Subjects -> ENERGY (Total: 414 journals)
    - ELECTRICAL ENERGY (12 journals)
    - ENERGY (252 journals)
    - ENERGY: GENERAL (7 journals)
    - NUCLEAR ENERGY (40 journals)
    - PETROLEUM AND GAS (58 journals)
    - RENEWABLE ENERGY (45 journals)

ENERGY (252 journals)                  1 2 | Last

Showing 1 - 200 of 406 Journals sorted alphabetically
ACS Applied Energy Materials     Hybrid Journal   (Followers: 4)
ACS Energy Letters     Hybrid Journal   (Followers: 4)
Advanced Energy and Sustainability Research     Open Access   (Followers: 5)
Advanced Materials Technologies     Hybrid Journal   (Followers: 2)
Advances in Applied Energy     Open Access   (Followers: 2)
Advances in Building Energy Research     Hybrid Journal   (Followers: 11)
Advances in Energy and Power     Open Access   (Followers: 16)
Advances in High Energy Physics     Open Access   (Followers: 23)
Advances in Natural Sciences : Nanoscience and Nanotechnology     Open Access   (Followers: 28)
American Journal of Energy and Environment     Open Access   (Followers: 4)
American Journal of Energy Research     Open Access   (Followers: 7)
Annals of Nuclear Energy     Hybrid Journal   (Followers: 7)
Annual Reports on NMR Spectroscopy     Full-text available via subscription   (Followers: 4)
Annual Review of Resource Economics     Full-text available via subscription   (Followers: 11)
Applications in Energy and Combustion Science     Open Access   (Followers: 3)
Applied Energy     Partially Free   (Followers: 26)
Applied Nanoscience     Open Access   (Followers: 7)
Applied Solar Energy     Hybrid Journal   (Followers: 20)
Archives of Thermodynamics     Open Access   (Followers: 10)
Asian Bulletin of Energy Economics and Technology     Open Access   (Followers: 1)
Atomic Energy     Hybrid Journal   (Followers: 5)
Batteries     Open Access   (Followers: 8)
Batteries & Supercaps     Hybrid Journal   (Followers: 5)
Biofuel Research Journal     Open Access   (Followers: 1)
Biofuels     Hybrid Journal   (Followers: 11)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 10)
BioPhysical Economics and Resource Quality     Hybrid Journal  
BMC Energy     Open Access  
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 50)
Canadian Water Resources Journal     Hybrid Journal   (Followers: 18)
Carbon Energy     Open Access   (Followers: 1)
Carbon Management     Hybrid Journal   (Followers: 5)
Carbon Resources Conversion     Open Access   (Followers: 2)
CERN courier. International journal of high energy physics     Free   (Followers: 8)
Chain Reaction     Full-text available via subscription  
Clean Energy     Open Access   (Followers: 2)
Clean Technologies     Open Access   (Followers: 1)
Clefs CEA     Full-text available via subscription   (Followers: 1)
Climate and Energy     Full-text available via subscription   (Followers: 6)
Computational Water, Energy, and Environmental Engineering     Open Access   (Followers: 5)
CPSS Transactions on Power Electronics and Applications     Open Access   (Followers: 2)
CSEE Journal of Power and Energy Systems     Open Access   (Followers: 1)
CT&F - Ciencia, Tecnología y Futuro     Open Access  
Current Opinion in Green and Sustainable Chemistry     Hybrid Journal  
Dams and Reservoirs     Hybrid Journal   (Followers: 3)
Development of Energy Science     Open Access   (Followers: 4)
Discover Energy     Open Access  
Discover Sustainability     Open Access   (Followers: 3)
Distributed Generation & Alternative Energy Journal     Hybrid Journal   (Followers: 3)
e-Prime : Advances in Electrical Engineering, Electronics and Energy     Open Access   (Followers: 2)
E3S Web of Conferences     Open Access  
Economics and Policy of Energy and the Environment     Full-text available via subscription   (Followers: 13)
Electricity Journal     Hybrid Journal   (Followers: 1)
Energetic Materials Frontiers     Open Access  
ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations     Open Access  
Energy     Partially Free   (Followers: 40)
Energy & Environment     Hybrid Journal   (Followers: 25)
Energy & Fuels     Hybrid Journal   (Followers: 27)
Energy and AI     Open Access   (Followers: 1)
Energy and Buildings     Hybrid Journal   (Followers: 12)
Energy and Climate Change     Hybrid Journal   (Followers: 4)
Energy and Emission Control Technologies     Open Access   (Followers: 3)
Energy and Environment Focus     Free   (Followers: 7)
Energy and Environment Research     Open Access   (Followers: 13)
Energy and Environmental Engineering     Open Access   (Followers: 5)
Energy and Power     Open Access   (Followers: 18)
Energy and Power Engineering     Open Access   (Followers: 23)
