Subjects -> COMPUTER SCIENCE (Total: 2313 journals)
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COMPUTER SCIENCE (1305 journals)                  1 2 3 4 5 6 7 | Last

Showing 1 - 200 of 872 Journals sorted alphabetically
3D Printing and Additive Manufacturing     Full-text available via subscription   (Followers: 27)
Abakós     Open Access   (Followers: 3)
ACM Computing Surveys     Hybrid Journal   (Followers: 29)
ACM Inroads     Full-text available via subscription   (Followers: 1)
ACM Journal of Computer Documentation     Free   (Followers: 4)
ACM Journal on Computing and Cultural Heritage     Hybrid Journal   (Followers: 5)
ACM Journal on Emerging Technologies in Computing Systems     Hybrid Journal   (Followers: 11)
ACM SIGACCESS Accessibility and Computing     Free   (Followers: 2)
ACM SIGAPP Applied Computing Review     Full-text available via subscription  
ACM SIGBioinformatics Record     Full-text available via subscription  
ACM SIGEVOlution     Full-text available via subscription  
ACM SIGHIT Record     Full-text available via subscription  
ACM SIGHPC Connect     Full-text available via subscription  
ACM SIGITE Newsletter     Open Access   (Followers: 1)
ACM SIGMIS Database: the DATABASE for Advances in Information Systems     Hybrid Journal  
ACM SIGUCCS plugged in     Full-text available via subscription  
ACM SIGWEB Newsletter     Full-text available via subscription   (Followers: 3)
ACM Transactions on Accessible Computing (TACCESS)     Hybrid Journal   (Followers: 3)
ACM Transactions on Algorithms (TALG)     Hybrid Journal   (Followers: 13)
ACM Transactions on Applied Perception (TAP)     Hybrid Journal   (Followers: 3)
ACM Transactions on Architecture and Code Optimization (TACO)     Hybrid Journal   (Followers: 9)
ACM Transactions on Asian and Low-Resource Language Information Processing (TALLIP)     Hybrid Journal  
ACM Transactions on Autonomous and Adaptive Systems (TAAS)     Hybrid Journal   (Followers: 10)
ACM Transactions on Computation Theory (TOCT)     Hybrid Journal   (Followers: 11)
ACM Transactions on Computational Logic (TOCL)     Hybrid Journal   (Followers: 5)
ACM Transactions on Computer Systems (TOCS)     Hybrid Journal   (Followers: 19)
ACM Transactions on Computer-Human Interaction     Hybrid Journal   (Followers: 15)
ACM Transactions on Computing Education (TOCE)     Hybrid Journal   (Followers: 9)
ACM Transactions on Computing for Healthcare     Hybrid Journal  
ACM Transactions on Cyber-Physical Systems (TCPS)     Hybrid Journal   (Followers: 1)
ACM Transactions on Design Automation of Electronic Systems (TODAES)     Hybrid Journal   (Followers: 5)
ACM Transactions on Economics and Computation     Hybrid Journal  
ACM Transactions on Embedded Computing Systems (TECS)     Hybrid Journal   (Followers: 4)
ACM Transactions on Information Systems (TOIS)     Hybrid Journal   (Followers: 18)
ACM Transactions on Intelligent Systems and Technology (TIST)     Hybrid Journal   (Followers: 11)
ACM Transactions on Interactive Intelligent Systems (TiiS)     Hybrid Journal   (Followers: 6)
ACM Transactions on Internet of Things     Hybrid Journal   (Followers: 2)
ACM Transactions on Modeling and Performance Evaluation of Computing Systems (ToMPECS)     Hybrid Journal  
ACM Transactions on Multimedia Computing, Communications, and Applications (TOMCCAP)     Hybrid Journal   (Followers: 10)
ACM Transactions on Parallel Computing     Full-text available via subscription  
ACM Transactions on Reconfigurable Technology and Systems (TRETS)     Hybrid Journal   (Followers: 6)
ACM Transactions on Sensor Networks (TOSN)     Hybrid Journal   (Followers: 9)
ACM Transactions on Social Computing     Hybrid Journal  
ACM Transactions on Spatial Algorithms and Systems (TSAS)     Hybrid Journal   (Followers: 1)
ACM Transactions on Speech and Language Processing (TSLP)     Hybrid Journal   (Followers: 11)
ACM Transactions on Storage     Hybrid Journal  
ACS Applied Materials & Interfaces     Hybrid Journal   (Followers: 39)
Acta Informatica Malaysia     Open Access  
Acta Universitatis Cibiniensis. Technical Series     Open Access   (Followers: 1)
Ad Hoc Networks     Hybrid Journal   (Followers: 12)
Adaptive Behavior     Hybrid Journal   (Followers: 8)
Additive Manufacturing Letters     Open Access   (Followers: 3)
Advanced Engineering Materials     Hybrid Journal   (Followers: 32)
Advanced Science Letters     Full-text available via subscription   (Followers: 9)
Advances in Adaptive Data Analysis     Hybrid Journal   (Followers: 9)
Advances in Artificial Intelligence     Open Access   (Followers: 31)
Advances in Catalysis     Full-text available via subscription   (Followers: 7)
Advances in Computational Mathematics     Hybrid Journal   (Followers: 20)
Advances in Computer Engineering     Open Access   (Followers: 13)
Advances in Computer Science : an International Journal     Open Access   (Followers: 18)
Advances in Computing     Open Access   (Followers: 3)
Advances in Data Analysis and Classification     Hybrid Journal   (Followers: 52)
Advances in Engineering Software     Hybrid Journal   (Followers: 26)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 19)
Advances in Human-Computer Interaction     Open Access   (Followers: 19)
Advances in Image and Video Processing     Open Access   (Followers: 20)
Advances in Materials Science     Open Access   (Followers: 19)
Advances in Multimedia     Open Access   (Followers: 1)
Advances in Operations Research     Open Access   (Followers: 13)
Advances in Remote Sensing     Open Access   (Followers: 59)
Advances in Science and Research (ASR)     Open Access   (Followers: 8)
Advances in Technology Innovation     Open Access   (Followers: 5)
AEU - International Journal of Electronics and Communications     Hybrid Journal   (Followers: 8)
African Journal of Information and Communication     Open Access   (Followers: 6)
African Journal of Mathematics and Computer Science Research     Open Access   (Followers: 5)
AI EDAM     Hybrid Journal   (Followers: 2)
Air, Soil & Water Research     Open Access   (Followers: 6)
AIS Transactions on Human-Computer Interaction     Open Access   (Followers: 5)
Al-Qadisiyah Journal for Computer Science and Mathematics     Open Access   (Followers: 2)
AL-Rafidain Journal of Computer Sciences and Mathematics     Open Access   (Followers: 3)
Algebras and Representation Theory     Hybrid Journal  
Algorithms     Open Access   (Followers: 13)
American Journal of Computational and Applied Mathematics     Open Access   (Followers: 8)
American Journal of Computational Mathematics     Open Access   (Followers: 6)
American Journal of Information Systems     Open Access   (Followers: 4)
American Journal of Sensor Technology     Open Access   (Followers: 2)
Analog Integrated Circuits and Signal Processing     Hybrid Journal   (Followers: 15)
Animation Practice, Process & Production     Hybrid Journal   (Followers: 4)
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Data Science     Hybrid Journal   (Followers: 14)
Annals of Mathematics and Artificial Intelligence     Hybrid Journal   (Followers: 16)
Annals of Pure and Applied Logic     Open Access   (Followers: 4)
Annals of Software Engineering     Hybrid Journal   (Followers: 12)
Annual Reviews in Control     Hybrid Journal   (Followers: 7)
Anuario Americanista Europeo     Open Access  
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 3)
Applied and Computational Harmonic Analysis     Full-text available via subscription  
Applied Artificial Intelligence: An International Journal     Hybrid Journal   (Followers: 17)
Applied Categorical Structures     Hybrid Journal   (Followers: 4)
Applied Clinical Informatics     Hybrid Journal   (Followers: 4)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 16)
Applied Computer Systems     Open Access   (Followers: 6)
Applied Computing and Geosciences     Open Access   (Followers: 3)
Applied Mathematics and Computation     Hybrid Journal   (Followers: 31)
Applied Medical Informatics     Open Access   (Followers: 11)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 4)
Applied Soft Computing     Hybrid Journal   (Followers: 13)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 5)
Applied System Innovation     Open Access   (Followers: 1)
Archive of Applied Mechanics     Hybrid Journal   (Followers: 4)
Archive of Numerical Software     Open Access  
Archives and Museum Informatics     Hybrid Journal   (Followers: 97)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 5)
arq: Architectural Research Quarterly     Hybrid Journal   (Followers: 7)
Array     Open Access   (Followers: 1)
Artifact : Journal of Design Practice     Open Access   (Followers: 8)
Artificial Life     Hybrid Journal   (Followers: 7)
Asian Journal of Computer Science and Information Technology     Open Access   (Followers: 3)
Asian Journal of Control     Hybrid Journal  
Asian Journal of Research in Computer Science     Open Access   (Followers: 4)
Assembly Automation     Hybrid Journal   (Followers: 2)
Automatic Control and Computer Sciences     Hybrid Journal   (Followers: 6)
Automatic Documentation and Mathematical Linguistics     Hybrid Journal   (Followers: 5)
Automatica     Hybrid Journal   (Followers: 13)
Automatika : Journal for Control, Measurement, Electronics, Computing and Communications     Open Access  
Automation in Construction     Hybrid Journal   (Followers: 8)
Balkan Journal of Electrical and Computer Engineering     Open Access  
Basin Research     Hybrid Journal   (Followers: 7)
Behaviour & Information Technology     Hybrid Journal   (Followers: 32)
BenchCouncil Transactions on Benchmarks, Standards, and Evaluations     Open Access   (Followers: 3)
Big Data and Cognitive Computing     Open Access   (Followers: 5)
Big Data Mining and Analytics     Open Access   (Followers: 10)
Biodiversity Information Science and Standards     Open Access   (Followers: 1)
Bioinformatics     Hybrid Journal   (Followers: 216)
Bioinformatics Advances : Journal of the International Society for Computational Biology     Open Access   (Followers: 1)
Biomedical Engineering     Hybrid Journal   (Followers: 11)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 11)
Briefings in Bioinformatics     Hybrid Journal   (Followers: 43)
British Journal of Educational Technology     Hybrid Journal   (Followers: 93)
Bulletin of Taras Shevchenko National University of Kyiv. Series: Physics and Mathematics     Open Access  
c't Magazin fuer Computertechnik     Full-text available via subscription   (Followers: 1)
Cadernos do IME : Série Informática     Open Access  
CALCOLO     Hybrid Journal  
CALICO Journal     Full-text available via subscription  
Calphad     Hybrid Journal  
Canadian Journal of Electrical and Computer Engineering     Full-text available via subscription   (Followers: 14)
Catalysis in Industry     Hybrid Journal  
CCF Transactions on High Performance Computing     Hybrid Journal  
CCF Transactions on Pervasive Computing and Interaction     Hybrid Journal  
CEAS Space Journal     Hybrid Journal   (Followers: 6)
Cell Communication and Signaling     Open Access   (Followers: 3)
Central European Journal of Computer Science     Hybrid Journal   (Followers: 4)
CERN IdeaSquare Journal of Experimental Innovation     Open Access  
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 1)
Chaos, Solitons & Fractals : X     Open Access   (Followers: 1)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 13)
ChemSusChem     Hybrid Journal   (Followers: 7)
China Communications     Full-text available via subscription   (Followers: 8)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
Chip     Full-text available via subscription   (Followers: 2)
Ciencia     Open Access  
CIN : Computers Informatics Nursing     Hybrid Journal   (Followers: 11)
Circuits and Systems     Open Access   (Followers: 16)
CLEI Electronic Journal     Open Access  
Clin-Alert     Hybrid Journal   (Followers: 1)
Clinical eHealth     Open Access  
Cluster Computing     Hybrid Journal   (Followers: 1)
Cognitive Computation     Hybrid Journal   (Followers: 2)
Cognitive Computation and Systems     Open Access  
COMBINATORICA     Hybrid Journal  
Combinatorics, Probability and Computing     Hybrid Journal   (Followers: 4)
Combustion Theory and Modelling     Hybrid Journal   (Followers: 18)
Communication Methods and Measures     Hybrid Journal   (Followers: 12)
Communication Theory     Hybrid Journal   (Followers: 29)
Communications in Algebra     Hybrid Journal   (Followers: 1)
Communications in Partial Differential Equations     Hybrid Journal   (Followers: 2)
Communications of the ACM     Full-text available via subscription   (Followers: 59)
Communications of the Association for Information Systems     Open Access   (Followers: 15)
Communications on Applied Mathematics and Computation     Hybrid Journal   (Followers: 1)
COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering     Hybrid Journal   (Followers: 4)
Complex & Intelligent Systems     Open Access   (Followers: 1)
Complex Adaptive Systems Modeling     Open Access  
Complex Analysis and Operator Theory     Hybrid Journal   (Followers: 2)
Complexity     Hybrid Journal   (Followers: 8)
Computación y Sistemas     Open Access  
Computation     Open Access   (Followers: 1)
Computational and Applied Mathematics     Hybrid Journal   (Followers: 3)
Computational and Mathematical Methods     Hybrid Journal  
Computational and Mathematical Methods in Medicine     Open Access   (Followers: 2)
Computational and Mathematical Organization Theory     Hybrid Journal   (Followers: 1)
Computational and Structural Biotechnology Journal     Open Access   (Followers: 1)
Computational and Theoretical Chemistry     Hybrid Journal   (Followers: 11)
Computational Astrophysics and Cosmology     Open Access   (Followers: 6)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 13)
Computational Biology Journal     Open Access   (Followers: 6)
Computational Brain & Behavior     Hybrid Journal   (Followers: 1)
Computational Chemistry     Open Access   (Followers: 3)
Computational Communication Research     Open Access   (Followers: 1)
Computational Complexity     Hybrid Journal   (Followers: 5)
Computational Condensed Matter     Open Access   (Followers: 1)

        1 2 3 4 5 6 7 | Last

Similar Journals
Journal Cover
COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering
Journal Prestige (SJR): 0.22
Citation Impact (citeScore): 1
Number of Followers: 4  
 
Hybrid Journal Hybrid journal   * Containing 6 Open Access Open Access article(s) in this issue *
ISSN (Print) 0332-1649 - ISSN (Online) 2054-5606
Published by Emerald Homepage  [360 journals]
  • Shape optimization of synchronous reluctance motor using sensitivity
           information for multiple objective functions

    • Free pre-print version: Loading...

      Authors: Hiroki Shigematsu , Shinji Wakao , Hiroaki Makino , Katsutoku Takeuchi , Makoto Matsushita
      Abstract: This paper aims to further improve the efficiency of multi-objective optimization design of synchronous reluctance motors (SynRMs) using the level set (LS) method, which has the advantage of obtaining a practical shape. The solutions obtained by gradient methods tend to be local ones due to the multi-modality of the objective function, especially when multiple objective functions. A huge number of trial calculations are required to obtain a high-quality and broadly distributed Pareto front. Therefore, it is indispensable to effectively get out of the local solutions in the optimization process with the LS method. The authors propose a novel method appropriately switching multiple objective functions with high independence of sensitivity information. The authors adopt highly independent mathematical expressions for the objective functions of the average torque and torque ripple. In addition, the authors repeatedly perform the optimization while appropriately selecting the sensitivity information of one objective function from multiple ones, which enables the authors to effectively break out of local solutions in the optimization process. The proposed method was applied to the shape optimization of SynRM flux barriers and successfully searched a more extensive and advanced Pareto front in comparison with the conventional method. The proposed method adopts search spaces with mathematical high independence for average torque and torque ripple. In the optimization process, when the solution search is judged to get stuck by several criteria, the search space is alternately switched to effectively get out of local solutions.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-05-18
      DOI: 10.1108/COMPEL-10-2021-0380
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Modelling of low-speed magnetic gear with viscose ferrofluid

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      Authors: Valentin Mateev , Iliana Marinova
      Abstract: In this paper, a computational model of a coaxial magnetic gear (MG) design with viscose ferrofluid between rotors is proposed. Viscose ferrofluid is used to decrease the magnetic reluctance and therefore creates higher magnetic torque. However, viscose friction of ferrofluid is undesirable and must be minimised in this particular application. MG is supposed to operate under low rotational speeds, where the dynamic viscose friction is very low, and the effects of the viscose ferrofluid over the MG’s efficiency must be estimated. The paper aims to analyze the performance of MG with viscose ferrofluid and to estimate the MG efficiency by computational model using finite element method (FEM). An MG design with viscose ferrofluid between the outer low-speed rotor and modulating steel segments was modelled as a coupled transient magnetic field problem and a kinematic model with viscous friction coefficients derived from a previously computed fluid dynamics model. The proposed computational implementation is suitable for homogeneous magnetic fluid modelling in electromagnetic actuators and rotational machines. The results regarding power and torque transmission of MG were obtained by coupled finite element modelling. The efficiency of MG significantly decreased due to ferrofluid friction. The described MG design with viscose ferrofluid is a novel device with new operational characteristics, and new results for the effects of viscose ferrofluid friction in the outer magnetic field over the MG efficiency are estimated.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-05-17
      DOI: 10.1108/COMPEL-07-2021-0233
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Performance enrichment in optimal location and sizing of wind and solar PV
           

    • Free pre-print version: Loading...

