
      Abstract: Microactuators have been playing crucial roles in micromachine technologies because of their small sizes and light weights. The piezoelectric actuation is one of the most important driving methods to perform the motion output with miniature structures. The rotary piezoelectric microactuators are relatively mature, whereas the linear ones need to be further developed. Inspired by the hollowing art, a novel linear piezoelectric microactuator with miniature dimensions of 7.4 mm × 7.4 mm × 10 mm is proposed, which is designed to be an integrated hollow structure without a guide rail and can achieve bidirectional standing-wave drive. The bidirectional motions are achieved by the same first-order bending vibrations of two pairs of thin-walled beams, respectively, which are conducive to the consistency of the forward and backward motions indicate that the maximum velocity, resolution, and maximum thrust force achieved in the forward motion are 19.06 mm/s, 0.3 μm, and 17.45 mN, respectively, whereas those in the backward motion are 16.92 mm/s, 0.45 μm, and 15.28 mN, respectively. The design inspired by the hollowing art has the potential to be an effective and alternative solution for the development of linear piezoelectric microactuators.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Design of a Long Stroke Nanopositioning Stage With Self-Damping Actuator
           and Flexure Guide

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      Authors: Chi Zhang;Xiaolu Huang;Miao Yang;Silu Chen;Guilin Yang;
      Pages: 10417 - 10427
      Abstract: Long stroke nanopositioning stages with high natural frequency and compact size are demanded in precision engineering. However, in previous researches, the natural frequency of the long stroke nanopositioning stage is normally below 50 Hz because the actuated force, moving mass, stiffness, motion range, and damping ratio are not considered simultaneously and optimized thereafter. To solve this problem, a long stroke nanopositioning stage driven by the self-damping moving magnet actuator (SMMA) and supported by the flexure guide is integrated and designed in this article. The SMMA consists of two identical tooth-slot structure stators and one moving magnet which is embedded inside the flexure guide. Copper plates that functioned as eddy-current dampers are attached on the tooth surfaces to suppress the resonance peak at the natural frequency. An integrated dynamics model that consists of force, damping coefficient, and stiffness is established. The dimensional parameters of the proposed positioning stage are optimized to improve the system performances based on the developed model. Experimental results show that the natural frequency of the positioning stage reaches up to 71 Hz. The stage can achieve 20 nm positioning resolution within a motion range of $pm$5 mm, and the root mean square tracking errors for 1 Hz sinusoidal and triangular commands are below 0.1% of the trajectory amplitudes.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Design Criterion for Dual-Modular Permanent Magnet Linear Synchronous
           Motor With Long Stroke and High Flexibility

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      Authors: Jing Li;Xuzhen Huang;Bo Zhou;Yan Song Liu;Qian Huang;
      Pages: 10428 - 10436
      Abstract: Permanent magnet linear synchronous motor (PMLSM) has a wide application prospect in transmission systems of automatic production, logistics, and other fields. However, the existing PMLSM has the problems of poor flexibility and large thrust fluctuation adapted to load and stroke variation. In order to solve this problem, a dual-modular PMLSM is proposed. The motor can be flexibly configured with multiple-unit-primary and multiple-unit-secondary, and achieve low thrust fluctuation. The matching criterion of unit-primary (UP) and secondary is established to reveal the relationship between the slot/pole combination and the winding utilization. The rules of the average thrust varying with the different UP and unit-secondary (US) lengths are illustrated. Then, the matching criterion of different UP is proposed, and the optimization method of the spacing between UP (S1) is obtained by establishing the end force model. The design standard of the optimal S1 is obtained by combining the two factors of minimum detent force and maximum thrust. The results are verified by the simulation and experiments on a 3UP-96US dual-modular PMLSM circular transmission line system and its prototype.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Recurrent Model Predictive Control: Learning an Explicit Recurrent
           Controller for Nonlinear Systems

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      Authors: Zhengyu Liu;Jingliang Duan;Wenxuan Wang;Shengbo Eben Li;Yuming Yin;Ziyu Lin;Bo Cheng;
      Pages: 10437 - 10446
      Abstract: This article proposes an offline control algorithm, called recurrent model predictive control, to solve large-scale nonlinear finite-horizon optimal control problems. It can be regarded as an explicit solver of traditional model predictive control (MPC) algorithms, which can adaptively select appropriate model prediction horizon according to current computing resources, so as to improve the policy performance. Our algorithm employs a recurrent function to approximate the optimal policy, which maps the system states and reference values directly to the control inputs. The output of the learned policy network after $N$ recurrent cycles corresponds to the nearly optimal solution of $N$-step MPC. A policy optimization objective is designed by decomposing the MPC cost function according to the Bellman’s principle of optimality. The optimal recurrent policy can be obtained by directly minimizing the designed objective function, which is applicable for general nonlinear and noninput-affine systems. Both simulation-based and real-robot path-tracking tasks are utilized to demonstrate the effectiveness of the proposed method.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Adaptive Control of a Mechatronic System Using Constrained Residual
           Reinforcement Learning