Energy Conversion and Economics     Open Access  
Energy Conversion and Management     Hybrid Journal   (Followers: 15)
Energy Conversion and Management : X     Open Access   (Followers: 1)
Energy Efficiency     Hybrid Journal   (Followers: 9)
Energy Geoscience     Open Access  
Energy Informatics     Open Access  
Energy Journal The     Hybrid Journal   (Followers: 14)
Energy Materials : Materials Science and Engineering for Energy Systems     Hybrid Journal   (Followers: 19)
Energy Nexus     Open Access  
Energy Policy     Partially Free   (Followers: 73)
Energy Prices and Taxes     Full-text available via subscription   (Followers: 6)
Energy Reports     Open Access   (Followers: 5)
Energy Research & Social Science     Full-text available via subscription   (Followers: 11)
Energy Science & Engineering     Open Access   (Followers: 6)
Energy Science and Technology     Open Access   (Followers: 10)
Energy Storage     Hybrid Journal   (Followers: 2)
Energy Storage Materials     Full-text available via subscription   (Followers: 5)
Energy Strategy Reviews     Open Access   (Followers: 8)
Energy Studies Review     Open Access   (Followers: 5)
Energy Systems     Hybrid Journal   (Followers: 11)
Energy Technology     Partially Free   (Followers: 5)
Energy Technology & Policy     Open Access   (Followers: 2)
Energy Transitions     Open Access  
Energy, Ecology and Environment     Hybrid Journal  
Energy, Sustainability and Society     Open Access   (Followers: 15)
EnergyChem     Hybrid Journal   (Followers: 1)
Environmental Progress & Sustainable Energy     Hybrid Journal   (Followers: 7)
EPJ Photovoltaics     Open Access   (Followers: 2)
eScience     Open Access   (Followers: 1)
Facta Universitatis, Series : Electronics and Energetics     Open Access  
Forces in Mechanics     Open Access   (Followers: 2)
Foundations and Trends® in Renewable Energy     Full-text available via subscription   (Followers: 4)
Frontiers in Energy     Hybrid Journal   (Followers: 4)
Frontiers in Energy Research     Open Access   (Followers: 5)
Fuel and Energy Abstracts     Full-text available via subscription   (Followers: 7)
Fuel Communications     Open Access   (Followers: 2)
Functional Materials Letters     Hybrid Journal   (Followers: 3)
Gcb Bioenergy     Open Access   (Followers: 2)
Geomechanics and Geophysics for Geo-Energy and Geo-Resources     Hybrid Journal  
Geomechanics for Energy and the Environment     Full-text available via subscription  
Geothermal Energy     Open Access   (Followers: 5)
Global Challenges     Open Access  
Global Energy Interconnection     Open Access  
Global Energy Law and Sustainability     Hybrid Journal  
Global Transitions     Open Access   (Followers: 1)
Global Transitions Proceedings     Open Access  
Green Energy & Environment     Open Access   (Followers: 2)
High Voltage     Open Access  
IEEE Open Access Journal of Power and Energy     Open Access   (Followers: 1)
IEEE Open Journal of Power Electronics     Open Access   (Followers: 12)
IEEE Power and Energy     Full-text available via subscription   (Followers: 36)
IEEE Transactions on Energy Conversion     Hybrid Journal   (Followers: 16)
IEEE Transactions on Nuclear Science     Hybrid Journal   (Followers: 10)
IEEE Transactions on Power Systems     Hybrid Journal   (Followers: 45)
IET Energy Systems Integration     Open Access   (Followers: 1)
IET Power Electronics     Open Access   (Followers: 76)
IET Smart Grid     Open Access   (Followers: 2)
Ingeniería Energética     Open Access  
Innovations : Technology, Governance, Globalization     Hybrid Journal   (Followers: 10)
International Journal of Alternative Propulsion     Hybrid Journal   (Followers: 23)
International Journal of Ambient Energy     Hybrid Journal  
International Journal of Applied Power Engineering     Open Access   (Followers: 4)
International Journal of Clean Coal and Energy     Open Access   (Followers: 2)
International Journal of Coal Science & Technology     Open Access   (Followers: 1)
International Journal of Electric and Hybrid Vehicles     Hybrid Journal   (Followers: 8)
International Journal of Energy & Engineering Sciences     Open Access  
International Journal of Energy and Environmental Engineering     Open Access   (Followers: 3)
International Journal of Energy and Power     Open Access   (Followers: 8)
International Journal of Energy and Smart Grid     Open Access   (Followers: 1)
International Journal of Energy and Statistics     Hybrid Journal   (Followers: 3)
International Journal of Energy and Water Resources     Hybrid Journal  
International Journal of Energy Research     Hybrid Journal   (Followers: 8)
International Journal of Global Energy Issues     Hybrid Journal   (Followers: 8)