      Authors: Vijay Raviprabhakaran
      Abstract: The distributed generation (DG) proper placement is an extremely rebellious concern for attaining their extreme potential profits. This paper aims to propose the application of the communal spider optimization algorithm (CSOA) to the performance model of the wind turbine unit (WTU) and photovoltaic (PV) array locating method. It also involves the power loss reduction and voltage stability improvement of the ring main distribution system (DS). This paper replicates the efficiency of WTU and PV array enactment models in the placement of DG. The effectiveness of the voltage stability factor considered in computing the voltage stability levels of buses in the DS is studied. The voltage stability levels are augmented, and total losses are diminished for the taken bus system. The accomplished outcomes exposed the number of PV arrays accompanied by the optimal bus location for various penetration situations. The optimal placement and sizing of wind- and solar-based DGs are tested on the 15- and 69-test bus system. Moreover, the projected CSOA algorithm outperforms the PSOA, IAPSOA, BBO, ACO and BSO optimization techniques.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-05-17
      DOI: 10.1108/COMPEL-12-2021-0495
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Magnetostrictive hysteretic properties estimation of electrical steel
           sheet under external stress using improved ADSM model

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      Authors: Mengxing Li , YanLi Zhang , Ying Jing , Zhen Wang , Dexin Xie
      Abstract: The purpose of this paper is to improve the modeling accuracy of the magnetostrictive hysteretic characteristics by introducing hysteresis energy instead of pinning energy in the assembled domain structure model (ADSM). First, the magnetostrictive characteristics and the domain movement process in an electrical steel sheet are measured and observed. The reasons for the influence of stress on magnetostriction are discussed on the mesoscopic level. Second, the ADSM model using the hysteresis energy is investigated to estimate the influence of external stress. Finally, the simulation results of the modified ADSM model are compared with the experimental data under the same calculation conditions. The results show that the improved model not only explains the cause of hysteresis clearly from the perspective of the magnetic moment but also improves the modeling ability of magnetostrictive hysteretic. The magnetostriction in electrical steel lags behind the external magnetic field, and it is significant for reducing core vibration to estimate the magnetostrictive hysteretic property accurately. This paper proposes an effective approach to model the hysteretic characterization of magnetostriction.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-05-16
      DOI: 10.1108/COMPEL-01-2022-0059
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Analysis of the operation principle for tubular flux-switching permanent
           magnet linear machine

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      Authors: Guozhen Zhang , Rui Nie , Jikai Si , Xiaohui Feng , Changli Wang
      Abstract: This study aims to unveil the generation mechanism of the thrust force in a tubular flux-switching permanent magnet (PM) linear (TFSPML) machine; the operation principle of the TFSPML machine is analyzed. First, the air-gap flux density harmonic characteristics excited by PMs and armature windings are investigated and summarized based on a simple magnetomotive force (MMF)-permeance model. Then, the air-gap field modulation theory is applied in analyzing the air-gap flux density harmonics that contribute to the electromagnetic force. In addition, a simple method for separating the end force of the TFSPML machine is proposed, which is a significant foundation for the comprehensive analysis of this type of machine. As a result, the operation principle of the TFSPML machine is thoroughly revealed. The analysis shows that the average electromagnetic force is mainly contributed by the air-gap dominant harmonics, and the thrust force ripple is mainly caused by the end force. In this paper, the operation principle of the TFSPML machine is analyzed from the perspective of air-gap field modulation.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-05-13
      DOI: 10.1108/COMPEL-01-2022-0024
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • The use of finite elements modeling to analyze phase shifting transformer
           in steady-state service conditions

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      Authors: Marcel Ciesielski , Pawel Zygmunt Witczak
      Abstract: The aim of this paper is to find a fast-acting numerical model of the phase shifter. The 3D FE model of the investigated unit is presented and compared with the results of the measurements. Due to its size, it is not suitable for transient analyses. The simplified 2D finite elements approach is discussed afterwards, with the identity of the magnetic energy stored in both models as the criterion of similarity between 2D and 3D models. The introduction of scaling factors for the magnetic permeability values in particular volumes of the two-transformer set of the phase shifter enabled acceptable accuracy in calculations of the basic exploitation parameters of the phase shifter. The developed methodology allows the analysis of the exploitation conditions of two separated transformers connected in a power grid inside the single finite elements model. Although the numerical models of power transformers are extensively discussed in the literature, the usage of the equivalent fast 2D model for the representation of two cooperating transformers at load conditions was not published yet.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-05-13
      DOI: 10.1108/COMPEL-11-2021-0449
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • An analytical model for stator yokeless radial flux dual rotor permanent
           magnet synchronous machine

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      Authors: Minglei Yang , Zaimin Zhong , Qinglong Wang , Zhongshu Shao
      Abstract: The purpose of this study is to propose an analytical model with consideration of the permeability of soft-magnetic materials, which can predict the magnetic field distribution more accurately and facilitate the initial design and parameter optimization of the machine. This paper proposes an analytical model of stator yokeless radial flux dual rotor permanent magnet synchronous machine (SYRFDR-PMSM) with the consideration of magnetic saturation of soft-magnetic material. The analytical model of SYRFDR-PMSM is divided into seven regions along the radial direction according to the different excitation source and magnetic medium, and the iron permeability in each region is considered based on the Maxwell–Fourier method and Cauchy’s product theorem. The magnetic vector potential of each region is obtained by the Laplace’s or Poisson’s equation, and the magnetic field solution is determined using the boundary conditions of adjacent regions. The inner and outer air-gap flux density, flux linkage, output torque, etc., of SYRFDR-PMSM are predicted by analytical model, resulting in good agreement with that of finite element model. Additionally, the SYRFDR-PMSM prototype is manufactured and the correctness of analytical model is further verified by experiments on no-load back electromotive force and current–torque curve. Reasonable design of the slot opening width and pole arc coefficient can improve the average output torque and reduce output torque ripple. The analytical model proposed in this paper assumes that the permeability of soft-magnetic material is a fixed value. However, the actual iron’s permeability varies nonlinearly; thus, the prediction results of the analytical model will have some deviations from the actual machine. The main contribution of this paper is to propose an accurate magnetic field analytical model of SYRFDR-PMSM. It takes into account the permeability of soft-magnetic material and slot opening, which can quickly and accurately predict the electromagnetic performance of SYRFDR-PMSM. It can provide assistance for the initial design and optimization of SYRFDR-PMSM.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-05-12
      DOI: 10.1108/COMPEL-12-2021-0485
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Reconfigurable dual element dual band MIMO antenna for 5G (Sub-6 GHz) and
           WLAN applications

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      Authors: Ajit Kumar Singh , Santosh Kumar Mahto , Rashmi Sinha
      Abstract: This study aims to present dual band reconfigurable MIMO antenna for 5G (sub-6 GHz) and WLAN applications. To achieve optimum bandwidth, radiation pattern and radiation efficiency, the defected ground structure (DGS) and a rectangular stub connected with the DGS are used. To further cover the sub-6 GHz spectrum (3.4–3.6 GHz) for future 5G communications, a two-element multi-input multi-output (MIMO) antenna configuration is designed by using the single element antenna. The proposed reconfigurable MIMO antenna using a PIN diode is designed on an FR4 substrate with a dielectric constant of 4.4 and a loss tangent of 0.02 and a 35 × 20 × 1.6 mm3 dimension. The proposed antenna achieved dual operating bands of 3.4–4.1 GHz (5 G sub-6GHz applications) and 4.99–5.16 GHz (WLAN application) in the D = ON state. For D = OFF state, the proposed antenna achieved 3.55–3.65 GHz and 3.66–4.05 GHz frequency bands for 5G (sub-6GHz) applications. In terms of the envelop correlation coefficient, diversity gain, mean effective gain, total active reflection coefficient and isolation between the ports, the proposed antenna’s diversity performance characteristics are investigated and the obtained values are 0.05, 9.9 dB, ±3dB, −4dB, −15dB, respectively. The fabricated prototype antenna on FR4 substrate has measurable parameters that are in good agreement with the simulated findings. Due to hardware design limitations, there is a minor difference between software and hardware results. The proposed MIMO antenna is compact and reconfigurable for 5G (sub-6GHz) and WLAN applications, and from the graph, the measurements and simulations have been found to be in close agreement.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-05-09
      DOI: 10.1108/COMPEL-02-2022-0091
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Novel coordinated power sources switching strategy for transient
           performance enhancement of hybrid electric vehicles

    • Free pre-print version: Loading...

      Authors: Adel Oubelaid , Nabil Taib , Toufik Rekioua
      Abstract: The purpose of this paper is the investigation of a new coordinated switching strategy to improve the transient performance of a fuel cell (FC)- supercapacitor (SC) electric vehicle. The proposed switching strategy protects FCs from large currents drawn during abrupt power variations. Furthermore, it compensates the poor FC transient response and suppresses the transient ripples occurring during power source switching instants. Coordinated power source switching is achieved using three different transition functions. Vehicle model is fractioned into computational and console subsystems for its simulation using real time (RT) LAB simulator. Blocs containing coordination switching strategy, power sources models and their power electronics interface are placed in the computational subsystem that will be executed, in RT, on one of real time laboratory simulator central processing unit cores. Coordination switching strategy resulted in reducing transient power ripples by 90% and direct current (DC) bus voltage fluctuations by 50%. Switching through transition functions compensated the difference between FC and SC transient responses responsible for transient power ripples. Among the three proposed transition functions, linear transition function resulted in the best transient performances. The proposed coordinated switching strategy allows the control of the switching period duration. Furthermore, it enables the choice of adequate transition functions that fit the dynamics of power sources undergoing transition. Also, the proposed switching technique is simple and does not require the knowledge of system parameters or the complex control models.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-05-05
      DOI: 10.1108/COMPEL-10-2021-0399
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • A tunable broadband THz absorber using periodic arrays of graphene disks

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      Authors: Amir Ali Mohamad Khani , Toktam Aghaee , Jalil Mazloum , Morteza Jamali
      Abstract: A wide band perfect THz absorber is presented in this work. The structure includes two layers of graphene disks on the silicon dioxide dielectric layer while a golden plate is placed at the bottom to act as a fully reflecting mirror against THz waves. According to the simulations, the device is robust enough to show independent operation versus layers thicknesses variations, chemical potentials mismatches and changing of electron relaxation time. The designed THz absorber in this work is an appropriate basic block for several applications in THz optical systems such as sensors, detectors and modulators. The layers in the proposed device are modeled via passive circuit elements and consequently, the equivalent circuit of the device is calculated. Leveraging the developed equivalent circuit model (ECM) and impedance matching concept, the proposed device is designed to perfect absorption with 4.7 THz bandwidth that possesses over 90% absorption. Ample simulations are performed using MATLAB (ECM) and CST (finite element method) to verify the superior performance of the device. According to the simulations, the device is robust enough to show independent operation versus layers thicknesses variations, chemical potentials mismatches and changing of electron relaxation time. This work reports a wideband THz absorber, composed of two graphene layers. This paper considers the circuit model representation for two different layers of the device. For a unique structure, a highly tunable response versus chemical potential is obtained. The circuit model approach and impedance matching theory are exploited to reduce computational time regarding conventional approaches. A wide band absorber in THz band is presented. Leveraging circuit model approach and impedance matching theory, the design procedure is simplified regarding CPU time and memory requirements compared to conventional methods. Detailed calculations and ample simulations verify the performance excellency of the device to absorb THz incident waves in 2–6.5 THz frequencies. Also, the robustness of the device is investigated versus parameters mismatches like layers thicknesses and chemical potentials values. According to the simulations and absorption response, the proposed device is an appropriate block to be used in THz optical systems such as detectors, imaging systems and optical modulators.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-05-03
      DOI: 10.1108/COMPEL-09-2021-0339
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Finite element method based co-simulation platform for the numerical
           analysis of motor drive system

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      Authors: Yunpeng Zhang , Huiwen Huang , Dingguo Shao , Xinsheng Yang , Changgeng Zhang
      Abstract: This study aims to develop a finite element method based co-simulation platform for the numerical analysis of motor drive system. With the rising requirement of industry, the comprehensive design of motor drive systems has attracted increasing attentions. An accurate model, which considers the coupling between motor and its drive system, is vital for the analysis and design of motor drive system. Considering the coupling relationship between motor and its drive system, a flexible and extensible co-simulation platform of motor drive system is developed with the C++ language and finite element machine model to carry out the comprehensive analysis of motor drive system. The control system simulation program developed with C++ language adopts the same discrete form as the single-chip microcomputer and can simulate the interrupt mechanism, making the simulation closer to the actual control system. With the finite element analysis results of current step, the winding input voltage of next step is calculated by the executable program of control system and is fed into the finite element analysis, forming the two-way coupling analysis of drive system. Preliminary studies, such as calculation of machine core losses fed by inverters, and control parameters optimization, are conducted with this platform, which shows the flexibility and expansibility of this platform. The power inverter circuit along with the controller is modeled using the C++ language, and embedded into the finite element machine model to achieve more realistic motor drive system simulation and complex functions.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-04-29
      DOI: 10.1108/COMPEL-01-2022-0048
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Determination of maximum power point from photovoltaic system using
           genetic algorithm

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      Authors: Angela Najdoska , Goga Vladimir Cvetkovski
      Abstract: The purpose of this paper is to present a novel approach to the determination of the maximum power point (MPP) in the photovoltaic system using genetic algorithm (GA). The optimization is realised on two types of photovoltaic (PV) modules: monocrystalline and polycrystalline solar modules, with the same rated peak power (400 Wp) but different electrical output data. The proposed algorithm is a nature-based algorithm that uses genetic operators such as reproduction, crossover and mutation to realise the search through the investigated area of solutions. To determine the MPP of the PV modules, a two-diode model of a PV cell is used. Based on the input electrical data for the analysed PV module, as well as the mathematical model of the PV, the algorithm can estimate the current and voltage at the MPP for given solar irradiation and cell temperature. The analysis is made for several different irradiations, but in work, the results are presented for irradiations of: 100, 500 and 1,000 W/m2 and cell temperatures of 0, 25 and 40 °C. From the presented results and performed analysis, it can be concluded that GA gives adequate results for both modules and for all working conditions. From the obtained results, it can be concluded that the optimization algorithm performs better when applied to the monocrystalline module works better especially in conditions with larger cell temperature, in comparison with the performance of the optimization algorithm applied to the polycrystalline module. On the other hand, the optimization algorithm applied to the polycrystalline module works better for the other working scenarios with smaller cell temperatures. From the performed analysis, it can be concluded that the use GA as an optimization tool for the determination of the MPP can be successfully implemented. In addition, to improve the overall performance of the PV system, it is also necessary to forecast the weather conditions of the location where the PV system would be installed to forecast the cell temperature and the solar irradiation. This is necessary to choose the right PV module and inverter for the given location. An optimization technique using GA as an optimization tool has been developed and successfully applied in the determination of the MPP for a PV system. The results are compared with the analytically determined values as well as with the values given by the producer, and they show good agreement.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-04-26
      DOI: 10.1108/COMPEL-11-2021-0445
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Higher-order accurate finite-difference simulation for tunnel propagation
           modeling