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      Authors: Tom Staessens;Tom Lefebvre;Guillaume Crevecoeur;
      Pages: 10447 - 10456
      Abstract: In this article, we propose a simple, practical, and intuitive approach to improve the performance of a conventional controller in uncertain environments using deep reinforcement learning while maintaining safe operation. Our approach is motivated by the observation that conventional controllers in industrial motion control value robustness over adaptivity to deal with different operating conditions and are suboptimal as a consequence. Reinforcement learning, on the other hand, can optimize a control signal directly from input–output data and thus adapts to operational conditions but lacks safety guarantees, impeding its use in industrial environments. To realize adaptive control using reinforcement learning in such conditions, we follow a residual learning methodology, where a reinforcement learning algorithm learns corrective adaptations to a base controller’s output to increase optimality. We investigate how constraining the residual agent’s actions enables to leverage the base controller’s robustness to guarantee safe operation. We detail the algorithmic design and propose to constrain the residual actions relative to the base controller to increase the method’s robustness. Building on Lyapunov stability theory, we prove stability for a broad class of mechatronic closed-loop systems. We validate our method experimentally on a slider crank setup and investigate how the constraints affect the safety during learning and optimality after convergence.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Adaptive Burst Mode of LCC Resonant Converters With
           Reduced Audible Noise

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      Authors: Jun Zhao;Liang Wu;Guozhu Chen;
      Pages: 10457 - 10466
      Abstract: At light load, the efficiency of LCC resonant converters decreases dramatically. The burst mode is a good choice to improve it. However, the burst frequency is changing at different loads, and the audible noise is unavoidable when the burst frequency enters into the audible range (20 Hz–20 kHz). In this article, according to the state trajectories of two steady-state modes, four different burst modes for LCC resonant converters based on trajectory control are proposed, which cover different power ranges. Then, the proposed state trajectories of four burst modes are described, and the width of burst on pulses is derived accordingly. By switching to different burst modes under different loads, the proposed adaptive burst mode can cover a much wider load range free of audible noise. Finally, to verify the proposed adaptive burst mode, an LCC converter prototype is constructed, which shows that the burst frequency keeps above audible range from 0.2% to 20% full load with efficiency improved.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • A Ka-Band High-Power Switchable Filtering Power Combiner MMIC in 100-nm
           GaN-on-Si

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      Authors: Guangxu Shen;Haoshen Zhu;Dingyuan Zeng;Quan Xue;Wenquan Che;
      Pages: 10467 - 10477
      Abstract: This article presents a Ka-band switchable filtering power combiner monolithic microwave integrated circuit (MMIC), which unifies the functionalities of the switch, bandpass filter, and power combiner. For effective integration, a codesign approach is proposed by sharing the switchable resonant units and coupling matrix based impedance matching technique. Moreover, this approach offers great design freedom to realize arbitrary bandwidth and power ratios. For good return loss, the input external quality factor (Qe) is ensured as half of output Qe based on even-mode analysis. By analyzing the odd-mode circuit, the complex isolation element is introduced to improve the isolation between input ports. For demonstration, one prototype is implemented using a 100-nm GaN-on-Si process. Over 18-dB return loss, 1.7-dB minimum insertion loss (excluding 3-dB power ratio), >22 dB input–input isolation, and over 47-dB off-state isolation can be observed throughout 24–32 GHz. Besides, the proposed MMIC shows good linearity with a measured IP1dB of over 30 dBm within the passband, while the die size is 0.81 mm2.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Distributed Control of Parallel DC–DC Converters Under FDI Attacks
           on Actuators

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      Authors: Mahdieh S. Sadabadi;Nenad Mijatovic;Jean-François Trégouët;Tomislav Dragičević;
      Pages: 10478 - 10488
      Abstract: The parallel connection of dc–dc converters requires the development of an appropriate control strategy that regulates load voltage and shares current among participating converters. This article proposes a resilient and robust cooperative distributed control approach that simultaneously ensures voltage regulation and balanced current sharing in parallel dc–dc converters in the presence of false data injection attacks on control input channels. Based on analytical tools from network control and Lyapunov stability theory, concise stability certificates are derived. The proposed cooperative distributed control strategy guarantees resilience against unknown bounded attacks on the actuators of dc–dc converters and the robustness to uncertainties in load parameters and the physical parameters of converters. Furthermore, the control design for each converter does not require any knowledge about the number of participating converters. The detailed simulation and experimental results verify the satisfactory performance of the proposed method in voltage regulation and balanced current sharing in parallel converters, as well as resilience to bounded false data injection attacks.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Sliding Mode Dual-Channel Disturbance Rejection Attitude Control for a
           Quadrotor

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      Authors: Jiaxin Xiong;Jian Pan;Guangyi Chen;Xiao Zhang;Feng Ding;
      Pages: 10489 - 10499
      Abstract: In this article, a sliding mode dual-channel disturbance rejection control based on an extended state observer is proposed for the attitude control of a quadrotor under unknown disturbances. There exist an inner disturbance rejection channel (IDRC) and an outer disturbance rejection channel (ODRC) in this control scheme. In the IDRC, a low-frequency disturbance compensator is proposed to obtain the disturbance compensation value and to compensate the low-frequency component of the lumped disturbance. In the ODRC, a novel sliding mode controller with a variable-gain switching term and a constant-gain switching term is designed, and the switching terms are used to compensate the virtual disturbance estimation error and the high-frequency component of the lumped disturbance. The low-frequency and high-frequency components of the lumped disturbance can be estimated and the influence of the virtual disturbance estimation error is reduced by using the proposed control scheme. The stability of the system is proved by using the Lyapunov theory. Finally, the effectiveness of the proposed scheme is tested by numerical simulations and platform experiments.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Approximation-Free Robust Synchronization Control for
           Dual-Linear-Motors-Driven Systems With Uncertainties and Disturbances