International Journal of Green Energy     Hybrid Journal   (Followers: 8)
International Journal of Hydrogen Energy     Partially Free   (Followers: 19)
International Journal of Nuclear Desalination     Hybrid Journal   (Followers: 1)
International Journal of Nuclear Energy Science and Technology     Hybrid Journal   (Followers: 4)
International Journal of Nuclear Governance, Economy and Ecology     Hybrid Journal  
International Journal of Nuclear Hydrogen Production and Applications     Hybrid Journal   (Followers: 1)
International Journal of Nuclear Knowledge Management     Hybrid Journal   (Followers: 2)
International Journal of Power and Energy Conversion     Hybrid Journal   (Followers: 1)
International Journal of Smart Grid and Green Communications     Hybrid Journal   (Followers: 2)
International Journal of Sustainable Energy     Hybrid Journal   (Followers: 12)
International Journal of Sustainable Energy Planning and Management     Open Access   (Followers: 5)
International Journal of Sustainable Engineering     Hybrid Journal   (Followers: 4)
International Journal of Thermodynamics     Open Access   (Followers: 15)
International Journal of Turbomachinery, Propulsion and Power     Open Access   (Followers: 23)
Joule     Hybrid Journal   (Followers: 5)
Journal of Alternate Energy Sources & Technologies     Full-text available via subscription   (Followers: 2)
Journal of Building Performance Simulation     Hybrid Journal   (Followers: 5)
Journal of China Coal Society     Open Access  
Journal of Computational Multiphase Flows     Open Access   (Followers: 1)
Journal of Energy     Open Access   (Followers: 2)
Journal of Energy & Natural Resources Law     Hybrid Journal   (Followers: 5)
Journal of Energy and Environment Technology of Graduate School Siam Technology College     Open Access  
Journal of Energy Chemistry     Full-text available via subscription   (Followers: 3)
Journal of Energy in Southern Africa     Open Access   (Followers: 2)
Journal of Energy Research and Reviews     Open Access  
Journal of Energy Storage     Full-text available via subscription   (Followers: 4)
Journal of Energy Systems     Open Access  
Journal of Energy Technologies and Policy     Open Access   (Followers: 5)
Journal of Energy, Environment & Carbon Credits     Full-text available via subscription   (Followers: 4)
Journal of Energy, Mechanical, Material and Manufacturing Engineering     Open Access   (Followers: 3)
Journal of Fusion Energy     Hybrid Journal   (Followers: 2)
Journal of International Energy Policy     Open Access   (Followers: 4)
Journal of Modern Power Systems and Clean Energy     Open Access   (Followers: 9)
Journal of Nano Energy and Power Research     Full-text available via subscription   (Followers: 4)
Journal of Nuclear Energy Science & Power Generation Technology     Hybrid Journal   (Followers: 2)
Journal of Ocean and Climate     Open Access   (Followers: 9)
Journal of Ocean Engineering and Marine Energy     Hybrid Journal   (Followers: 2)
Journal of Photochemistry and Photobiology A: Chemistry     Hybrid Journal   (Followers: 3)
Journal of Photochemistry and Photobiology B: Biology     Hybrid Journal   (Followers: 4)
Journal of Photochemistry and Photobiology C: Photochemistry Reviews     Full-text available via subscription   (Followers: 3)
Journal of Photonics for Energy     Hybrid Journal   (Followers: 2)
Journal of Physical Chemistry C     Hybrid Journal   (Followers: 36)
Journal of Power and Energy Engineering     Open Access   (Followers: 2)
Journal of Power Electronics     Hybrid Journal   (Followers: 8)
Journal of Power Electronics & Power Systems     Full-text available via subscription   (Followers: 19)
Journal of Power Sources Advances     Open Access  
Journal of Renewable Energy     Open Access   (Followers: 8)
Journal of Solar Energy     Open Access   (Followers: 11)
Journal of Solar Energy Engineering     Full-text available via subscription   (Followers: 18)
Journal of Sustainable Bioenergy Systems     Full-text available via subscription  
Journal of Technology Innovations in Renewable Energy     Hybrid Journal   (Followers: 2)
Journal of Technology Management for Growing Economies     Open Access   (Followers: 4)
KnE Energy     Open Access  
Materials for Renewable and Sustainable Energy     Open Access   (Followers: 6)
Materials Reports : Energy     Open Access   (Followers: 1)
Materials Today Energy     Hybrid Journal   (Followers: 2)
Mekanika : Jurnal Teknik Mesin i     Open Access  
Michigan Journal of Sustainability     Open Access   (Followers: 1)
Multequina     Open Access  
Natural Resources     Open Access  