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      Authors: Hafiz Faiz Rasool , Muhammad Ali Qureshi , Abdul Aziz , Zain Ul Abiden Akhtar , Usman Ali Khan
      Abstract: This paper aims to improve the computational efficiency of higher-order accurate Noye–Hayman [NH (9,9)] implicit finite difference scheme for the solution of electromagnetic scattering problems in tunnel environments. The proposed method consists of two major steps: First, the higher-order NH (9,9) scheme is numerically discretized using the finite-difference method. The second step is to use an algorithm based on hierarchical interpolative factorization (HIF) to accelerate the solution of this scheme. It is observed that the simulation results obtained from the numerical tests illustrate very high accuracy of the NH (9,9) method in typical tunnel environments. HIF algorithm makes the NH (9,9) method computationally efficient for two-dimensional (2D) or three-dimensional (3D) problems. The proposed method could help in reducing the computational cost of the NH (9,9) method very close to O(n) usual O(n3) for a full matrix. For simplicity, in this study, perfect electric conductor boundary conditions are considered. Future research may also include the utilization of meteorological techniques, including the effects of backward traveling waves, and make comparisons with the experimental data. This study is directly applicable to typical problems in the field of tunnel propagation modeling for both national commercial and military applications.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-04-20
      DOI: 10.1108/COMPEL-07-2021-0256
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Voltage instability curtailment and quality improvement with phasor
           measurement unit in power system

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      Authors: Kabra Preeti , Donepudi Sudha Rani
      Abstract: The earlier methods are more resilient to improvements such as load shift and path change. This results in problems such as a voltage drop and a high reactive flux. In addition, due to the delay, congestion or interruption of the transmission, the system cannot receive all phasor measurement unit (PMU) measurements at the relevant time as well as the presence of noise in the received data. With the development of wide area measurement system technologies, it seems to be possible to track voltage stability online via time-stamped PMUs. As the voltage instability causes a voltage decomposition, voltage instability is one of the most important problems when monitoring the power supply. This harmonic distortion significantly decreases the data quality in the grid. As a result, instability ascertainment based on PMU has been suggested as a method for detecting voltage instability in power systems monitored with PMU. In addition, a technique called instability amendment via load dropping has been proposed to keep the device from collapsing due to voltage failure. To improve the power output, the power prominence melioration technique was developed. This proposed system has been implemented in MATLAB Simulink and compared with the recent researches.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-04-20
      DOI: 10.1108/COMPEL-09-2021-0331
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Triple-speed coaxial magnetic gear for wind turbine applications:
           introduction and comprehensive analysis

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      Authors: Ali Moghimi , Mahmood Hosseini Aliabadi , Hassan Feshki Farahani
      Abstract: This paper aims to introduce a new structure for coaxial magnetic gears. The study discusses the design and electromagnetic modeling of a triple-speed coaxial magnetic gear (TSCMG) for three different levels of torques in special applications such as wind energy conversion and electrical vehicles. The proposed TSCMG consists of inner, middle and outer rotor, which has one rotor more than its conventional counterpart. The suggested TSCMG’s related equations such as transform ratio and torque are calculated, then TSCMG is simulated in a finite element environment. A comprehensive study has been done on TSCMG, and results are compared with two other magnetic gears with the same volume but two speeds. The obtained results show that the proposed structure for TSCMGs is significantly practical and applicable in higher ranges of torques. Finally, an experimental TSCMG is prototyped to verify the results. The achievements are excellent and confirm that TSCMG can be used as powerful equipment in a wide range of application like permanent wind turbines to generate electricity in 24 h per every single day.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-04-15
      DOI: 10.1108/COMPEL-01-2022-0001
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Prediction of hysteresis losses by an advanced vector hysteresis stop
           model with threshold surfaces

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      Authors: Xiao Xiao , Fabian Müller , Martin Marco Nell , Kay Hameyer
      Abstract: The ordinary vector hysteresis stop model with constant threshold values is not able to prohibit the hysteretic property after the saturation correctly. This paper aims to develop an improved vector hysteresis stop model with threshold surfaces. This advanced anisotropic vector hysteresis stop model can represent the magnetic saturation properties and the hysteresis losses under alternating and rotating magnetizations. By integrating anhysteretic surfaces into the elastic element of a vector hysteresis stop model, the anisotropy of the permeability of an electrical steel sheet can be represented. Instead of the commonly used constant threshold value for plastic elements of the hysteresis model, threshold surfaces are applied to the stop hysterons. The threshold surfaces can be derived directly from measured alternating major loops of the material sample. By saturated polarization, the constructed threshold surfaces are vanishing. In this way, the reversible magnetic flux density is in the same direction of the applied magnetic flux density. Thus, the saturation properties are satisfied. Analyzing the measurements of the electrical steel sheets sample obtained from a rotational single sheet tester shows that the clockwise (CW) and counter-CW (CCW) rotational hysteresis losses decrease by saturated flux density. At this state, instead of the domain wall motion, the magnetization rotation is dominant in the material. As a result, the hysteresis losses, which are related to the domain wall motion, are vanished near the saturation. In one stop operator, the plastic element represents the hysteresis part of the model. Integrating threshold surface into the plastic element, the hysteresis part can be modified to zero near the saturation to represent the saturation properties. The results of this work demonstrate that the presented vector hysteresis stop model allows simulation of anisotropic hysteresis effects, alternating and rotating hysteresis losses. The parameters of the hysteresis model are determined by comparing the measured and modeled minor loops in different alternating magnetization directions. With the identified parameters, the proposed model is excited with rotated excitations in CW and CCW directions. The rotated hysteresis losses, derived from the model, are then compared with those experimentally measured. The modified vector stop model can significantly improve the accuracy of representing hysteresis saturations and losses.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-04-15
      DOI: 10.1108/COMPEL-11-2021-0434
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Proposing a sequential iterative method based on a per-unit model for
           rotor shape optimization in permanent magnet assisted synchronous
           reluctance motors

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      Authors: Ali Jamali Fard , Mojtaba Mirsalim
      Abstract: During the design process of synchronous reluctance motors (SynRMs), one crucial step, after its main dimensioning, is optimizing the rotor geometry for maximum average torque and minimum torque ripple. However, because of the complexity of rotor flux-barrier layers geometry, the number of rotor geometrical parameters is high and this step could be quite complex and time-consuming. To obtain a good performance, one needs a robust algorithm to optimize the rotor geometry. The purpose of this paper is to present a sequential iterative method for rotor shape optimization in SynRMs based on the per-unit rotor model to maximize the average torque and minimize the torque ripple. In the presented method, at first, rotor geometrical parameters are classified into several groups based on their geometrical similarities, and then optimization is done on these individual groups iteratively. The method starts with an arbitrary feasible rotor geometry and proceeds to optimize it. Because the method’s performance depends on initial rotor geometry, different cases are studied to investigate the convergence and robustness of the method. The MATLAB software is used to implement the optimization algorithm, and the ANSYS Maxwell software is used for the finite element analysis. The performance of the proposed method is studied on a three-phase 0.75 kW-1,500 rpm permanent magnet assisted SynRM. The results show that the method improves the average torque while reducing the torque ripple. Even if the method starts with an inappropriate initial rotor geometry, it is robust enough and converges within an acceptable number of iterations. The value of this paper is in introducing a per-unit rotor model. When the authors optimize the rotor geometry for a specific motor rating, it can be scaled up or down for other ratings with little effort. In this work, the number of rotor poles is four and the number of rotor flux-barrier layers per pole is three. Other combinations could be analyzed in future studies.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-04-12
      DOI: 10.1108/COMPEL-09-2021-0340
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Participation Factor based analysis of PVSC type Multi-Input Zeta-SEPIC
           dc-dc converter

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      Authors: Phanindra Thota , Amarendra Reddy Bhimavarapu , V.V.S. Bhaskara Reddy Chintapalli
      Abstract: This study aims to propose a new non-isolated Multi-Input Zeta-SEPIC (MIZS) dc–dc converter for renewable energy sources integration with different voltage levels (low-voltage source, high-voltage source). The chosen configuration of the converter is capable of performing bucking as well as boosting operations in various modes of operation. Parameters of the selected MIZS converter are designed using the time-domain analysis. The selected converter belongs to the sixth-order family with two switches and six energy storage elements. State-space model of the converter is developed for each mode of operation, and using these individual state-space models, an average state-space model of the converter useful to carry out detailed analysis for different operating conditions is developed. Analysis related to operational stability of the converter is also carried out using Participation Factor (PaF)-based Eigen value analysis. Using the PaF-based Eigen analysis, participation of the various state variables in different Eigen modes and vice versa is carried out. Performance of the converter for different parameter variations in the allowable range is determined and the same has been used to find the operational stability of the converter under different modes of operation. The selected converter has low inductor ripple currents and output voltage ripples when delivering the power to load. Because operational stability of the converter under various operating conditions is one of the key performance indicators for selecting a particular type of converter, PaF-based Eigen value analysis has been carried out using the average state-space model developed for the selected MIZS converter. Operational stability analysis of the converter is carried out for parameter variations also. In addition, participation of the various states in each Eigen mode and vice versa have been analyzed for designed parameter values and also variation within the specified range of variations.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-04-12
      DOI: 10.1108/COMPEL-10-2021-0363
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Multiobjective optimization based on polynomial chaos expansions in the
           design of inductive power transfer systems

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      Authors: Yao Pei , Lionel Pichon , Mohamed Bensetti , Yann Le Bihan
      Abstract: The purpose of this study is to decrease the computation time that the large number of simulations involved in a parametric sweep when the model is in a three-dimensional environment. In this paper, a new methodology combining the PCE and a controlled, elitist genetic algorithm is proposed to design IPT systems. The relationship between the quantities of interest (mutual inductance and ferrite volume) and structural parameters (ferrite dimensions) is expressed by a PCE metamodel. Then, two objective functions corresponding to mutual inductance and ferrite volume are defined. These are combined together to obtain optimal parameters with a trade-off between these outputs. According to the number of individuals and the generations defined in the optimization algorithm in this paper, it needs to calculate 20,000 times in a 3D environment, which is quite time-consuming. But for PCE metamodel of mutual inductance M, it requires at least 100 times of calculations. Afterward, the evaluation of M based on the PCE metamodel requires 1 or 2 s. So compared to a conventional optimization based on the 3D model, it is easier to get optimized results with this approach and it saves a lot of computation time. The multiobjective optimization based on PCEs could be helpful to perform the optimization when considering the system in a realistic 3D environment involving many parameters with low computation time.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-04-12
      DOI: 10.1108/COMPEL-10-2021-0393
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Two-dimensional analytical model for five-phase fault-tolerant
           permanent-magnet vernier machines

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      Authors: Ghazal Mirzavand , Akbar Rahideh
      Abstract: This study aims to extract an analytical model for five-phase fault-tolerant permanent-magnet vernier machines (FTPMVMs) based on the analytical solution of Maxwell’s equations, which has some advantages than the finite element model. FTPMVMs enhance the torque density by combining the vernier characteristics and the fault-tolerant feature. The principle operation of FTPMVMs is discussed based on the magnetic field modulation due to both permanent magnets and armature current. The analytical solution of the magnetic vector potential in each sub-region is obtained based on the sub-domain technique. According to the calculated magnetic vector potential, the magnetic flux density, torque, self- and mutual inductance and back-electromotive force are calculated. The FEM is used to validate the results obtained from the proposed analytic model. Two-dimensional analytical method is used to obtain the electromagnetic model of FTPMVMs.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-04-07
      DOI: 10.1108/COMPEL-07-2021-0263
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Analysis of nonlinear circuit by symplectic conservative perturbation
           method

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      Authors: Hongwei Yang , Yingying Wang , Meng Zhang , Lianchun Long
      Abstract: This paper aims to provide a symplectic conservation numerical analysis method for the study of nonlinear LC circuit. The flux linkage control type nonlinear inductance model is adopted, and the LC circuit can be converted into the Hamiltonian system by introducing the electric charge as the state variable of the flux linkage. The nonlinear Hamiltonian matrix equation can be solved by perturbation method, which can be written as the sum of linear and nonlinear terms. Firstly, the linear part can be solved exactly. On this basis, the nonlinear part is analyzed by the canonical transformation. Then, the coefficient matrix of the obtained equation is still a Hamiltonian matrix, so symplectic conservation is achieved. Numerical results reveal that the method proposed has strong stability, high precision and efficiency, and it has great advantages in long-term simulations. This method provides a novel and effective way in studying the nonlinear LC circuit.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-04-07
      DOI: 10.1108/COMPEL-08-2021-0275
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Impact of the radius of double pancake windings on the electromagnetic
           behavior of high temperature superconducting transformer

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      Authors: Hamed Attar , Ahmad Moradnouri , Reza Mirghaforian , Arsalan Hekmati
      Abstract: It has constantly been important to investigate the distribution of magnetic fields in high temperature superconducting (HTS) transformers because the high magnetic field applied to the HTS tapes reduces the critical current and increases the ac losses. The purpose of this study is investigation of the impact of the radius of double pancake windings on the electromagnetic behavior of HTS transformer. In this paper, by changing the radius of the windings in a step-by-step manner in two modes, the electromagnetic behaviors in double pancakes (DPs) of a single-phase HTS transformer have been investigated. In this paper a 15.4 kVA single-phase HTS transformer has been designed and simulated using the finite element method, using COMSOL multiphysics software. The effect of changing the radius of the low-voltage (LV) and high-voltage (HV) windings on the electromagnetic parameters such as distribution of circulating currents and magnetic field in the LV DP windings has been investigated. According to the results, by increasing the radius of the LV winding, the electromagnetic behavior of the highest and lowest DPs becomes highly undesirable, while in other DPs, it becomes desirable. The same thing happens by increasing the radius of the LV and HV windings, but with much less intensity. Therefore, according to Ce, the most optimal case is when the two windings (HV and LV) are close to each other and to the core, and if the radius needs to be increased, it is better to increase the radius of both windings. For the first time, the impact of the radius of DP windings on the electromagnetic behavior of HTS transformer has been investigated.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-04-04
      DOI: 10.1108/COMPEL-08-2021-0314
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Modelling and experimental verification of temperature effects on back
           electromotive force waveforms in a line start permanent magnet synchronous
           motor

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      Authors: Mariusz Baranski , Wojciech Szelag , Wieslaw Lyskawinski
      Abstract: This paper aims to elaborate the method and algorithm for the analysis of the influence of temperature on back electromotive force (BEMF) waveforms in a line start permanent magnet synchronous motor (LSPMSM). The paper presents a finite element analysis of temperature influence on BEMF and back electromotive coefficient in a LSPMSM. In this paper, a two-dimensional field model of coupled electromagnetic and thermal phenomena in the LSPMSM was presented. The influence of temperature on magnetic properties of the permanent magnets as well as on electric and thermal properties of the materials has been taken into account. Simulation results have been compared to measurements. The selected results have been presented and discussed. The simulations results are compared with measurements to confirm the adequacy of this approach to the analysis of coupled electromagnetic-thermal problems. The paper offers appropriate author’s software for the transient and steady-state analysis of coupled electromagnetic and thermal problems in LSPMS motor.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-03-30
      DOI: 10.1108/COMPEL-07-2021-0228
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • An optimization-based methodology to design waveguides with metamaterial
           walls