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      Authors: Zhitai Liu;Weiyang Lin;Xinghu Yu;Juan J. Rodríguez-Andina;Huijun Gao;
      Pages: 10500 - 10509
      Abstract: This article addresses the synchronization control problem for dual-linear-motors-driven systems with model uncertainties and disturbances. An approximation-free robust synchronization control scheme based on cross-coupled control (CCC) frame is proposed to achieve high-precision tracking and synchronization performance, along with excellent uncertainties and disturbances rejection ability. More specifically, the CCC frame is designed to handle the asynchronous motion of two parallel motors. The main advantage is that the proposed method does not require the explicit system model, and any approximations utilized to handle the model uncertainties, such as estimation, identification, and online learning, are not required. Therefore, the computational burden and complexity of the controller are significantly reduced. Considering the importance of the transient and steady-state response, the concept and technology of prescribed performance are adopted to guarantee the control effect and state constraints. In addition, none of the high-order derivatives of desired trajectory, difficult to obtain directly in many applications, are used in the proposed controller. Furthermore, the stability and convergence performance of the closed-loop system are rigorously demonstrated. Finally, comparative experiments show the effectiveness of this study via a dual-driven H-type gantry.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Neural Network-Based Tracking Control of Uncertain Robotic Systems:
           Predefined-Time Nonsingular Terminal Sliding-Mode Approach

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      Authors: Yizhuo Sun;Yabin Gao;Yue Zhao;Zhuang Liu;Jiahui Wang;Jiyuan Kuang;Fei Yan;Jianxing Liu;
      Pages: 10510 - 10520
      Abstract: This article investigates the predefined time trajectory tracking control of uncertain nonlinear robotic systems. A radial basis function neural network (RBFNN) is used to estimate uncertainties in the robotic system dynamics. To avoid the singularity of terminal sliding-mode control (TSMC), a modified sliding variable is adopted. In order to realize that the tracking errors can converge to a small neighborhood of the origin in predefined time, within which the maximum convergence time can be adjusted by explicit parameters in advance, a nonsingular TSMC based on the RBFNN is proposed. Experiments on a ROKAE platform demonstrate the effectiveness and advantage of the proposed control method.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Distributed Localization of Multiagent Systems With Imperfect Channels
           Based on Iterative Learning

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      Authors: Yunkai Lv;Hao Zhang;Chao Huang;Zhuping Wang;
      Pages: 10521 - 10529
      Abstract: The real-time localization problem for a class of multiagent systems with imperfect channels under directed graphs is investigated in this article. A successive distributed localization estimation algorithm based on iterative learning is proposed to solve the localization problem of the agent with bounded communication delays. The barycentric coordinates are used to represent the relative position between agents. An estimator is proposed to inspect whether the received data packet is the latest through the iteration stamp on the packet. Meanwhile, an intermittent distributed localization algorithm is devised to handle with the random data loss of agents in real-time localization problem. The relationship between the convergence rate and the probability of the data loss is given in the sense of mathematical expectations. Both numerical simulation and Qbot-2e robot experiment are provided to verify the effectiveness and the feasibility of the aforementioned methods.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Two-Terminal Suspension Adaptive Control With Synchronous Compensation for
           Maglev Wind Turbine Yaw System

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      Authors: Xiaoguang Chu;
      Pages: 10530 - 10540
      Abstract: The article proposes an adaptive robust controller with synchronization compensation for the Maglev wind turbine yaw system to achieve stable nacelle suspension and pitching suppression. First, two-degree-of-freedom suspension model is constructed with consideration of magnetic coupling and pitching interference, and then deduces a two-terminal suspension control model based on the inverse system. Second, a nominal suspension controller is designed based on the composite error; and then an adaptive synchronization controller is proposed to adjust coupling parameters based on reconstructed synchronous function; an adaptive tracking controller is used to online update dominant control input parameters. The robust controller is to compensate for the influence of the approximation errors during the parameters convergence process. It is proved that the proposed strategy can guarantee the globally uniformly ultimately bounded of all signals, and suspension tracking error and synchronization error can converge to the desired smaller neighborhood of zero. Finally, simulation and experimental results show that the system with the proposed strategy has the faster dynamic response, smaller steady error and synchronization error, and stronger robustness than other two strategies.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Boundary-Based Predictive Controller and Its Application to Control of
           Dissolved Oxygen Concentration in Activated Sludge Bioreactor

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      Authors: Krzysztof Stebel;Jakub Pospiech;Witold Nocon;Jacek Czeczot;Piotr Skupin;
      Pages: 10541 - 10551
      Abstract: This article presents the concept of boundary-based predictive controller (BBPC) as an effective tool to control industrial processes with on--off actuator, for which the control goal is defined to keep the process output within the desired range. An example use of BBPC is shown in application to control of dissolved oxygen (DO) concentration in the laboratory activated sludge setup with biological reactor. It is suggested how to identify dynamical parameters of the proposed DO concentration model and how to provide adaptability required to ensure desired control performance in the presence of significant changes of process load disturbance. Practical implementation in programmable logic controller in the form of a general purpose library function block is also presented. Experimental comparison with conventional on–off controller shows robustness and superiority of the proposed BBPC.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Generalized Transient-Extracting Transform and Its Accurate Signal
           Reconstruction

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      Authors: Wenjie Bao;Yue Hu;Fucai Li;
      Pages: 10552 - 10563
      Abstract: Traditional time–frequency analysis (TFA) methods can effectively obtain instantaneous frequency (IF) features of nonstationary signals by constructing the signal model in the time domain. However, they fail to deal with the transient signal because the IF of the transient signal is discontinuous in the time domain and is a multivalued function with respect to time. Thus, in this article, we introduce a new TFA method, termed generalized transient-extracting transform (GTET), to obtain sharper time–frequency representation (TFR) of the transient signal by constructing frequency-domain model. First, we propose a new computational framework for group delay (GD). By deriving the general explicit formula for the Nth-order GD, the programming implementation of any order GD can be achieved. Next, the concentrated TFR of GTET can be generated by extracting the energy from the generalized GD estimation. Finally, the signal reconstruction of GTET is derived from a new perspective. It overcomes the difficulty that the reconstruction method of transient-extracting transform cannot be generalized to high-order algorithms. The analysis result of the simulated signal with high-order GD shows that GTET has better performance than other TFA methods. Experimental results demonstrate that GTET can be used to analyze practical transient signals.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • A Self-Reproduction Hyperchaotic Map With Compound Lattice Dynamics

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      Authors: Yongxin Li;Chunbiao Li;Sen Zhang;Guanrong Chen;Zhigang Zeng;
      Pages: 10564 - 10572
      Abstract: In this article, sinusoidal functions are introduced to a discrete map for hyperchaos generation and attractor self-reproduction. The constructed map shares a unique structure with controllable symmetry and conditional symmetry, which exhibits compound lattice dynamics, including 1-D and 2-D attractor growth. The direction of attractor growth can be controlled under polarity balance. STM32-based circuit realization verifies the results with numerical simulation and theoretical analysis. A pseudorandom number generator is built finally based on the newly proposed hyperchaotic map proving the high performance in application.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Prior Knowledge-Augmented Self-Supervised Feature Learning for Few-Shot
           Intelligent Fault Diagnosis of Machines

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      Authors: Tianci Zhang;Jinglong Chen;Shuilong He;Zitong Zhou;
      Pages: 10573 - 10584
      Abstract: Data-driven intelligent diagnosis models expect to mine the health information of machines from massive monitoring data. However, the size of faulty monitoring data collected in engineering scenarios is limited, which leads to few-shot fault diagnosis as a valuable research point. Fortunately, it is possible to reduce the required amount of training data by integrating prior diagnosis knowledge into diagnosis models. Inspired by this, we present a prior knowledge-augmented self-supervised feature learning framework for few-shot fault diagnosis. In the framework, 24 signal feature indicators are built to form prior features set based on existing diagnosis knowledge. Besides, a convolutional autoencoder is used to mine the general features, which are considered to potentially contain fault information that prior features do not possess. We design a self-supervised learning scheme for training the diagnosis model, which enables the model to learn both prior and general features served as proxy labels. As a result, the model is expected to mine richer features from limited monitoring data. The effectiveness of the proposed framework is verified using two mechanical fault simulation experiments. From the angle of prior diagnosis knowledge, the proposed framework provides a new perspective to the problem of few-shot intelligent diagnosis of machines.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Multisource Partial Transfer Network for Machinery Fault Diagnostics

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      Authors: Yaoxiang Yu;Liang Guo;Yongwen Tan;Hongli Gao;Jiangquan Zhang;
      Pages: 10585 - 10594
      Abstract: As for some machineries in real industrial applications, it is difficult to obtain massive labeled data. Therefore, transfer learning is introduced to apply the knowledge learned from labeled datasets on the unlabeled data for the fault diagnosis of machineries. However, there are the following three challenges in real applications. First, the label space of unlabeled datasets may be unknown. Second, the labeled machinery datasets often only include a part of fault types. Third, it is difficult to apply some ideal datasets to real data. For solving such problems, a new transfer learning model namely multisource partial transfer network is proposed. First, this model is constructed by four modules, including a common module and three domain-specific modules. The common module extracts common features while the domain-specific modules are responsible for fault diagnosis and domain adaptation through capturing domain-specific features. During training, the specific modules are trained through their corresponding source domain, respectively. Then, for reducing negative effects from outlier classes, two kinds of class-level weight mechanisms are designed in optimization objectives. The distance between target domain and source domain is measured as a standard to assist the target domain to learn knowledge selectively. Afterwards, particle swarm optimization is applied to search for initial parameters for the proposed model. Finally, its performance is verified through six datasets.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Dynamic Graph-Based Feature Learning With Few Edges Considering Noisy
           Samples for Rotating Machinery Fault Diagnosis