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      Authors: Ayoub Bellouch , Amine El Alami , Frederic Messine , Nathalie Raveu
      Abstract: The purpose of this sudy is to provide a complete optimization-based methodology to design waveguides with metamaterial walls. The present methodology is based on optimization. Indeed, the inverse problems of design are formulated as nonlinear black-box optimization problems with constraints. Two inequality black-box constraints are taken into account as penalized terms that are added to the objective function when the constraints are not satisfied. The numerical steps are done by using a finite element method solver (GetDP). Thus, different optimization software are tested to solve the nonlinear black-box optimization problems such as IPOPT, NLOPT and NOMAD from the Opti ToolBox in MatLab. In this work, a methodology to design waveguides with metamaterial walls is proposed. The aim is to solve an inverse problem to find the best design where the electric field cartography is the closest to an imposed one. The present methodology is applied to solve inverse problems of design and satisfactory results were provided by the three solvers IPOPT, NLOPT and NOMAD. Those numerical experiments show that NOMAD is the most efficient method to optimize the design of those cylindrical waveguide structures with metamaterial walls. The model is set to find solutions using a specific pattern of metamaterials. This is promising to take those geometries as variables of the optimization problems. Moreover, in this exploratory work, no constraint on the fabrication limits has been taken into account. The originality is to formulate design problems of waveguide with metamaterial walls into optimization problems. These optimization problems are difficult to solve because the objective function and two inequality constraints are computed via a numerical simulation code based on finite element methods. Thus, an original approach based on penalization is implemented and three optimization software are used. Hence, the authors propose an optimization-based methodology and apply to solve two inverse problems of design.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-03-30
      DOI: 10.1108/COMPEL-11-2021-0421
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Design and test of an open portable MRI system

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      Authors: Simon Chauviere , Lamia Belguerras , Thierry Lubin , Smail Mezani
      Abstract: The purpose of this paper is the design study and realisation of portable low-field open MRI system. The design of the magnetic resonance imaging (MRI) system is based on an optimization study using a genetic algorithm. Non-linear two-dimensional and three-dimensional numerical electromagnetic models are developed and inserted in the optimization environment. The results are found to be consistent with those issued from fully experimental tests. The static field produced by the device is 0.295 T with a homogeneity of 2.8% (28,000 ppm) over 100 mm diameter sphere volume. The z-axis gradient coils are capable of generating switching gradients with an amplitude of 8 mT/m and a frequency of 1.2 kHz. Our system is an open portable MRI which can be used in an ambulance. The open topology permits an easy access into the lateral sides when a surgery using surgical instrument with video feedback is needed.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-03-29
      DOI: 10.1108/COMPEL-11-2021-0436
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • A fractional-order equivalent model for characterizing the interelectrode
           capacitance of MOSFETs

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      Authors: Yi Huang , Xi Chen
      Abstract: This paper aims to characterize the relationship between the interelectrode capacitance (C) of metal-oxide-semiconductor field-effect transistors (MOSFETs) and the applied bias voltage (V) by a fractional-order equivalent model. A Riemann–Liouville-type fractional-order equivalent model is proposed for the C–V characteristic of MOSFETs, which is based on the mathematical relationship between fractional calculus and the semiconductor physical model for the interelectrode capacitance of metal oxide semiconductor structure. The C–V characteristic data of an N-channel MOSFET are obtained by Silvaco TCAD simulation. A differential evolution-based offline scheme is exploited for the parameter identification of the proposed model. According to the results of theoretical analysis, mathematical derivation, simulation and comparison, this paper illustrates that, along with the variation of bias voltage applied, the interelectrode capacitance (C) of MOSFETs performs a fractional-order characteristic. This work uncovers the fractional-order characteristic of MOSFETs’ interelectrode capacitance. By the proposed model, the influence of doping concentration on the gate leakage parasitic capacitance of MOSFETs can be revealed. In the pre-defined doping concentration range, the relative error of the proposed model is less than 5% for the description of C–V characteristics of metal-oxide-semiconductor field-effect transistors (MOSFETs). Compared to some existing models, the proposed model has advantages in both model accuracy and model complexity, and the variation of model parameters can directly reflect the relationship between the characteristics of MOSFETs and the doping concentration of materials. Accordingly, the proposed model can be used for the microcosmic mechanism analysis of MOSFETs. The results of the analysis produce evidence for the widespread existence of fractional-order characteristics in the physical world.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-03-24
      DOI: 10.1108/COMPEL-10-2021-0375
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • A new approach for optimal photovoltaic resources in distribution networks
           with reconfiguration based on L_∞

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      Authors: Hussein Mohammed Badr , Ramzy Salim Ali , Jawad Radhi Mahmood
      Abstract: In the vast majority of published papers, the optimal allocation of photovoltaic distributed generation (PVDG) units and reconfiguration problems are proposed along with the number of PVDG used in the simulation. However, optimisation without selecting the number of PVDG units installed in the distribution grid is insufficient to achieve a better operational performance of power systems. Moreover, multi-objective installation of PVDG units and reconfiguration aims to simultaneously relieve congestion problems, improve voltage profile and minimise the active and reactive power losses. Therefore, this paper aims to propose a new modified camel algorithm (NMCA) to solve multi-objective problems considering radial distribution system to achieve secure and stable operation of electric power system with good performance. In this paper, the decision variables include the location and size of PVDG units with specific rang to determine the number of PVDG units needed to install and open network lines determined using NMCA based on the L_∞ technique. This also satisfies the operating and radial constraints. Furthermore, a benchmark comparison with different well known optimisation algorithms has been made to confirm the solutions. Finally, an analysis of the findings was conducted, and the feasibility of solutions was fully verified and discussed. Two test systems – the institute of electrical and electronics engineers (IEEE) 33-bus and IEEE 69-bus, were used to examine the accuracy and effectiveness of the proposed algorithm. The findings obtained amply proved the efficiency and superiority of the NMCA algorithm over the other different optimisation algorithms. The proposed approach is applied to solve the installation PVDG unit’s problem and reconfiguration problem in the radial distribution system, satisfying the operating and radial constraints. Also, it minimises active and reactive power losses and improves voltage profile.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-03-24
      DOI: 10.1108/COMPEL-10-2021-0378
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Plasma monopole antenna array

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      Authors: Athanasios Papadimopoulos , Alessio Di Iorio
      Abstract: This study aims to investigate different configurations of plasma antenna arrays and multiple combinations based on whether the plasma dischargers are set ON or OFF, to assess the coupling, interference and overall performance of these plasma antenna arrays. In this paper, the authors investigate the operation and performance of the combined use of sets of antennas and plasma antenna elements in plasma monopole antenna arrays. The authors find that there can be significant modifications of the plasma antenna arrays’ gain and pattern in multiple ways, merely by switching different combinations of plasma columns ON and OFF. High-density plasma antenna arrays have been examined in this paper and it has been shown that they are capable of reaching high antenna gain. Moreover, the overall antenna array’s gain and pattern can be considerably transformed in multiple ways by turning ON and OFF different combinations of plasma antenna elements. Finally, the electromagnetic coupling and interference coming from these plasma antennas can be greatly reduced.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-03-16
      DOI: 10.1108/COMPEL-10-2021-0387
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Load frequency control based on an improved Chimp optimization algorithm
           using adaptive weight strategy

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      Authors: Ranjitha K. , Sivakumar P. , Monica M.
      Abstract: This study aims to implement an improved version of the Chimp algorithm (IChimp) for load frequency control (LFC) of power system. This work was adopted by IChimp to optimize proportional integral derivative (PID) controller parameters used for the LFC of a two area interconnected thermal system. The supremacy of proposed IChimp tuned PID controller over Chimp optimization, direct synthesis-based PID controller, internal model controller tuned PID controller and recent algorithm based PID controller was demonstrated. IChimp has good convergence and better search ability. The IChimp optimized PID controller is the proposed controlling method, which ensured better performance in terms of converging behaviour, optimizing controller gains and steady-state response.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-03-15
      DOI: 10.1108/COMPEL-07-2021-0231
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Heuristic optimization applied to ANN training for predicting renewable
           energy sources production

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      Authors: Gianmarco Lorenti , Ivan Mariuzzo , Francesco Moraglio , Maurizio Repetto
      Abstract: This paper aims to compare stochastic gradient method used for neural network training with global optimizer without use of gradient information, in particular differential evolution. This contribute shows the application of heuristic optimization algorithms to the training phase of artificial neural network whose aim is to predict renewable power production as function of environmental variables such as solar irradiance and temperature. The training problem is cast as the minimization of a cost function whose degrees of freedom are the parameters of the neural network. A differential evolution algorithm is substituted to the more usual gradient-based minimization procedure, and the comparison of their performances is presented. The two procedures based on stochastic gradient and differential evolution reach the same results being the gradient based moderately quicker in convergence but with a lower value of reliability, as a significant number of runs do not reach convergence. The approach has been applied to two forecasting problems and, even if results are encouraging, the need for extend the approach to other problems is needed. The new approach could open the training of neural network to more stable and general methods, exploiting the potentialities of parallel computing. To the best of the authors’ knowledge, the research presented is fully original for the part regarding the neural network training with differential evolution.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-03-15
      DOI: 10.1108/COMPEL-11-2021-0420
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Finite element analysis and design of beam steering devices with global
           control

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      Authors: Osama Alkhateeb , A.N.M. Shahriyar Hossain , Igor Tsukerman , Nathan Ida
      Abstract: This paper aims to design metaguide- or metasurface-based compact inexpensive beam-steering devices, which play an important role in modern cellular networks, radar imaging and satellite communication. This paper uses finite element analysis to study, design and optimize arrays of resonating elements as beam steering devices. The first set of such devices involves metamaterial-based apertures fed by a waveguide, tunable via the permittivity of the host material. In the second approach, dynamic beam steering is effected by alternating between two or more waveguide feeds. Particular examples show how the direction of the main lobe of the radiated beam can be reliably switched by approximately 30° in one of the quadrants by changing a single global control parameter within a very reasonable range. The findings pave the way for the design and fabrication of inexpensive compact beam steering devices. This study anticipates that the proposed designs can be further improved and fine-tuned using “heavy duty” optimization packages. In many published designs of similar beam-steering devices, the radiation pattern of an array of resonating elements is controlled by complex circuitry, so that each radiating element is tuned separately. In contrast with these existing approaches, the designs rely just on a simple global control parameter.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-03-11
      DOI: 10.1108/COMPEL-08-2021-0291
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Optimal shape design of a class of permanent magnet motors in a
           multiple-objectives context

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      Authors: Paolo Di Barba , Maria Evelina Mognaschi , Lidija Petkovska , Goga Vladimir Cvetkovski
      Abstract: This paper aims to deal with the optimal shape design of a class of permanent magnet motors by minimizing multiple objectives according to an original interpretation of Pareto optimality. The proposed method solves a many-objective problems characterized by five objective functions and five design variables with evolution strategy algorithms, classically used for single- and multi-objective (two objective functions) optimization problems. Two approaches are proposed in the paper: the All-Objectives (AO) and the Many-Objectives (MO) optimization approach. The former is based on a single-objective optimization of a preference function, i.e. a normalized weighted sum. In contrast, in the MO a multi-objective optimization algorithm is applied to the minimization of a weight-free preference function and simultaneously to a maximization of the distance of the current solution from the prototype. The optimizations are based on an equivalent circuit model of the Permanent Magnet (PM) motor, but the results are assessed by means of finite element analyses (FEAs). An extensive study of the solutions obtained by means of the different optimization approaches is provided by means of post-processing analyses. Both the approaches find non-dominated solutions with respect to the prototype that are substantially improving the initial solution. The points of strength along with the weakness points of each solution with respect to the prototype are analysed in depth. The paper gives a good guide to the designers of electric motors, focussed on a shape design optimization. Considering simultaneously five objective functions in an automated optimal design procedure is challenging. The proposed approach, based on a well-known and established optimization algorithm, but exploiting a new concept of degree of conflict, can lead to new results in the field of automated optimal design in a many-objective context.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-03-07
      DOI: 10.1108/COMPEL-10-2021-0394
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Neural network inverse model for multi-band unequal Wilkinson power
           divider

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      Authors: Tarek Sallam , Ahmed M. Attiya
      Abstract: The purpose of this paper is to build a neural network (NN) inverse model for the multi-band unequal-power Wilkinson power divider (WPD). Because closed-form expressions of the inverse input–output relationship do not exist, the NN becomes an appropriate choice, because it can be trained to learn from the data in inverse modeling. The design parameters of WPD are the characteristic impedances, lengths of the transmission line sections and the isolation resistors. The design equations used to train the NN inverse model are based on the even–odd mode analysis. An inverse model of a multi-band unequal WPD using NNs is presented. In inverse modeling of a microwave component, the inputs to the model are the required electrical parameters such as reflection coefficients, and the outputs of the model are the geometrical or the physical parameters. For verification purposes, a quad-band WPD and a penta-band WPD are designed. The results of the full-wave simulations verify the validity of the design procedure. The resulting NN model outperforms traditional time-consuming optimization procedures in terms of computation time with acceptable accuracy. The designed WPDs using NN are implemented by microstrip lines and verified by using full-wave analysis based on high-frequency structure simulator (HFSS). The results of the microstrip WPDs have good agreements with the corresponding results obtained by using ideal transmission line sections. The associated time-consuming procedure and computational burden in realizing WPD through optimization are major disadvantages; needless to mention the substantial increase in optimization time because of the multi-band design. NNs are one of the best candidates in addressing the abovementioned challenges, owing to their ability to process the interrelation between electrical and geometrical/physical characteristics of the WPD in a superfast manner.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-03-04
      DOI: 10.1108/COMPEL-12-2021-0501
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • A novel multi-material topology optimization method for permanent magnet
           assisted synchronous reluctance motors

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      Authors: Yuki Hidaka
      Abstract: The purpose of this paper is to develop a multi-material topology optimization method for permanent magnet-assisted synchronous reluctance motors. In the proposed method, the optimization procedure consists of two steps. In the first step, the entire rotor area was selected for the design region and the distribution of the core and air materials was optimized. In the second step, the design region was limited to the air region of the former solution and the distribution of magnets and cores or magnets and air was optimized. Because of the two-step process of the proposed method, the design parameters can be reduced compared to the conventional method. As a result, this study can prevent the solution space from becoming more complex and superior solutions can be founded effectively. Since limited case study is denoted in this paper, much more case studies, for example, three-dimensional optimization problems, are needed to be discussed. The optimal solutions obtained by the proposed method have a smaller magnet volume and higher average torque than that of the conventional method. In the proposed methods, optimization methodology, which consists of two-steps process, is differed from the conventional method.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-03-02
      DOI: 10.1108/COMPEL-08-2021-0285
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Subdomain modeling of linear hybrid excited flux switching machine

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      Authors: Basharat Ullah , Faisal Khan , Muhammad Qasim
      Abstract: This paper aims to develop an analytical approach to validate the finite element analysis (FEA) results. FEA itself is a powerful tool to evaluate the performance of electrical machines but takes more time and requires more drive storage. To overcome this issue, subdomain modeling (SDM) is used for the proposed machine. SDM is developed to validate the electromagnetic performance of a new linear hybrid excited flux switching machine (LHEFSM) with ferrite magnets. In SDM, the problem is divided into different physical regions called subdomains. Maxwell's governing equation is solved analytically for each region, where the magnetic flux density (MFD) is generated. From the generated MFD, x and y components are calculated, which are then used to find the useful force along the x-axis. FEA validates the developed SDM via JMAG v. 20.1. The results obtained show excellent agreement with an accuracy of 95.13%. The proposed LHEFSM is developed for long stroke applications like electric trains. The proposed LHEFSM uses low-cost ferrite magnets with DC excitation, which offers better flux regulation capability with improved electromagnetic performance. Moreover, the developed SDM reduces drive storage and computational time by modeling different parts of the machine.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-02-28
      DOI: 10.1108/COMPEL-07-2021-0260
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • An adaptive method for calculation of iron losses in switched reluctance
           