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      Authors: Kaibo Zhou;Chaoying Yang;Jie Liu;Qi Xu;
      Pages: 10595 - 10604
      Abstract: Due to its ability to learn the relationship among nodes from graph data, the graph convolution network (GCN) has received extensive attention. In the machine fault diagnosis field, it needs to construct input graphs reflecting features and relationships of the monitoring signals. Thus, the quality of the input graph affects the diagnostic performance. But it still has two limitations: 1) the constructed input graph usually has redundant edges, consuming excessive computational costs; 2) the constructed input graph cannot reflect the relationship between the noisy signals well. In order to overcome them, a dynamic graph-based feature learning with few edges considering noisy samples is proposed for rotating machinery fault diagnosis in this article. Noisy vibration signals are converted into one spectrum feature-based static graph, where redundant edges are simplified by the distance metric function. Edge connections of the input static graph are updated according to the relationship among high-level features extracted by the GCN. Based on this, dynamic input graphs are reconstructed as new graph representations for noisy samples. To verify the effectiveness of the proposed method, validation experiments were conducted on practical platforms, and results show that the dynamic input graph with few edges can effectively improve the diagnostic performance under different SNRs.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Influence of Voltage Harmonics on Partial Discharge Diagnostics in
           Electric Motors Fed by Variable-Frequency Drives

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      Authors: Waqar Hassan;Farhan Mahmood;Amedeo Andreotti;Mario Pagano;Farooq Ahmad;
      Pages: 10605 - 10614
      Abstract: Typically, in partial discharges (PD) diagnostics tests carried out in a laboratory, harmonic content in a voltage waveform is ignored. However, during the operation of variable-frequency drives (VFD)-fed electric motors, the distorted voltage waveform is produced due to the addition of harmonics components in the sinusoidal voltage waveform. The distortion level increases when the VFD is operated at a lower speed ratio. The additional spectral components in the applied voltage waveform can have a significant impact on the PD behavior in the insulation of the electric motor. Therefore, during online PD monitoring, overlooking the harmonic regime in the applied voltage may lead to a false interpretation of PD data. This article investigates the influence of voltage harmonics distortion produced during the variable-speed operation of VFD on PD characteristics. For this purpose, online PD measurements have been carried out by performing a series of experiments on eight VFD-fed motors under variable operating conditions. The PD severity at different harmonic compositions is experimentally investigated by determining various PD characteristic parameters including PD inception voltage, accumulated apparent charge, average discharge current, discharge power, and quadratic rate. Also, two terms Gaussian models have been mathematically developed using 288 data samples to quantify the variations in PD characteristic parameters against distortion parameters. The article proposes a framework for properly evaluating harmonics impact in PD for electric motors and correctly estimating stator insulation degradation.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Health Indicator Construction Method of Bearings Based on Wasserstein
           Dual-Domain Adversarial Networks Under Normal Data Only

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      Authors: Jie Li;Yanyang Zi;Yu Wang;Ying Yang;
      Pages: 10615 - 10624
      Abstract: Rolling bearings are the most critical parts of rotating machinery and their damage is the leading cause of system failures. To ensure the reliability of the system, it demands to construct a health indicator (HI) to assess the state of degradation. However, existing HI construction methods (HICMs) have two limitations. First, the integration of well-designed features relies heavily on the experience of domain expert knowledge. Second, the construction of intelligent HI relies too much on life-cycle data. To cope with these limitations, this article proposed an HICM–Wasserstein dual-domain adversarial networks (WD-DAN), namely HICM-WD-DAN, which can extract generalized features with only normal data during the training. The dual-domain restriction of regularization promotes the generated signals approach to normal samples, making the constructed HI more robust and accurate. Moreover, to balance the weights of dual-domain parts automatically, an independent weighting structure is introduced. Finally, considering the actual degradation state of the system, the modified monotonicity and trendability indexes are proposed to evaluate the performance of HI. The effectiveness of HICM-WD-DAN is verified by bearings’ life-cycle data, and the results show that the constructed HI can represent the irreversible degradation process of bearings accurately and monotonously.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Quasi-Distributed Vibration Sensing System for Transformers Using a
           Phase-Sensitive OFDR

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      Authors: Wei-Qi Qin;Guo-Ming Ma;Meng Zhang;Yuan Wang;Jun Jiang;Hongyang Zhou;Xilin Wang;Chao Yan;
      Pages: 10625 - 10633
      Abstract: A quasi-distributed vibration sensing system based on a phase-sensitive optical frequency-domain reflectometer is proposed for monitoring the vibration of power transformer oil tanks. Compared with traditional accelerometers, the proposed system has high electromagnetic interference immunity. In this article, the principles of localization and vibration sensing are introduced. Then, the system layout and the vibration signal demodulation process are explained in detail. Next, the vibration sensing performance of the system is calibrated experimentally. Finally, vibration monitoring tests are carried out in a laboratory environment and on-site to verify the vibration detection capability of the system. The proposed system can be used to measure the time domain, frequency domain, and spatial distribution of oil tank vibration, which can be used for the online monitoring of the mechanical state of power transformers.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • A Novel Method for Measuring, Collimating, and Maintaining the Spatial
           Pose of Terminal Beam in Laser Processing System Based on 3D and 2D Hybrid
           Vision

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      Authors: Xiaodong Wang;Bin Liu;Xuesong Mei;Xintian Wang;Renhan Lian;
      Pages: 10634 - 10643
      Abstract: The terminal beam collimation problem of laser processing systems has traditionally been a headache. The deflection of the terminal beam seriously affects the processing accuracy and success. In this article, A novel method for measuring, collimating, and maintaining the spatial pose of the terminal beam in a five-axis laser processing system based on 3-D and 2-D hybrid vision is proposed. The beam pose in the working space of the laser processing system is measured by using a 3D scanner and an alignment sensor. The functional relationship between the galvanometer coordinates and the deflection angles of the terminal beam is established. The coordinates corresponding to the minimum deflection angle are solved to collimate the beam. Moreover, a camera is used to monitor the laser spot and re-collimate the deflected beam. The experimental results show that the method proposed in this article can effectively measure the deflection angle of the terminal beam, collimate the terminal beam and monitor the spot position of the terminal beam. The method can effectively improve the processing accuracy when applied to the laser processing system and has excellent potential application value.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Absolute Inductive Angular Displacement Sensor for Position Detection of
           YRT Turntable Bearing

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      Authors: Yangyang Wang;Yi Qin;Xihou Chen;Qifu Tang;Tianheng Zhang;Liang Wu;
      Pages: 10644 - 10655
      Abstract: This article proposes an absolute-type inductive angle sensor for detecting the position of the YRT turntable bearing. The sensor comprises a multispeed incremental measuring unit and a single-speed absolute measuring unit sharing the same stator, rotor, and excitation circuit. The stator is composed of a ferromagnetic gear groove, two groups of excitation coils, and one group of induction coils arranged according to certain rules. The end cover of the YRT turntable bearing is machined as rotor and it rotated eccentrically relative to the rotation of the stator. A bridge circuit is used to acquire and process the sensor signal from the single-speed measuring unit. Compared with the traditional dual-channel absolute measurement, the proposed measurement method avoids the effects of different magnetic circuit disturbances on signal quality and measurement accuracy, and has more advantages in the volume and weight of the sensor. The structure and working principles of the sensor are presented in detail, the feasibility of sensing scheme is verified via simulation, and a sensor prototype is designed for the final experiment. Experimental results show that the accuracy of the sensor prototype is –0.06758° to 0.1203° before compensation and –0.001139° to 0.0015° after compensation in the range of [0°, 360°], respectively.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Low-Frequency Wireless Power Transfer Via Rotating Permanent Magnets

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      Authors: Yue Wu;Huan Yuan;Renjie Zhang;Aijun Yang;Xiaohua Wang;Mingzhe Rong;
      Pages: 10656 - 10665
      Abstract: The surging applications of low-power sensors and portable electronic devices require a safe, convenient and low-cost charging method which draws interests of the wireless power transfer research field. Conventional WPT techniques using resonant coupling structures are limited by complexity, safety concerns and hardware costs. Electromechanical wireless power transfer (EWPT) techniques provide a low-cost, easy-to-control and safe wireless charging method via moving magnets; but transmission failures may occur due to the position and orientation misalignments of loads from optimum conditions. This article proposes an EWPT system that is able to charge loads at different tilt angles via a low-frequency rotating magnetic field and a permanent magnet rotor. The magnetic field has a uniform distribution in a space volume over 125 000 mm3. A custom permanent magnet rotor embedded with six identical cylindrical magnets and an induction coil is employed to capture transmitted power. Theoretical analyses and experimental results are presented to prove the feasibility and output capability of the proposed system. The peak output power achieves 130 mW under a magnetic field strength around 1 mT and the system output maintains stable for loads at different tilt angles. Such EWPT method can be applied as a stable power supply for free-positioned and free-oriented sensors or other low-power devices in an enclosed or semienclosed area.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Bringing the Lab to the Fab: Robot-Based Inline Measurement System for
           Precise 3-D Surface Inspection in Vibrational Environments

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      Authors: Daniel Wertjanz;Ernst Csencsics;Thomas Kern;Georg Schitter;
      Pages: 10666 - 10673
      Abstract: This article presents the integrated design of a robot-based inline measurement system for precise 3-D surface inspection on free-formed objects. The measurement system comprises a MAGLEV measurement platform that is mounted to an industrial robot and enables the out-of-plane tracking of an arbitrarily oriented sample surface. This establishes lab-like conditions for the integrated optical 3-D measurement tool directly in a vibrational environment. Using a proportional-integral-derivative control architecture with a tracking control bandwidth of 600 Hz, the effects of a vibration signal with 15.5 $mu$m rms can be reduced to disturbances with 236 nm rms. The orientation-independent measurement performance is demonstrated by imaging a calibration standard with 20 $mu$m pitch in various robot poses. Experiments show that the system is capable of reducing the axial measurement uncertainty by a factor of 12, enabling robot-based 3-D measurements with submicrometer resolution on freeform surfaces in a vibrational environment.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Underground Metal Pipeline Localization Using Low-Cost Wireless Magnetic
           Sensors Mounted on an Excavator