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      Authors: Ali Jamali Fard , Mojtaba Mirsalim
      Abstract: This paper aims to present an adaptive method based on finite element analysis to calculate iron losses in switched reluctance motors (SRMs). Calculation of iron losses by analytical formulas has limited accuracy. On the other hand, its estimation in rotating electrical machines through fully dynamic simulations with a fine time-step is time-consuming. However, in the initial design process, a quick and sufficiently accurate method, i.e. a value close to that of iron losses, is always welcome. The method presented in this paper is a semi-analytical approach. The main problem is that iron losses depend on d B/d t. Therefore, the accuracy of the calculation of iron losses depends on the accuracy of the calculation of the first derivative of the flux density waveform. When adopting a magnetostatic model to estimate the iron losses, an important question arises: by how many magnetostatic simulations can the iron losses be estimated within the desired accuracy' In the proposed algorithm, the aim is not to accurately calculate the value of iron losses in SRMs. The objective is to find a numerical error criterion to calculate iron losses in SRMs with a minimum number of magnetostatic simulations. A finite element solver is developed by authors in MATLAB to solve the 2 D nonlinear magnetostatic problem using the Newton–Raphson method. A parametric program is developed to create geometry and mesh. The proposed method is implemented in MATLAB using the developed solver. Counterpart simulations are done in the ANSYS Maxwell software to validate the accuracy of the results generated by the developed solver. The performance of the proposed method is studied on a 12/8 (500 W) SRM. Three scenarios are studied. The first one is the calculation of iron losses by uniform refinement, and the second one is by adaptive refinement, and the last one is by adaptive refinement started by particular initial points (switching points). According to the results, the proposed method substantially reduces the number of magnetostatic simulations without sacrificing accuracy. The main novelty of this paper is introducing an error criterion to find the minimum number of magnetostatic simulations that are needed to calculate iron losses with the desired accuracy.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-02-17
      DOI: 10.1108/COMPEL-07-2021-0251
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Probabilistic weighted voting model using multiple machine learning
           methods for fault detection and classification

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      Authors: Fevzeddin Ülker , Ahmet Küçüker
      Abstract: The individual machine learning methods used for fault detection and classification have accuracy performance at a certain level. A combined learning model composed of different base classifiers rather than an individual machine learning model is introduced to ensure diversity. In this way, this study aims to improve the generalization capability of fault detection and classification scheme. This study presents a probabilistic weighted voting model (PWVM) with multiple learning models for fault detection and classification. The working principle of this study’s proposed model relies on weight selection and per-class possibilities corresponding to predictions of base classifiers. Moreover, it can improve the power of the prediction model and cope with imbalanced class distribution through validation metrics and F-score. The performance of the proposed PWVM was better than the performance of the individual machine learning methods. Besides, the proposed voting model’s performance was compared with different voting mechanisms involving weighted and unweighted voting models. It can be seen from the results that the presented model is superior to voting mechanisms. The performance results revealed PWVM has a powerful predictive model even in noisy conditions. This study determines the optimal model from among voting models with the prioritization method on data sets partitioned different ratios. The obtained results with statistical analysis verified the validity of the proposed model. Besides, the comparative results from different benchmark data sets verified the effectiveness and robustness of this study’s proposed model. The contribution of this study is that PWVM is an ensemble model with outstanding generalization capability. To the best of the authors’ knowledge, no study has been performed using a PWVM composed of multiple classifiers to detect no-faulted/faulted cases and classify faulted phases.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-02-16
      DOI: 10.1108/COMPEL-06-2021-0200
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Conformable fractional order controller design and optimization for
           sensorless control of induction motor

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      Authors: Erdem Ilten
      Abstract: In recent years, use of sensorless control methods for electrical motor-based variable speed drive systems has been increasing rapidly to compensate the increasing costs in industrial systems. Also, use of induction motors is popular for a long time to decrease the cost of these industrial systems. This study aims to design an effective controller to improve the sensorless speed control performance of induction motor. To achieve this, a conformable fractional order proportional integral (CFOPI) controller is designed. The system is modeled based on small signal analysis by using the input–output data, experimentally. To do this, system identification toolbox of Matlab is used. The proposed controller is established on conformable fractional integral approach proposed by Khalil et al. (2014). CFOPI controller coefficients are optimized using particle swarm optimization method on the created small signal-based simulation model of the system to minimize the integral time absolute error. To prove the success of the proposed method, a traditional fractional order proportional integral (TFOPI) controller is tested under the same experimental system with the CFOPI controller. TFOPI and CFOPI controllers are tested with the optimum parameters. Reference and actual speed trends are obtained for both methods. In induction motor start-up test, settling-times are measured as 8.73 and 8.44 s and steady-state oscillations are 2.66% and 0% (almost) for TFOPI and CFOPI controllers, respectively. In variable referenced speed tracking test, CFOPI performs well at all speed levels, while TFOPI fails to reach the reference speed at most speed levels. Proposed CFOPI control method can be easily implemented in industrial systems, thanks to its simple algorithm. digital signal peripheral interface controller (dsPIC) based driver circuit with designed CFOPI controller used in this study can be applied directly to industrial systems such as elevators, conveyors, cranes and drills. Moreover, it can improve the performance of induction motor-based variable speed drive systems. The proposed method provides robust performance for induction motor used in control systems. Additionally, it does this by using less complex algorithm written on the processors according to the traditional fractional order controllers.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-02-14
      DOI: 10.1108/COMPEL-09-2021-0334
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • 3D fast analytical computation of a permanent magnets axial coupler

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      Authors: Aziz Zerioul , Larbi Hadjout , Youcef Ouazir , Smail Mezani , Mohammed Messadi
      Abstract: The purpose of this paper is to develop a new and fast three-dimensional (3D) analytical model to study a synchronous axial magnetic coupling with rectangular shaped magnets. This model takes into account edge and curvature 3D effects. This paper firstly introduces a 3D analytical model for an axial coupler with sector shaped permanent magnet (PM) based on magnetic scalar potential formulation in cylindrical coordinates. The magnetic field in PM, air gap and iron disks is computed by solving Laplace’s and Poisson’s partial differential equation. This solution is then used to compute the field in rectangular shaped magnets. To do so, the adopted approach consists to divide the rectangular magnet into sector radial slices each of which the 3D model allows the determination of the magnetic field distribution. The results obtained by the proposed 3D analytical model are validated through 3D finite element computations. Furthermore, a prototype axial magnetic coupler has been constructed so air gap flux density and static torque measurements are compared to the analytical predictions. The results obtained by the analytical model show the effectiveness of the proposed geometry transformation approach. The developed model takes into account all the 3D effects without needing any correction factor. The developed method provides an efficient and rapid tool for evaluating the influence of geometric and physical parameters of a synchronous magnetic coupling as part of a design optimization process. The developed method provides an efficient and rapid tool for evaluating the influence of geometric and physical parameters of a synchronous magnetic coupling as part of a design optimization process. A new and fast 3D analytical model, to improve the computation of the electromagnetic torque developed by a synchronous magnetic coupler with rectangular shaped magnets, has been developed. The proposed approach is really effective as it leads to consistent results when compared to 3D finite element method ones without any need for correction factor.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-02-14
      DOI: 10.1108/COMPEL-11-2021-0429
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Measurement and approximation by simulation of the instantaneous breakdown
           voltage of lightning discharge in the presence of protection

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      Authors: Djazia Khelil , Slimane Bouazabia , Pantelis N. Mikropoulos
      Abstract: The paper aims to estimate the instantaneous breakdown voltage of the lightning discharge from simulated figures in an energized rod-plane configuration protected by a lightning rod. The same configuration of electrodes has been the subject of experimental investigations for the measurement of the instantaneous breakdown voltage using oscillographic monitoring. This study validates the simulation model by making a comparison with experimentation and involves the role of the inception field of the upward discharge in the propagation of this last one. The research methodology is based on the development of a fractal lightning protection model based on real physical conditions of the discharge propagation, such as the downward discharge and the upward one emanating from protection. The voltage drop and the randomness character of the lightning discharge are also taken into account. The electrical field is an important parameter in discharge development; it is considered in this work at each step of the discharge propagation by the finite element method. The instantaneous breakdown voltage is measured and estimated by both empirical equations and simulated figures of lightning discharge The established model that allows estimating the instantaneous breakdown voltage from simulated discharges and empirical equations gives results in a good agreement with experimentation. The involvement of the upward discharge inception field emanating from the lightning rod in the evolution of electrical discharge is illustrated. The work presented in this paper aims to develop a new fractal lightning protection model taking into consideration physical phenomena intervening in the development of the lightning discharge. The originality of this work consists of the combination between fractals modelling of the electrical discharge and the protection against lightning, in addition, to use one of the characteristics of the electrical discharge, which is the instantaneous breakdown voltage, to prove the importance of the inception field emanating from the upward discharge in the propagation criterion of this last one.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-02-10
      DOI: 10.1108/COMPEL-11-2021-0442
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • A novel hybrid particle swarm optimization rat search algorithm for
           parameter estimation of solar PV and fuel cell model

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      Authors: Manish Kumar Singla , Parag Nijhawan , Amandeep Singh Oberoi
      Abstract: The purpose of the proposed hybrid method aims to increase population efficiency, and a local search is used to further improve the value of the global best solution. An experimental observation suggests that the model’s statistical outcomes are more aligned with the real-time experimental findings. A novel metaheuristic efficient hybrid algorithm, i.e. hybrid particle swarm optimization rat search algorithm, is introduced and applied for parameter extraction of hybrid energy system. This proposed hybrid method rules out the chances of local minima, hence enhancing the precision of the parametric estimation. The parameter extraction and error is calculated for the solar photovoltaic (PV)–fuel cell system using the proposed algorithm. Nonparametric statistical tests are also conducted to indicate the findings of the outcome parameters using various metaheuristic algorithms. The proposed algorithm is better than the rest of the compared algorithms in the study. The authors proposed a novel algorithm, and this proposed algorithm is implemented on hybrid solar PV and fuel cell-based system for parameter extraction. The nonparametric test results clearly suggest that the proposed algorithm is far more effective for parameter estimation of the test system.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-02-08
      DOI: 10.1108/COMPEL-07-2021-0257
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Electrical power components decomposition of periodic polyharmonic current

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      Authors: Oleksii V. Bialobrzheskyi , Dmytro Rod`Kin , Andrii Gladyr
      Abstract: At the current stage of electrical technology development, it is relevant to take into account the quality of electrical energy. It can be implemented if an assessed energy quality indicator is available. The amount of electrical energy is determined by active power, which is transmitted over a certain time period. In some cases, reactive power is included in the metering system. The distortion power is justifiably criticized and is not taken into account. The purpose of this paper consists in the substantiation of the indicator of the distortion of the periodic polyharmonic current electrical energy power, by separating from the instantaneous power such harmonics, which formed by same frequencies current and voltage harmonics. Using the method of calculating linear polyharmonic current circuits, the following quantities are identified in instantaneous power: active, reactive and apparent powers of each harmonic. These components are known from references as canonical. By the method of instantaneous power harmonic analysis, the components formed by current and voltage harmonics of the same frequency and different frequencies are distinguished. The RMS value of the instantaneous power due to current and voltage harmonics of different frequencies is justified in the work. This quantity allows you to distinguish the instantaneous power distortion level in comparison with the existing quantity. The results can be used to assess the level of instantaneous power distortion level in commercial and technical metering systems. The definition of instantaneous power distortion by extracting the canonical components from it and determining the root mean square value of the remainder is proposed.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-02-01
      DOI: 10.1108/COMPEL-10-2021-0397
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Mathematical modeling of the electric field in the planar and coaxial
           dielectric barrier discharge reactor in water treatment application

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      Authors: Masoume Amirbande , Abolfazl Vahedi
      Abstract: To design a pulse power water treatment system, it is necessary to design a reactor optimally. One of the most essential types of reactors used in water treatment is the dielectric barrier discharge (DBD) reactor. The purpose of this paper is to model the electric field in the two types of planar and coaxial reactors to have an accurate analytical formula for using in the optimal design according to the required electric field of the treatment. The method proposed in this paper focuses on the voltage of different areas in the reactor and different boundary conditions to obtain the surface charge density. In this regard, parameters of the dielectric and treated material, as well as the reactor dimension, have been affected in the equations. To confirm the analytical results, the finite element method simulation has been performed, and it shows the accuracy of this method. The exact analytical equation of the electric field is found within the discharge zone of the planar and coaxial DBD reactors. These equations can predict the values of different parameters of the reactor required to purify the material before each design and it does not even require simulation. The electric field formula presented in this paper can allow the manufacturers of pulse power water treatment systems to optimize their design easily, cost-effectively and in less time. Also, the formulas provided are completely general and remain effective for all materials.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-01-31
      DOI: 10.1108/COMPEL-08-2021-0309
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Analysis of methods and approaches of the electromagnetic calculation of
           induction machines regarding their use to solve multiphysical problems

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      Authors: Martin Marco Nell , Marius Franck , Kay Hameyer
      Abstract: For the electromagnetic simulation of electrical machines, models with different ranges of values, levels of detail and accuracies are used. In this paper, numerical and two analytical models of an induction machine (IM) are analysed with respect to these aspects. The purpose of the paper is to use these analyses to discuss the suitability of the models for the simulation of various physical quantities of an IM. An exemplary IM is simulated using the two-dimensional numerical finite element method, an analytical harmonic wave model (HWM) and an extended HWM. The simulation results are analyzed among themselves in terms of their level of detail and accuracy. Furthermore, the results of operating map simulations are compared with measured operating maps of the exemplary machine, and the accuracy of the simulation approaches is discussed in the context of measurement deviations and uncertainties. The difference in the accuracy of the machine models depends on the physical quantity of interest. Therefore, the choice of the simulation method depends on the nature of the problem and the expected range of results. For modeling global machine quantities, such as mean torque or losses, analytical methods such as the HWM s are sufficient in many applications because the simulation results are within the range of measurement accuracy of current measurement systems. Analytical methods are also suitable for local flux density curves under certain conditions. However, for the simulation of the influence of local physical effects on the machine behavior and of temporally highly resolved quantities in saturated operating points, the accuracy of the analytical models decreases and the use of the finite element method becomes necessary. In this paper, an extension of the HWM is used to calculate the IM, which, in contrast to the HWM, models the saturation. Furthermore, the simulation results of the different electromagnetic IM models are put into the context of the uncertainty of a measurement of several identical IMs.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-01-27
      DOI: 10.1108/COMPEL-07-2021-0249
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Noise analysis of electrical circuits on fractal set

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      Authors: Rawid Banchuin
      Abstract: The purpose of this study is to originally present noise analysis of electrical circuits defined on fractal set. The fractal integrodifferential equations of resistor-inductor, resistor-capacitor, inductor-capacitor and resistor-inductor-capacitor circuits subjected to zero mean additive white Gaussian noise defined on fractal set have been formulated. The fractal time component has also been considered. The closed form expressions for crucial stochastic parameters of circuit responses have been derived from these equations. Numerical simulations of power spectral densities based on the derived autocorrelation functions have been performed. A comparison with those without fractal time component has been made. We have found that the Hausdorff dimension of the middle b Cantor set strongly affects the power spectral densities; thus, the average powers of noise induced circuit responses and the inclusion of fractal time component causes significantly different analysis results besides the physical measurability of electrical quantities. For the first time, the noise analysis of electrical circuit on fractal set has been performed. This is also the very first time that the fractal time component has been included in the fractal calculus-based circuit analysis.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-01-26
      DOI: 10.1108/COMPEL-08-2021-0269
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Transient modeling and analysis of fractional-order resonant very high
           frequency boost converter

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      Authors: Xinyi Jiang , Yanfeng Chen , Bo Zhang , Dongyuan Qiu
      Abstract: This paper aims to present a simplified method to analyze the transient characteristics of a fractional-order very high frequency (VHF) resonant boost converter. The transient analytical solutions of state variables obtained by this method could be used as a guide for parameter design and circuit optimization. The VHF converter is decoupled into a simplified equivalent circuit model and described by the differential equation. The solution of the simplified equivalent circuit model is taken as the main oscillation component of the transient state variable. And the equivalent small parameter method (ESPM) and Kalman filter technology are used to solve the differential equation of the converter to obtain the steady-state ripple component. Then, by superimposing the abovementioned two parts, the approximate transient analytical solution can be acquired. Finally, the influence of the fractional order of the energy storage elements on the transient process of the converter is discussed. The results from the proposed method agree well with those from simulations, which indicates that the proposed method can effectively analyze the transient characteristic of the fractional-order VHF converter, and the analytical solution derived from the proposed mathematical model shows sufficient accuracy. This paper proposes for the first time a method to analyze the transient characteristics of a fractional-order VHF resonant boost converter. By combining the main oscillated solution derived from the simplified equivalent circuit model with the steady-state solution based on ESPM, this method can greatly reduce the computation amount to estimate the transient solution. In addition, the discussion on the order of fractional calculus of energy storage components can provide an auxiliary guidance for the selection of circuit parameters and the study of stability.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-01-26
      DOI: 10.1108/COMPEL-08-2021-0313
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Finite element models of dynamic-WPTS: a field-circuit approach