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      Authors: Jeonghee Kim;Youngjib Ham;Hangue Park;
      Pages: 10674 - 10683
      Abstract: To minimize the excavation damage of underground pipelines, in this article, we propose to provide real-time feedback to operators by monitoring the distance information from the underground pipeline. Despite multiple efforts to locate underground ferromagnetic pipelines using the magnetic anomaly detection, it has not been implemented in real-time excavation operations due to low signal-to-noise ratios, unknown external magnetic interference (EMI), and high computational power. To address these limitations, we propose an approach to locating a custom-designed wireless sensor system on the excavator bucket to increase accuracy of real-time distance estimation with efficient EMI cancelation. We present the system using a 14:1 lab-scaled excavator and six sizes of ferromagnetic pipes. To create a distance estimation model of each pipe, we measure the magnetic anomaly caused by ferromagnetic pipes from eight distances (from 5 to 75 mm, spaced 10 mm apart). The wireless system with the localization algorithm successfully estimates the distance between the sensor and the pipe with a less than 4.38 ± 1.62 mm error overall. This pilot study shows that the proposed system with the localization algorithm is able to accurately locate pipes. This will lay the foundation for providing accurate spatial information, and ultimately prevent critical excavation/drilling damage at construction sites.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Voltage Distortion Influence on Flicker Severity Measurement by AMI Energy
           Meters

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      Authors: Grzegorz Wiczyński;Piotr Kuwałek;
      Pages: 10684 - 10693
      Abstract: This article addresses the problem of proper flicker severity assessment by smart energy meters. Flicker severity occurs for a typical voltage “clipped cosine” distortion caused by operation of power electronic devices in the power grid. The voltage distortion caused only by higher harmonics does not cause voltage fluctuations, and therefore does not cause flicker. This article presents the research results for some models of advanced metering infrastructure (AMI) smart meters, for which irregularities are observed in the voltage variation severity assessment if the typical voltage distortion occurs in the power grid. Possible mistakes in implementation of flickermeter signal chain as defined by International Electrotechnical Commission (IEC) in smart meters that influence the measurement results have been explained. The analysis of the influence of typical voltage distortion on the indicator $P_{st}$ measurement has been carried out analytically and in numerical simulation studies using the modeled flickermeter signal chain.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • A Modular Approximation Methodology for Efficient Fixed-Point Hardware
           Implementation of the Sigmoid Function

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      Authors: Zhe Pan;Zonghua Gu;Xiaohong Jiang;Guoquan Zhu;De Ma;
      Pages: 10694 - 10703
      Abstract: The sigmoid function is a widely used nonlinear activation function in neural networks. In this article, we present a modular approximation methodology for efficient fixed-point hardware implementation of the sigmoid function. Our design consists of three modules: piecewise linear (PWL) approximation as the initial solution, Taylor series approximation of the exponential function, and Newton–Raphson method-based approximation as the final solution. Its modularity enables the designer to flexibly choose the most appropriate approximation method for each module separately. Performance evaluation results indicate that our work strikes an appropriate balance among the objectives of approximation accuracy, hardware resource utilization, and performance.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Personalized Driver Braking Behavior Modeling in the Car-Following
           Scenario: An Importance-Weight-Based Transfer Learning Approach

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      Authors: Zirui Li;Jianwei Gong;Chao Lu;Jinghang Li;
      Pages: 10704 - 10714
      Abstract: Accurately recognizing braking intensity levels (BIL) of drivers is important for guaranteeing the safety and avoiding traffic accidents in intelligent transportation systems. In this article, an instance-level transfer learning framework is proposed to recognize BIL for a new driver with insufficient driving data by combining the Gaussian mixture model (GMM) and the importance-weighted least-squares probabilistic classifier (IWLSPC). By considering the statistic distribution, GMM is applied to cluster the data of braking behaviors into three levels with different intensities. With the density ratio calculated by unconstrained least-squares importance fitting, the least-squares probabilistic classifier is modified as IWLSPC to transfer the knowledge from one driver to another and recognize BIL for a new driver with insufficient driving data. Comparative experiments with nontransfer methods indicate that the proposed framework obtains a higher accuracy in recognizing BIL in the car-following scenario, especially when sufficient data are not available.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Improved MPPT System Based on FTSMC for Thermoelectric Generator Array
           Under Dynamic Temperature and Impedance

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      Authors: Ning Wang;Jian-Nan Zhang;Hao Ni;Hong-Zhi Jia;Can Ding;
      Pages: 10715 - 10723
      Abstract: The thermoelectric generator (TEG) is typically used as a clean power supply to harvest waste heat energy in applications involving a large thermal gradient, such as industrial heat removal and power electronic equipment systems. However, it is often difficult to achieve the optimal output power in the loop of the array system of the TEG owing to different output loads. This article proposes an improved fast terminal sliding-mode variable-structure control algorithm (FTSMC) to maximize power point tracking. The variable-structure sliding-mode control function used in the nonlinear sliding-mode surface of the algorithm allows us to obtain the characteristics of global stability that can enable it to converge to the sliding-mode surface at any position to reduce chatter. Digital modeling and simulation as well as experimental developmental field programmable gate array platforms were built to verify the effectiveness of the proposed FTSMC. It can attain the nonlinear sliding mode more quickly than the traditional sliding-mode algorithm. The results of experiments show that it can reach a tracking response speed of 0.08 s and a maximum conversion efficiency of 99.91%. The work here provides a new way for the efficient use of the TEG array for waste heat recovery.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • Online Unified Solution for Selective Harmonic Elimination Based on
           Stochastic Configuration Network and Levenberg–Marquardt Algorithm

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      Authors: Jun Hao;Guoshan Zhang;Kehu Yang;Mingzhe Wu;Yuqing Zheng;Wei Hu;
      Pages: 10724 - 10734
      Abstract: In this article, an online unified solution based on stochastic configuration network (SCN) and Levenberg– Marquardt (LM) algorithm is proposed to generate optimal switching angles for selective harmonic elimination (SHE) in both the symmetric and asymmetric cascaded H-bridge (CHB) multilevel inverters (MLIs). Different from the traditional neural network framework for SHE, this unified solution uses SCN to only generate initial values of the switching angles online, which significantly reduce the precision demand on training SCN and avoids the local optima problem of gradient descent algorithm. After obtaining the initial values from SCN online, the LM algorithm can be used to rapidly solve the exact switching angles for SHE, which guarantees the solving efficiency and precision of the final solutions. Moreover, the stability of the proposed method is proved via Newton-like convergence theory. Compared with intelligent search algorithms and look-up table method, the proposed solution can not only online generate optimal theoretical switching angles but with much fewer data storage space. Experimental results of both symmetric and asymmetric MLI cases are presented to validate the correctness and online applicability of the proposed solution.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • DSTED: A Denoising Spatial–Temporal Encoder–Decoder Framework for
           Multistep Prediction of Burn-Through Point in Sintering Process

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      Authors: Feng Yan;Chunjie Yang;Xinmin Zhang;
      Pages: 10735 - 10744
      Abstract: Sinter ore is the main raw material of the blast furnace, and burn-through point (BTP) has a direct influence on the yield, quality, and energy consumption of the ironmaking process. Since iron ore sintering is a very complex industrial process with strong nonlinearity, multivariable coupling, random noises, and time variation, traditional soft-sensor models are hard to learn the knowledge of the sintering process. In this article, a multistep prediction model, called denoising spatial–temporal encoder–decoder, is developed to predict BTP in advance. First, the mechanism analysis is carried out to determine the relevant-BTP variables, and the BTP prediction is defined as a sequence-to-sequence modeling problem. Second, motivated by the random noises of industrial data, a denoising gated recurrent unit (DGRU) is designed to alleviate the impact of noise by adding a denoising gate into the GRU. In this case, the encoder with DGRU can better extract the latent variables of original sequence data. Then, spatial–temporal attention is embedded into the decoder to simultaneously capture the time-wise and variable-wise correlations between the latent variables and the target variable BTP. Finally, the experimental results on the real-world dataset of a sintering process demonstrated that the integrated multistep prediction model is effective and feasible.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • A Simple Structure for Accurate Estimation of Single-Phase Grid Frequency
           Under DC Offset and Both Odd and Even Harmonics

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      Authors: Md. Shamim Reza;Md Maruf Hossain;
      Pages: 10745 - 10751
      Abstract: This article proposes an enhanced frequency-locked loop method for the single-phase grid frequency estimation under dc offset and both odd and even harmonics conditions. The proposed method relies on an adaptive recursive discrete Fourier transform-based frequency error detector and an integral controller. It offers a relatively simple structure and computationally efficient method. It can provide accurate frequency estimation at steady state under grid disturbances and takes a dynamic time of around one and half cycles of the fundamental frequency. The improved performance of the proposed method is verified by comparing it with the results of several existing methods reported in the technical literature. The efficacy of the proposed method is proved using simulated and real-time experimental results.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
  • A Cascaded Integral Action Based Filter for Distorted Conditions

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      Authors: Abdullahi Bamigbade;Vinod Khadkikar;
      Pages: 10752 - 10760
      Abstract: This article proposes a cascaded integral action-based filter by relying on the orthogonal output of a $T/4$ delay block. The proposed filter employs an integrator together with mechanisms involving feedback of the filtered signal and feedforward of its orthogonal input. Based on this approach, the proposed filter addresses the problem of initial state when applying a direct integral action to a sinusoidal voltage. More so, the proposed filter provides notch filtering characteristics at certain harmonic frequencies, thereby achieving improved harmonic rejection in comparison to existing second-order generalized integrator filter. Without frequency adaptivity, the proposed filter achieves fast response, and more importantly, provides excellent filtering of harmonic components at off-nominal frequencies of the supply voltage. Furthermore, dc-offset rejection in the proposed filter is considered together with its FLL implementation for frequency, phase angle, and amplitude estimations. Linearized model and stability evaluation of the proposed filter’s FLL are presented while detailed analytical, simulation, and experimental validation of the proposed filter’s performance for applications involving voltage parameter estimation for synchronization purposes and reference signal generation are provided. Results obtained demonstrate superiority of the proposed filter in terms of harmonic rejection and estimation speed when compared to existing filtering techniques.
      PubDate: Oct. 2022
      Issue No: Vol. 69, No. 10 (2022)
       
 
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