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      Authors: Manuele Bertoluzzo , Paolo Di Barba , Michele Forzan , Maria Evelina Mognaschi , Elisabetta Sieni
      Abstract: The paper aims to propose a a field-circuit method for investigating the magnetic behavior of a wireless power transfer system (WPTS) for the charge of batteries of electric vehicles. In particular, a 3D model for finite element analysis (FEA) for the field simulation of a WPTS is developed. Specifically, the effects of aluminum shield and steel layer, representing the car frame, on the self and mutual inductances are investigated. An equivalent electric circuit is then built, and the relevant lumped parameters are identified by means of the FEAs. The finite element model is used to evaluate self and mutual inductances in several transmitting-receiving coil configurations and relative positions. In particular, the FEA simulates the aluminum and steel layers as shell elements in a 3D domain. The self and mutual inductance values in the aligned coil case are also used as input parameters in a circuit model to evaluate the onload current. The use of shell elements in FEA substantially reduces the number of mesh elements needed to simulate the eddy currents in the steel and aluminum layer, so putting the ground for low-cost field analysis. Moreover, the FEA gives an accurate computation of the self and mutual inductance to be used in a circuit model, which, in turn, provides a fast update of the onload induced current. To save computational time, the use of 2D shell elements to model thin conductive regions introduces a simplified FEA that could be used in the WPTS simulation. Moreover, the dynamic behavior of WPTS, i.e. the operation when the receiving coil is moving with respect to the transmitting one, is considered. Because of the lumped parameters’ dependence upon the relative positions of the two coils, the proposed method allows identifying the circuit parameters for several configurations so substantially reducing the computational burden.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-01-26
      DOI: 10.1108/COMPEL-10-2021-0403
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • An introduction to the parabolic equation method for electromagnetic wave
           propagation in tunnels

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      Authors: Hafiz Faiz Rasool , Muhammad Ali Qureshi , Abdul Aziz , Zain Ul Abiden Akhtar , Usman Ali Khan
      Abstract: The purpose of this paper is to provide a brief introduction of the finite difference based parabolic equation (PE) modeling to the advanced engineering students and academic researchers. A three-dimensional parabolic equation (3DPE) model is developed from the ground up for modeling wave propagation in the tunnel via a rectangular waveguide structure. A discussion of vector wave equations from Maxwell’s equations followed by the paraxial approximations and finite difference implementation is presented for the beginners. The obtained simulation results are compared with the analytical solution. It is shown that the alternating direction implicit finite difference method (FDM) is more efficient in terms of accuracy, computational time and memory than the explicit FDM. The reader interested in maximum details of individual contributions such as the latest achievements in PE modeling until 2021, basic PE derivation, PE formulation’s approximations, finite difference discretization and implementation of 3DPE, can learn from this paper. For the purpose of this paper, a simple 3DPE formulation is presented. For simplicity, a rectangular waveguide structure is discretized with the finite difference approach as a design problem. Future work could use the PE based FDM to study the possibility of utilization of meteorological techniques, including the effects of backward traveling waves as well as making comparisons with the experimental data. The proposed work is directly applicable to typical problems in the field of tunnel propagation modeling for both national commercial and military applications.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-01-21
      DOI: 10.1108/COMPEL-07-2021-0245
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Electric field simulations of field grading techniques in HVDC cable
           joints

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      Authors: Christoph Jörgens , Markus Clemens
      Abstract: In high voltage direct current cable systems, cable joints are known as the least reliable components due to the use of multiple dielectrics. Resulting from the electric field and temperature depending conductivity of the different dielectrics, field enhancement at critical areas, e.g. triple points, may result in accelerated aging and the failure of the component. To reduce the stress, different field grading techniques are applied. The purpose of this study is to investigate different grading techniques for cable joints. Different shapes of the electrode and a varying nonlinear conductivity of field grading materials (FGM) are used for the simulation of the electric field. Coupled electro-thermal field simulations are applied for different joint geometries, to obtain the stationary electric field. Electric field simulations in cable joint using geometric and nonlinear field grading techniques are shown. Using the geometric field grading, the shape of the stress cone determines the field values in critical areas (triple points). High stress reduction is obtained for a certain curvature of the stress cone. For the nonlinear stress control, materials with a higher conductivity in comparison to the cable and the joint material are used. A field reduction is obtained by increasing the total conductivity. On the other hand, this is also increasing the insulation losses within the total FGM. More applicable is the decrease of the switching field or the increase of nonlinearity, which is only locally increase the conductivity and the insulation losses. Furthermore, simulations results show that an approximately constant field reduction is obtained, if the nonlinearity is above a certain threshold. This study is restricted to a field dependency of FGM only. For impulse voltages, high temperature and electric conductivity values my result in a thermal runaway. Furthermore, only direct current field grading techniques are studied. The field grading of cable joints, using geometric and nonlinear techniques, is analyzed. A comparison between the electric field, by varying the curvature of the ground stress cone or the FGM conductivity constants in a complex joint geometry is novel. With its effect on the electric fields, general requirements for the geometry (geometric field grading) or the values of the FGM constants (nonlinear field grading) are defined to obtain a sufficient field grading.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-01-21
      DOI: 10.1108/COMPEL-10-2021-0382
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • An improved Newton-Raphson based linear power flow method for DC grids
           with dispatchable DGs and ZIP loads

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      Authors: Hongwei Li , Xiao Wang , Junmu Lin , Lei Wu , Tong Liu
      Abstract: This study aims to provide a solution of the power flow calculation for the low-voltage ditrect current power grid. The direct current (DC) power grid is becoming a reliable and economic alternative to millions of residential loads. The power flow (PF) in the DC network has some similarities with the alternative current case, but there are important differences that deserve to be further concerned. Moreover, the dispatchable distributed generators (DGs) in DC network can realize the flexible voltage control based on droop-control or virtual impedance-based methods. Thus, DC PF problems are still required to further study, such as hosting all load types and different DGs. The DC power analysis was explored in this paper, and an improved Newton–Raphson based linear PF method has been proposed. Considering that constant impedance (CR), constant current (CI) and constant power (CP) (ZIP) loads can get close to the practical load level, ZIP load has been merged into the linear PF method. Moreover, DGs are much common and can be easily connected to the DC grid, so V nodes and the dispatchable DG units with droop control have been further taken into account in the proposed method. The performance and advantages of the proposed method are investigated based on the results of the various test systems. The two existing linear models were used to compare with the proposed linear method. The numerical results demonstrate enough accuracy, strong robustness and high computational efficiency of the proposed linear method even in the heavily-loaded conditions and with 10 times the line resistances. The conductance corresponding to each constant resistance load and the equivalent conductance for the dispatchable unit can be directly merged into the self-conductance (diagonal component) of the conductance matrix. The constant current loads and the injection powers from dispatchable DG units can be treated as the current sources in the proposed method. All of those make the PF model much clear and simple. It is capable of offering enough accuracy level, and it is suitable for applications in DC networks that require a large number of repeated PF calculations to optimize the energy flows under different scenarios.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-01-18
      DOI: 10.1108/COMPEL-06-2021-0195
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Cascade controllers design based on model matching in frequency domain for
           stable and integrating processes with time delay

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      Authors: Mohd Atif Siddiqui , Md Nishat Anwar , Shahedul Haque Laskar
      Abstract: This paper aims to present an efficient and simplified proportional-integral/proportional-integral and derivative controller design method for the higher-order stable and integrating processes with time delay in the cascade control structure (CCS). Two approaches based on model matching in the frequency domain have been proposed for tuning the controllers of the CCS. The first approach is based on achieving the desired load disturbance rejection performance, whereas the second approach is proposed to achieve the desired setpoint performance. In both the approaches, matching between the desired model and the closed-loop system with the controller is done at a low-frequency point. Model matching at low-frequency points yields a linear algebraic equation and the solution to these equations yields the controller parameters. Simulations have been conducted on several examples covering high order stable, integrating, double integrating processes with time delay and nonlinear continuous stirred tank reactor. The performance of the proposed scheme has been compared with recently reported work having modified cascade control configurations, sliding mode control, model predictive control and fractional order control. The performance of both the proposed schemes is either better or comparable with the recently reported methods. However, the proposed method based on desired load disturbance rejection performance outperforms among all these schemes. The main advantages of the proposed approaches are that they are directly applicable to any order processes, as they are free from time delay approximation and plant order reduction. In addition to this, the proposed schemes are capable of handling a wide range of different dynamical processes in a unified way.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-01-17
      DOI: 10.1108/COMPEL-06-2021-0185
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Design and lumped parameter magnetic network model of hybrid excited
           consequent pole flux switching machine

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      Authors: Basharat Ullah , Faisal Khan , Bakhtiar Khan , Muhammad Yousuf
      Abstract: The purpose of this paper is to analyze electromagnetic performance and develop an analytical approach to find the suitable coil combination and no-load flux linkage of the proposed hybrid excited consequent pole flux switching machine (HECPFSM) while minimizing the drive storage and computational time which is the main problem in finite element analysis (FEA) tools. First, a new HECPFSM based on conventional consequent pole flux switching permanent machine (FSPM) is proposed, and lumped parameter magnetic network model (LPMNM) is developed for the initial analysis like coil combination and no-load flux linkage. In LPMNM, all the parts of one-third machine are modeled which helps in reduction of drive storage, computational complexity and computational time without affecting the accuracy. Second, self and mutual inductance are calculated in the stator, and dq-axis inductance is calculated using park transformation in the rotor of the proposed machine. Furthermore, on-load performance analysis, like average torque, torque density and efficiency, is done by FEA. The developed LPMNM is validated by FEA via JMAG v. 19.1. The results obtained show good agreement with an accuracy of 96.89%. The proposed HECPFSM is developed for high-speed brushless AC applications like electric vehicle (EV)/hybrid electric vehicle (HEV). The proposed HECPFSM offers better flux regulation capability with enhanced electromagnetic performance as compared to conventional consequent pole FSPM. Moreover, the developed LPMNM reduces drive storage and computational time by modeling one-third of the machine.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-01-05
      DOI: 10.1108/COMPEL-07-2021-0235
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Experimental investigation and comparative study of signal processing
           techniques dedicated for the diagnosis of rotor failures in the induction
           motors

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      Authors: Wissam Dehina , Mohamed Boumehraz , Frédéric Kratz
      Abstract: The purpose of this paper is to propose applications of advanced signal-processing techniques for the diagnosis and detection of rotor fault in an induction machine. Two techniques are used: spectral analysis techniques and time frequency techniques for the diagnosis of an electrical machine. One is based on the power spectral density estimation techniques, such as periodogram and Welch periodogram. The second method is based on Hilbert transform (HT) to extract the envelope for the stator current. Then, this signal is processed via discrete wavelet transform (DWT) for determining the faulty components in the spectrum of the stator current envelope and identifying the eigenvalues of energies (HDWT). First, this paper focused on theoretical development and a comparative study of these signal-processing techniques, which are based on the periodogram, Welch periodogram, HT and the DWT to extract the envelope for the stator current; it is used to compute the energy stored in each decomposition level obtained by the stator current envelope (HDWT). Moreover, the Welch periodogram is applied to obtain the envelope spectrum. The simulation obtained and the experimental validation results of the proposed methods through MATLAB environment show the effectiveness of the proposed approaches with a good accuracy by power spectral density estimation techniques (periodogram and Welch periodogram). Moreover, the faults are manifested through the appearance of new frequencies components, as well as the envelope for the stator current (HT and DWT). This approach is effective for non-stationary and stationary signal to extract useful information for the detection of broken bar fault. The current paper proposes a new diagnosis method for the detection and characterization of broken rotor bars defects early; it is founded primarily on theoretical development, and the comparison is based on the power spectral density technique (periodogram and Welch periodogram) and the computation of the energy stored in each decomposition level (precisely the HT and DWT). Moreover, the Welch periodogram is applied to obtain the envelope spectrum. The main advantages of the proposed techniques increase their reliability and availability.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-01-05
      DOI: 10.1108/COMPEL-08-2019-0321
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Guest editorial: Preface

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      Authors: Oszkár Bíró , Piergiorgio Alotto , David Lowther
      Abstract: Guest editorial: Preface
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-05-10
      DOI: 10.1108/COMPEL-05-2022-601
      Issue No: Vol. 41 , No. 3 (2022)
       
  • Correlating structural complexity and acoustic noise performance of
           electric motors

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      Authors: Issah Ibrahim , Mohammad Hossain Mohammadi , Vahid Ghorbanian , David Lowther
      Abstract: Acoustic noise is a crucial performance index in the design of electrical machines. Due to the challenges associated with modelling a complete motor, the stator is often used to estimate the sound power in the prototyping stage. While this approach greatly reduces lengthy simulations, the actual sound power of the motor may not be known. But, from the acoustic noise standpoint, not much is known about the correlation between the stator and complete motor. This paper, therefore, aims to use the sound pressure levels of the stator and the full motor to investigate the existence of correlations in the interior permanent magnet synchronous motor. A multiphysics simulation framework is proposed to evaluate the sound pressure levels of multiple motor geometries in a given design space. Then, a statistical analysis is performed on the calculated sound pressure levels of each geometry over a selected speed range to compare the correlation strength between the stator and the full model. It was established that the stator and the complete motor model are moderately correlated. As such, a reliance on the stator sound power for design and optimization routines could yield inaccurate results. The main contribution involves the use of statistical tools to study the relationship between sound pressure levels associated with the stator geometry and the complete electric motor by increasing the motor sample size to capture subtle acoustic correlation trends in the design space of the interior permanent magnet synchronous motor.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-03-29
      DOI: 10.1108/COMPEL-03-2021-0094
      Issue No: Vol. 41 , No. 3 (2022)
       
  • Domain decomposition and upscaling technique for metascreens
         This is an Open Access Article Open Access Article

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      Authors: Michael Leumüller , Karl Hollaus , Joachim Schöberl
      Abstract: This paper aims to consider a multiscale electromagnetic wave problem for a housing with a ventilation grill. Using the standard finite element method to discretise the apertures leads to an unduly large number of unknowns. An efficient approach to simulate the multiple scales is introduced. The aim is to significantly reduce the computational costs. A domain decomposition technique with upscaling is applied to cope with the different scales. The idea is to split the domain of computation into an exterior domain and multiple non-overlapping sub-domains. Each sub-domain represents a single aperture and uses the same finite element mesh. The identical mesh of the sub-domains is efficiently exploited by the hybrid discontinuous Galerkin method and a Schur complement which facilitates the transition from fine meshes in the sub-domains to a coarse mesh in the exterior domain. A coarse skeleton grid is used on the interface between the exterior domain and the individual sub-domains to avoid large dense blocks in the finite element discretisation matrix. Applying a Schur complement to the identical discretisation of the sub-domains leads to a method that scales very well with respect to the number of apertures. The error compared to the standard finite element method is negligible and the computational costs are significantly reduced.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-03-16
      DOI: 10.1108/COMPEL-03-2021-0073
      Issue No: Vol. 41 , No. 3 (2022)
       
  • Investigation of electromagnetic wave propagation in the bicomplex 3D-FEM
           using a wavenumber Whitney Hodge operator

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      Authors: Thomas Reum , Hannes Toepfer
      Abstract: The purpose of this paper is to show the applicability of a discrete Hodge operator in the context of the De Rham cohomology to bicomplex-valued electromagnetic wave propagation problems. It was applied in the finite element method (FEM) to get a higher accuracy through conformal discretization. Therewith, merely the primal mesh is needed to discretize the full system of Maxwell equations. At the beginning, the theoretical background is presented. The bicomplex number system is used as a geometrical algebra to describe three-dimensional electromagnetic problems. Because we treat rotational field problems, Whitney edge elements are chosen in the FEM to realize a conformal discretization. Next, numerical simulations regarding practical wave propagation problems are performed and compared with the common FEM approach using the Helmholtz equation. Different field problems of three-dimensional electromagnetic wave propagation are treated to present the merits and shortcomings of the method, which calculates the electric and magnetic field at the same spatial location on a primal mesh. A significant improvement in accuracy is achieved, whereas fewer essential boundary conditions are necessary. Furthermore, no numerical dispersion is observed. A novel Hodge operator, which acts on bicomplex-valued cotangential spaces, is constructed and discretized as an edge-based finite element matrix. The interpretation of the proposed geometrical algebra in the language of the De Rham cohomology leads to a more comprehensive viewpoint than the classical treatment in FEM. The presented paper may motivate researchers to interpret the form of number system as a degree of freedom when modeling physical effects. Several relationships between physical quantities might be inherently implemented in such an algebra.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-02-16
      DOI: 10.1108/COMPEL-03-2021-0078
      Issue No: Vol. 41 , No. 3 (2022)
       
  • Measurement and modeling of effective cable parameters of unshielded
           conductors

         This is an Open Access Article Open Access Article

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      Authors: Karl Hollaus , Susanne Bauer , Michael Leumüller , Christian Türk
      Abstract: Cables are ubiquitous in electronic-based systems. Electromagnetic emission of cables and crosstalk between wires is an important issue in electromagnetic compatibility and is to be minimized in the design phase. To facilitate the design, models of different complexity and accuracy, for instance, circuit models or finite element (FE) simulations, are used. The purpose of this study is to compare transmission line parameters obtained by measurements and simulations. Transmission line parameters were determined by means of measurements in the frequency and time domain and by FE simulations in the frequency domain and compared. Finally, a Spice simulation with lumped elements was performed. The determination of the effective permittivity of insulated wires seems to be a key issue in comparing measurements and simulations. A space decomposition technique for a guided wave on an infinite configuration with constant cross-section has been introduced, where an analytic representation in the direction of propagation is used, and the transversal fields are approximated by FEs.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-02-16
      DOI: 10.1108/COMPEL-03-2021-0098
      Issue No: Vol. 41 , No. 3 (2022)
       
  • Steady state solution of NFC model with nonlinear load using PEEC
         This is an Open Access Article Open Access Article

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      Authors: Samuel Kvasnicka , Thomas Bauernfeind , Paul Baumgartner , Riccardo Torchio
      Abstract: The purpose of this paper is to show that the computation of time-periodic signals for coupled antenna-circuit problems can be substantially accelerated by means of the single shooting method. This allows an efficient analysis of nonlinearly loaded coupled loop antennas for near field communication (NFC) applications. For the modelling of electrically small coupled field-circuit problems, the partial element equivalent circuit (PEEC) method shows to be very efficient. For analysing the circuit-like description of the coupled problem, this paper developed a generalised modified nodal analysis (MNA) and applied it to specific NFC problems. It is shown that the periodic steady state (PSS) solution of the resulting differential-algebraic system can be computed very time efficiently by the single shooting method. A speedup of roughly 114 to conventional transient approaches can be achieved. The proposed approach appears to be an efficient alternative for the computation of time PSS solutions for nonlinear circuit problems coupled with discretised conductive structures, where the homogeneous solution is not of interest. The present paper explores the implementation and application of the shooting method for nonlinearly loaded coupled antenna-circuit problems based on the PEEC method and shows the efficiency of this approach.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-02-01
      DOI: 10.1108/COMPEL-03-2021-0087
      Issue No: Vol. 41 , No. 3 (2022)
       
  • Computation of rotational hysteresis losses by vector Preisach models
           based on rotational operators

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      Authors: Michael Nierla , Manfred Kaltenbacher , Stefan Johann Rupitsch
      Abstract: A major purpose of vector hysteresis models lies in the prediction of power losses under rotating magnetic fields. The well-known vector Preisach model by Mayergoyz has been shown to well predict such power losses at low amplitudes of the applied field. However, in its original form, it fails to predict the reduction of rotational power losses at high fields. In recent years, two variants of a novel vector Preisach model based on rotational operators have been published and investigated with respect to general accuracy and performance. This paper aims to examine the capabilities of the named vector Preisach models in terms of rotational hysteresis loss calculations. In a first step, both variants of the novel rotational operator-based vector Preisach model are tested with respect to their overall capability to prescribe rotational hysteresis losses. Hereby, the direct influence of the model-specific parameters onto the computable losses is investigated. Afterward, it is researched whether there exists an optimized set of parameters for these models that allows the matching of measured rotational hysteresis losses. The theoretical investigations on the influence of the model-specific parameters onto the computable rotational hysteresis losses showed that such losses can be predicted in general and that a variation of these parameters allows to adapt the simulated loss curves in both shape and amplitude. Furthermore, an optimized parameter set for the prediction of the named losses could be retrieved by direct matching of simulated and measured loss curves. Even though the practical applicability and the efficiency of the novel vector Preisach model based on rotational operators has been proven in previous publications, its capabilities to predict rotational hysteresis losses has not been researched so far. This publication does not only show the general possibility to compute such losses with help of the named vector Preisach models but also in addition provides a routine to derive an optimized parameter set, which allows an accurate modeling of actually measured loss curves.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-02-01
      DOI: 10.1108/COMPEL-02-2021-0061
      Issue No: Vol. 41 , No. 3 (2022)
       
  • Enhanced beamforming techniques for cylindrical-substrate microstrip array
           antennas

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      Authors: Christos P. Exadaktylos , Dimitrios I. Karatzidis , Theodoros T. Zygiridis , Nikolaos V. Kantartzis
      Abstract: A class of robust and efficient beamforming methods is developed in this paper for the optimised design of realistic microstrip antennas on arbitrarily curved substrates. More specifically, this paper aims to focus on the formulation of an effective and computationally light beamforming algorithm and its implementation on a novel realistic cylindrical-substrate microstrip array antenna with significantly decreased size, wideband operation and enhanced radiation characteristics. The proposed multi-parametric schemes introduce an efficient null-steering concept, which drastically annihilates the undesired beamformer waveform artefacts, while retaining the real output signal undistorted. In particular, the key objective is the accurate calculation of the appropriate complex feeding weights, required to set nulls along the propagation directions of the unwanted signals and a maximum towards the propagation direction of the desired incoming signal. The featured technique, combined with a modified finite element method, is applied to the design of a new family of cylindrical-substrate microstrip array antennas. Numerical results, mainly concerning customisable three-dimensional radiation patterns and attributes, certify the merits of the algorithm and its limited system demands. The introduced beamforming algorithms are applied to a variety of different inputs (desired radiation patterns), which indicate that the designed cylindrical-substrate antenna overwhelms existing designs in terms of computational cost for the beamforming algorithm, while retaining acceptable values for radiation characteristics, such as gain, directivity and side-lobe suppression. In this manner, the effectiveness of the prior methodology and the benefits of this newly shaped array antenna are comprehensively revealed and substantiated. Rigorous beamforming techniques in conjunction with a class of contemporary array antennas are developed for potential use in high-end communication systems, such as 5G configurations. The proposed cylindrical-shaped structures are systematically designed, with an emphasis on space efficiency and wideband radiation effectiveness to offer fully adjustable setups. To this aim, the cylindrical-substrate microstrip antenna, because of its inherent azimuthal symmetry and confined overall dimensions, provides reliable operation and promising performance.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-01-24
      DOI: 10.1108/COMPEL-03-2021-0089
      Issue No: Vol. 41 , No. 3 (2022)
       
  • Finite-difference wave-propagation models for dispersive media: impact of
           space-time discretization

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      Authors: Theodoros Zygiridis , Nikolaos Kantartzis
      Abstract: The computational accuracy and performance of finite-difference time-domain (FDTD) methods are affected by the implementation of approximating derivative formulae in diverse ways. This study aims to focus on FDTD models featuring material dispersion with negligible losses and investigates two specific aspects that, until today, are usually examined in the context of non-dispersive media only. These aspects pertain to certain abnormal characteristics of coarsely resolved electromagnetic waves and the selection of the proper time-step size, in the case of a high-order discretization scheme. Considering a Lorentz medium with negligible losses, the propagation characteristics of coarsely resolved waves is examined first, by investigating thoroughly the numerical dispersion relation of a typical discretization scheme. The second part of the study is related to the unbalanced space-time errors in FDTD schemes with dissimilar space-time approximation orders. The authors propose a remedy via the suitable choice of the time-step size, based on the single-frequency minimization of an error expression extracted, again, from the scheme’s numerical dispersion formula. Unlike wave propagation in free space, there exist two parts of the frequency spectrum where waves in a Lorentz medium experience non-physical attenuation and display non-changing propagation constants, due to coarse discretization. The authors also show that an optimum time-step size can be determined, in the case of the (2,4) FDTD scheme, which minimizes the selected error formula at a specific frequency point, promoting more efficient implementations. Unique characteristics displayed by discretized waves, which have been known for non-dispersive media, are examined and verified for the first time in the case of dispersive materials, thus completing the comprehension of the space-time discretization impact on simulated quantities. In addition, the closed-form formula of the optimum time-step enables the efficient implementation of the (2,4) FDTD method, minimizing the detrimental influence of the low-order temporal integration.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-01-21
      DOI: 10.1108/COMPEL-02-2021-0066
      Issue No: Vol. 41 , No. 3 (2022)
       
  • A mixed multiscale FEM for the eddy current problem with ,Φ-Φ
           and vector hysteresis

         This is an Open Access Article Open Access Article

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      Authors: Valentin Hanser , Markus Schöbinger , Karl Hollaus
      Abstract: This work introduces an efficient and accurate technique to solve the eddy current problem in laminated iron cores considering vector hysteresis. The mixed multiscale finite element method based on the based on the T,Φ-Φ formulation, with the current vector potential T and the magnetic scalar potential Φ allows the laminated core to be modelled as a single homogeneous block. This means that the individual sheets do not have to be resolved, which saves a lot of computing time and reduces the demands on the computer system enormously. As a representative numerical example, a single-phase transformer with 4, 20 and 184 sheets is simulated with great success. The eddy current losses of the simulation using the standard finite element method and the simulation using the mixed multiscale finite element method agree very well and the required simulation time is tremendously reduced. The vector Preisach model is used to account for vector hysteresis and is integrated into the mixed multiscale finite element method for the first time.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-01-18
      DOI: 10.1108/COMPEL-02-2021-0053
      Issue No: Vol. 41 , No. 3 (2022)
       
  • Reduced order field-circuit modeling of squirrel cage induction machines
           for automotive applications

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      Authors: Dániel Bíró , Franz Diwoky , Erich Schmidt
      Abstract: The aim of the paper is to investigate the impacts of simplifications of a reduced-order simulation model of squirrel cage induction machines (SCIMs) by numerical experiments. Design of setups to isolate the main influences on the results of the reduced-order model of SCIMs. Results of time-stepping finite element calculations are used as benchmark. Whereas neglecting eddy current effects and the assumption of a sinusoidal rotor current distribution leads to acceptable deviations in regular inverter operation, the sampling and interpolation of the machine parameters in a two-axis coordinate system considerably deteriorate the model accuracy. Using a polar coordinate system for this purpose is expected to significantly improve the model quality. Preparing the ground for a successful, both fast and accurate simulation model of SCIMs as parts of electrified drivetrains.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-01-17
      DOI: 10.1108/COMPEL-03-2021-0092
      Issue No: Vol. 41 , No. 3 (2022)
       
  • Fast and numerically stable Mie solution of EM near field and absorption
           for stratified spheres

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      Authors: Olivér Csernyava , Bálint Péter Horváth , Zsolt Badics , Sándor Bilicz
      Abstract: The purpose of this paper is the development of an analytic computational model for electromagnetic (EM) wave scattering from spherical objects. The main application field is the modeling of electrically large objects, where the standard numerical techniques require huge computational resources. An example is full-wave modeling of the human head in the millimeter-wave regime. Hence, an approximate model or analytical approach is used. The Mie–Debye theorem is used for calculating the EM scattering from a layered dielectric sphere. The evaluation of the analytical expressions involved in the infinite sum has several numerical instabilities, which makes the precise calculation a challenge. The model is validated through an application example with comparing results to numerical calculations (finite element method). The human head model is used with the approximation of a two-layer sphere, where the brain tissues and the cranial bones are represented by homogeneous materials. A significant improvement is introduced for the stable calculation of the Mie coefficients of a core–shell stratified sphere illuminated by a linearly polarized EM plane wave. Using this technique, a semi-analytical expression is derived for the power loss in the sphere resulting in quick and accurate calculations. Two methods are introduced in this work with the main objective of estimating the final precision of the results. This is an important aspect for potentially unstable calculations, and the existing implementations have not included this feature so far.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2022-01-05
      DOI: 10.1108/COMPEL-03-2021-0081
      Issue No: Vol. 41 , No. 3 (2022)
       
  • Unified and non-ideal switch model for analysis of switching circuits

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      Authors: Alperen Pekdemir , Ali Bekir Yildiz
      Abstract: This paper aims to propose a new unified and non-ideal switch model for analysis of switching circuits. The model has a single unified structure that includes all possible states (on, off) of the switches. The analysis with the proposed switch model requires only one topology and uses the single system equation regardless of states of switches. Moreover, to improve accuracy, the model contains the on-state resistance and capacitive effect of switches. The system equations and the states of switches are updated by control variables, used in the model. There are no restrictions on circuit topology and switch connections. Switches can be internally and externally controlled. The non-ideal nature of the model allows the switch to be modeled more realistically and eliminates the drawbacks of the ideal switch concept. After modeling with the proposed switch model, a linear circuit is obtained. Two examples related to switching circuits are included into the study. The results confirm the accuracy of the model. This paper contributes a different switch model for analysis of switching converters to the literature. The main advantage of the model is that it has a unified and non-ideal property. With the proposed switch model, the transient events, like voltage spikes and high-frequency noises, caused by inductor and capacitor elements at switching instants can be observed properly.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2021-12-31
      DOI: 10.1108/COMPEL-04-2021-0126
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2021)
       
  • Design and prototyping of GSM-bluetooth based solar energy remote
           monitoring system

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      Authors: Alper Kerem , Abdusselam Yazgan
      Abstract: The purpose of this study is to monitor the surface cooling of the photovoltaic (PV) panel and the effect of the dust accumulated on the panel surface on the electrical efficiency remotely and instantaneously. An autonomous system has been designed that can measure and record the PV surface temperature, the amount of dust on the surface, current, voltage and power values at certain intervals. It can also perform surface cooling and cleaning with water cycle when the temperature and dust amount reach certain threshold values and transmit these values to the user via global system for mobile communications module, Bluetooth module and graphically with a touchscreen liquid crystal display panel. Thus, it is aimed to benefit from PV at the maximum level, and it was installed in Kahramanmaras Sütçü Imam University Faculty of Engineering and Architecture. An increase in power was observed for PV surface cooling and surface dust removal by 3.78% and 45.99%, respectively. This system is of vital importance in terms of time and energy-saving, especially for solar plants far from the city center, which are difficult to access because of climatic conditions. In other hand for future studies, it is foreseen that more efficiency gains can be achieved by using artificial intelligence and image processing techniques.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2021-12-02
      DOI: 10.1108/COMPEL-10-2021-0384
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2021)
       
  • Torsional vibrations in a shaft train of an air compressor: modification,
           calculation and measurement

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      Authors: Matthias Humer , Stefan Habel
      Abstract: Due to the installation of the new, more powerful gearbox and the dismantling of the exciter machine, the vibration characteristics of the shaft train will be changed. Therefore, it is necessary to reassess the shaft train. It is to be investigated if the shaft train of the compressor meets the general requirements for bending and torsional vibrations and can be safely operated within the electrical network. The purpose of this paper is to show the necessary alignment of modification, calculation and measurement in such a project.. After some modification work on the shaft train of an air compressor, it was necessary to do some engineering calculations regarding the bending natural and torsional natural frequencies and their mode shapes. The correctness of the calculated values was proven by vibration measurements performed at the shaft train in operation. It can be concluded that the change and replacement of rotating equipment in a shaft train never should be done without any engineering calculations in advance and measurements after the component modification. Most important is that the calculation results have to be compared with the measurement results for verifying the calculation assumptions. In the case described above, one can see that theory and practice match well. In addition to this, the very low damping of torsional vibrations is proved again, which can be a significant problem in some situations. Also, today one can find torsional vibration measurements of rotating machines, including frequency, magnitude and damping factor, very seldom. Especially for smaller machines, there are no real comparisons between calculation and measurement are usual. This paper shows that an alignment between theoretical and practical approaches is necessary to avoid operational problems for rotating machines.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2021-11-26
      DOI: 10.1108/COMPEL-07-2021-0252
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2021)
       
  • Performance analysis of selected metaheuristic optimization algorithms
           applied in the solution of an unconstrained task

         This is an Open Access Article Open Access Article

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      Authors: Łukasz Knypiński
      Abstract: The purpose of this paper is to execute the efficiency analysis of the selected metaheuristic algorithms (MAs) based on the investigation of analytical functions and investigation optimization processes for permanent magnet motor. A comparative performance analysis was conducted for selected MAs. Optimization calculations were performed for as follows: genetic algorithm (GA), particle swarm optimization algorithm (PSO), bat algorithm, cuckoo search algorithm (CS) and only best individual algorithm (OBI). All of the optimization algorithms were developed as computer scripts. Next, all optimization procedures were applied to search the optimal of the line-start permanent magnet synchronous by the use of the multi-objective objective function. The research results show, that the best statistical efficiency (mean objective function and standard deviation [SD]) is obtained for PSO and CS algorithms. While the best results for several runs are obtained for PSO and GA. The type of the optimization algorithm should be selected taking into account the duration of the single optimization process. In the case of time-consuming processes, algorithms with low SD should be used. The new proposed simple nondeterministic algorithm can be also applied for simple optimization calculations. On the basis of the presented simulation results, it is possible to determine the quality of the compared MAs.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2021-11-19
      DOI: 10.1108/COMPEL-07-2021-0254
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2021)
       
  • The influence of stacking technologies on structural dynamic properties of
           electric motors iron cores

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      Authors: Sebastian Mönninghoff , Markus Jaeger , Kay Hameyer
      Abstract: It is essential to understand the structural dynamic behavior of electrical machines to predict their acoustic and vibrational behavior. Stacking technology, which is used to manufacture soft magnetic cores, has a strong influence on the material properties. The purpose of this paper is therefore to research the influence of the stacking technologies welding and bonding with bake varnish on the modal properties of iron cores. A finite element simulation model is developed based on homogenization of the stator core. Eigenfrequencies, modeshapes and modal damping ratios are extracted from measurements and are used to validate the simulation model. Modal characteristics depend on the participation of certain material layers at a certain mode. Higher amount of shear deformation results in higher modal damping. Bonded stacks exhibit lower shear stiffness and higher damping ratios. This research paper provides insights to the modal characteristics of iron cores used in electric machine and compares the influence of stacking technologies.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2021-10-11
      DOI: 10.1108/COMPEL-07-2021-0247
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2021)
       
  • Application of model order reduction with Cauer ladder networks to
           industrial inductors

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      Authors: Niels Koester , Oliver Koenig , Alexander Thaler , Oszkár Bíró
      Abstract: The Cauer ladder network (CLN) model order reduction (MOR) method is applied to an industrial inductor. This paper aims to to anaylse the influence of different meshes on the CLN method and their parameters. The industrial inductor is simulated with the CLN method for different meshes. Meshes considering skin effect are compared with equidistant meshes. The inductor is also simulated with the eddy current finite element method (ECFEM) for frequencies 1 kHz to 1 MHz. The solution of the CLN method is compared with the ECFEM solutions for the current density in the conductor and the total impedance. The increase of resistance resulting from the skin effect can be modelled with the CLN method, using a uniform mesh with elements much larger than the skin depth. Meshes taking account of the skin depth are only needed if the electromagnetic fields have to be reconstructed. Additionally, the convergence of the impedance is used to define a stopping criterion without the need for a benchmark solution. The work shows that the CLN method can generate a network, which is capable of mimicking the increase of resistance usually accompanied by the skin effect without using a mesh that takes the skin depth into account. In addition, the proposed stopping criterion makes it possible to use the CLN method as an a priori MOR technique.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2021-12-28
      DOI: 10.1108/COMPEL-02-2021-0058
      Issue No: Vol. 41 , No. 3 (2021)
       
  • Bayesian inference of multi-sensors impedance cardiography for detection
           of aortic dissection

         This is an Open Access Article Open Access Article

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      Authors: Vahid Badeli , Sascha Ranftl , Gian Marco Melito , Alice Reinbacher-Köstinger , Wolfgang Von Der Linden , Katrin Ellermann , Oszkar Biro
      Abstract: This paper aims to introduce a non-invasive and convenient method to detect a life-threatening disease called aortic dissection. A Bayesian inference based on enhanced multi-sensors impedance cardiography (ICG) method has been applied to classify signals from healthy and sick patients. A 3D numerical model consisting of simplified organ geometries is used to simulate the electrical impedance changes in the ICG-relevant domain of the human torso. The Bayesian probability theory is used for detecting an aortic dissection, which provides information about the probabilities for both cases, a dissected and a healthy aorta. Thus, the reliability and the uncertainty of the disease identification are found by this method and may indicate further diagnostic clarification. The Bayesian classification shows that the enhanced multi-sensors ICG is more reliable in detecting aortic dissection than conventional ICG. Bayesian probability theory allows a rigorous quantification of all uncertainties to draw reliable conclusions for the medical treatment of aortic dissection. This paper presents a non-invasive and reliable method based on a numerical simulation that could be beneficial for the medical management of aortic dissection patients. With this method, clinicians would be able to monitor the patient’s status and make better decisions in the treatment procedure of each patient.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2021-12-21
      DOI: 10.1108/COMPEL-03-2021-0072
      Issue No: Vol. 41 , No. 3 (2021)
       
  • Sensitivity analysis for automotive EMC measurements using quasistatic
           Darwin model

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      Authors: Arnold Bingler , Sándor Bilicz , Márk Csörnyei
      Abstract: The purpose of this paper is performing a global sensitivity analysis for automotive electromagnetic compatibility (EMC) measurements related to the CISPR 25 setup in order to examine the effect of the setup uncertainties on the resonance phenomenon. An integral equation formulation is combined with Darwin model and special Green’s functions to model the configuration. The method of Sobol’ indices is used to gain sensitivity factors enhanced with a polynomial chaos metamodel. The proposed model resulted in by orders of magnitude lower number of degrees of freedom and runtime compared to popular numerical methods, e.g. finite element method. The result of the sensitivity study is in good agreement with the underlying physical phenomena and improves the understanding of the resonances. The fast model supplemented by the sensitivity factors can be used in EMC design and optimization. The proposed method is original in the sense of combining a polynomial chaos metamodel with a low-cost integral equation model to reduce the computational demand for the sensitivity study.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2021-12-16
      DOI: 10.1108/COMPEL-02-2021-0054
      Issue No: Vol. 41 , No. 3 (2021)
       
  • Maximum entropy snapshot sampling for reduced basis modelling

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      Authors: Marcus W.F.M. Bannenberg , Fotios Kasolis , Michael Günther , Markus Clemens
      Abstract: The maximum entropy snapshot sampling (MESS) method aims to reduce the computational cost required for obtaining the reduced basis for the purpose of model reduction. Hence, it can significantly reduce the original system dimension whilst maintaining an adequate level of accuracy. The purpose of this paper is to show how these beneficial results are obtained. The so-called MESS method is used for reducing two nonlinear circuit models. The MESS directly reduces the number of snapshots by recursively identifying and selecting the snapshots that strictly increase an estimate of the correlation entropy of the considered systems. Reduced bases are then obtained with the orthogonal-triangular decomposition. Two case studies have been used for validating the reduction performance of the MESS. These numerical experiments verify the performance of the advocated approach, in terms of computational costs and accuracy, relative to gappy proper orthogonal decomposition. The novel MESS has been successfully used for reducing two nonlinear circuits: in particular, a diode chain model and a thermal-electric coupled system. In both cases, the MESS removed unnecessary data, and hence, it reduced the snapshot matrix, before calling the QR basis generation routine. As a result, the QR-decomposition has been called on a reduced snapshot matrix, and the offline stage has been significantly scaled down, in terms of central processing unit time.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2021-12-15
      DOI: 10.1108/COMPEL-02-2021-0050
      Issue No: Vol. 41 , No. 3 (2021)
       
  • Magnetic field simulations using explicit time integration with higher
           order schemes

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      Authors: Bernhard Kähne , Markus Clemens , Sebastian Schöps
      Abstract: A transient magneto-quasistatic vector potential formulation involving nonlinear material is spatially discretized using the finite element method of first and second polynomial order. By applying a generalized Schur complement the resulting system of differential algebraic equations is reformulated into a system of ordinary differential equations (ODE). The ODE system is integrated in time by using explicit time integration schemes. The purpose of this paper is to investigate explicit time integration for eddy current problems with respect to the performance of the first-order explicit Euler scheme and the Runge-Kutta-Chebyshev (RKC) method of higher order. The ODE system is integrated in time using the explicit Euler scheme, which is conditionally stable by a maximum time step size. To overcome this limit, an explicit multistage RKC time integration method of higher order is used to enlarge the maximum stable time step size. Both time integration methods are compared regarding the overall computational effort. The numerical simulations show that a finer spatial discretization forces smaller time step sizes. In comparison to the explicit Euler time integration scheme, the multistage RKC method provides larger stable time step sizes to diminish the overall computation time. The explicit time integration of the Schur complement vector potential formulation of eddy current problems is accelerated by a multistage RKC method.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2021-11-24
      DOI: 10.1108/COMPEL-03-2021-0090
      Issue No: Vol. 41 , No. 3 (2021)
       
  • Deep learning-based surrogate model for fast multi-material topology
           optimization of IPM motor

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      Authors: Hayaho Sato , Hajime Igarashi
      Abstract: This paper aims to present a deep learning–based surrogate model for fast multi-material topology optimization of an interior permanent magnet (IPM) motor. The multi-material topology optimization based on genetic algorithm needs large computational burden because of execution of finite element (FE) analysis for many times. To overcome this difficulty, a convolutional neural network (CNN) is adopted to predict the motor performance from the cross-sectional motor image and reduce the number of FE analysis. To predict the average torque of an IPM motor, CNN is used as a surrogate model. From the input cross-sectional motor image, CNN infers dq-inductance and magnet flux to compute the average torque. It is shown that the average torque for any current phase angle can be predicted by this approach, which allows the maximization of the average torque by changing the current phase angle. The individuals in the multi-material topology optimization are evaluated by the trained CNN, and the limited individuals with higher potentials are evaluated by finite element method. It is shown that the proposed method doubles the computing speed of the multi-material topology optimization without loss of search ability. In addition, the optimized motor obtained by the proposed method followed by simplification for manufacturing is shown to have higher average torque than a reference model. This paper proposes a novel method based on deep learning for fast multi-material topology optimization considering the current phase angle.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2021-11-03
      DOI: 10.1108/COMPEL-03-2021-0086
      Issue No: Vol. 41 , No. 3 (2021)
       
  • Sensorless metal object detection for wireless power transfer using
           machine learning

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      Authors: Yunyi Gong , Yoshitsugu Otomo , Hajime Igarashi
      Abstract: This study aims to realize a sensorless metal object detection (MOD) using machine learning, to prevent the wireless power transfer (WPT) system from the risks of electric discharge and fire accidents caused by foreign metal objects. The data constructed by analyzing the input impedance using the finite element method are used in machine learning. From the loci of the input impedance of systems, the trained neural network (NN), support vector machine and naive Bayes classifier judge if a metal object exists. Then the proposed method is tested by experiments too. In the test using simulated data, all of the three machine learning methods show high accuracy of over 80% for detecting an aluminum cylinder. And in the experimental verifications, the existence of an aluminum cylinder and empty can are successfully identified by a NN. This work provides a new sensorless MOD method for WPT using three machine learning methods. And it shows that NNs obtain high accuracy than the others in both simulated and experimental verifications.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2021-11-01
      DOI: 10.1108/COMPEL-03-2021-0069
      Issue No: Vol. 41 , No. 3 (2021)
       
  • Topology optimization of magnetic cores for WPT using the geometry
           projection method

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      Authors: Yoshitsugu Otomo , Hajime Igarashi
      Abstract: The purpose of this study is to search for an optimal core shape that is robust against misalignment between the transmitting and receiving coils of the wireless power transfer (WPT) device. During the optimization process, the authors maximize the coupling coefficients while minimizing the leakage flux around the coils to ensure the safety of the WPT device. In this study, a novel topology optimization method for WPT devices using the geometry projection method is proposed to optimize the magnetic core shape. This method facilitates the generation of bar-shaped magnetic cores because the material distribution is represented by a set of elementary bars. It is shown that an optimized core shape, which is obtained through topology optimization, effectively increases the net magnetic flux interlinked with the receiving coil and outperforms the conventional core. In the previous topology optimization method, the material distribution is represented by a linear combination of Gaussian functions. However, this method does not usually result in bar-shaped cores, which are widely used in WPT. In this study, the authors propose a novel topology optimization method for WPT devices using geometry projection that is used in structural optimization, such as beam and cantilever shapes.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2021-10-25
      DOI: 10.1108/COMPEL-02-2021-0064
      Issue No: Vol. 41 , No. 3 (2021)
       
  • Towards real-time magnetic dosimetry simulations for inductive charging
           systems

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      Authors: Norman Haussmann , Martin Zang , Robin Mease , Markus Clemens , Benedikt Schmuelling , Matthias Bolten
      Abstract: Inductive charging systems for electrically powered cars produce a magneto-quasistatic field and organism in the vicinity might be exposed to that field. Magneto-quasistatic fields induce electric fields in the human body that should not exceed limits given by the International Commission of Non-Ionizing Radiation protection (ICNIRP) to ensure that no harm is done to the human body. As these electric fields cannot be measured directly, they need to be derived from the measured magnetic flux densities. To get an almost real-time estimation of the harmfulness of the magnetic flux density to the human body, the electric field needs to be calculated within a minimal computing time. The purpose of this study is to identify fast linear equations solver for the discrete Poisson system of the Co-Simulation Scalar Potential Finite Difference scheme on different graphics processing unit systems. The determination of the exposure requires a fast linear equations solver for the discrete Poisson system of the Co-Simulation Scalar Potential Finite Difference (Co-Sim. SPFD) scheme. Here, the use of the AmgX library on NVIDIA GPUs is presented for this task. Using the AmgX library enables solving the equation system resulting from an ICNIRP recommended human voxel model resolution of 2 mm in less than 0.5 s on a single NVIDIA Tesla V100 GPU. This work is one essential advancement to determine the exposure of humans from wireless charging system in near real-time from in situ magnetic flux density measurements.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2021-10-18
      DOI: 10.1108/COMPEL-03-2021-0084
      Issue No: Vol. 41 , No. 3 (2021)
       
  • Model order reduction of nonlinear eddy-current field using parameterized
           CLN

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      Authors: Miwa Tobita , Hamed Eskandari , Tetsuji Matsuo
      Abstract: The authors derive a nonlinear MOR based on the Cauer ladder network (CLN) representation, which serves as an application of the parameterized MOR. Two parametrized CLN representations were developed to handle the nonlinear magnetic field. Simulations using the parameterized CLN were also conducted using an iron-cored inductor model under the first-order approximation. This work studies the effect of parameter variations on reduced systems and aims at developing a general formulation for parametrized model order reduction (MOR) methods with the dynamical transition of parameterized state. Terms including time derivatives of basis vectors appear in nonlinear state equations, in addition to the linear network equations of the CLN method. The terms are newly derived by an exact formulation of the parameterized CLN and are named parameter variation terms in this study. According to the simulation results, the parameter variation terms play a significant role in the nonlinear state equations when reluctivity is used, while they can be neglected when differential reluctivity is used. The computational time of nonlinear transient analyses can be greatly reduced by applying the parameterized CLN when the number of time steps is large. The authors introduced a general representation for the dynamical behavior of the reduced system with time-varying parameters, which has not been theoretically discussed in previous studies. The effect of the parameter variations is numerically given as a form of parameter variation terms by the exact derivation of the nonlinear state equations. The influence of parameter variation terms was confirmed by simulation.
      Citation: COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
      PubDate: 2021-09-03
      DOI: 10.1108/COMPEL-02-2021-0065
      Issue No: Vol. 41 , No. 3 (2021)
       
  • COMPEL - The international journal for computation and mathematics in
           electrical and electronic engineering

    • Free pre-print version: Loading...

       
 
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