        1 2 | Last

Similar Journals
Journal Cover
IEEE Transactions on Energy Conversion
Journal Prestige (SJR): 1.377
Citation Impact (citeScore): 5
Number of Followers: 16  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0885-8969
Published by IEEE Homepage  [228 journals]
  • IEEE Power & Energy Society

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      Abstract: Presents a listing of the editorial board, board of governors, current staff, committee members, and/or society editors for this issue of the publication.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Information for Authors

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      Abstract: These instructions give guidelines for preparing papers for this publication. Presents information for authors publishing in this journal.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
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      Abstract: This page or pages intentionally left blank.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Analysis of Magnetostrictive Effect on Low-Frequency Force Wave in
           Rotating Magnetic Field

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      Authors: Xin Zhang;Jiajun He;Lihua Zhu;Pu Li;
      Pages: 3 - 9
      Abstract: The electromagnetic vibration and noise in motors is mainly induced by electromagnetic forces and magnetostrictive force. The low-frequency force waves have a great influence on the deformation of the motor stator core due to resonance. In this article, a 2-D electromagnetic-mechanical coupling transient model was built based on the quadratic magnetic domain rotation model, considering the magnetostrictive characteristics of silicon steel sheet and the magnetoelastic coupling of materials. Through numerical simulation calculation and analysis, it was found that low-frequency force waves appeared in the motor stator, and the large amplitudes happened on the single and twice power frequency. The actual experimental measurements were designed in the rotating motor and the transformer to verify this phenomenon. It is concluded that the rotating field or the magnetic path distortion leads to the large amplitude at single-power frequency or rotating field frequency on the electrical equipment.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Model Predictive Control for Multi-Port Modular Multilevel Converters in
           Electric Vehicles Enabling HESDs

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      Authors: Mohamed O. Badawy;Mohit Sharma;Carlos Hernandez;Ali Elrayyah;Samuel Guerra;Joshua Coe;
      Pages: 10 - 23
      Abstract: In this paper, the authors propose a model predictive control (MPC) algorithm for multi-port modular multilevel converters (MP-MMCs). MP-MMCs are used to enable the use of hybrid energy storage devices (HESDs) in a scalable energy management system (EMS) for electric vehicle (EV) applications. HESDs refer to the use of multiple types of energy storage cells in an EV drivetrain system. In this paper, battery cells are sized for the EV energy density, while ultra-capacitor cells are used for high acceleration periods. This system reduces the EV drivetrain's weight and size due to eliminating high-power inverters and their filtering components. Using MPC, this system can achieve the following control objectives: 1) extend the battery cells lifetime and driving range by shielding them from high power pulses, 2) balance the state of charge levels of every storage cell, 3) increase the system efficiency through optimizing the supplied motor voltage and reducing the switching losses. Moreover, the proposed solution provides means for onboard high-power charging of EV storage cells. Finally, validation results are provided in the paper using a developed hardware prototype, co-simulations, and hardware in the loop system to verify the system's effectiveness.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • A Novel Structure of Tubular Staggered Transverse-Flux Permanent-Magnet
           Linear Generator for Wave Energy Conversion

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      Authors: Shuheng Qiu;Wei Zhao;Chi Zhang;Jonathan K. H. Shek;Haifeng Wang;
      Pages: 24 - 35
      Abstract: This paper presents a novel linear generator structure of three-phase tubular staggered transverse flux permanent magnet linear generator (TSTF-PMLG) for wave energy conversion. Compared with conventional TF-PMLGs, the new structure has a simpler magnetic flux path, high mechanical strength, low cogging force and more suitable for low-speed direct driven situation. In the primary of TSTF-PMLG, a nonuniform teeth steel sheets structure is used and steel sheets of different phases are in different angel so that the groove can be separated by staggered steel sheets in the plane perpendicular to the direction of movement. By the analytical model, the operation principle of the proposed linear generator is explained. Then through the finite element analysis, the distribution of the main flux and leakage flux, the no-load characteristics and output power of TSTF-PMLG are analyzed in detail. And the influence of the lamination factor on the output characteristics of the TSTF-PMLG is obtained. Subsequently the appropriate design parameters of the TSTF-PMLG are selected. During the TSTF-PMLG processing, the method of mixing silicon steel sheets and fiberglass board is used to limiting the lamination factor. Finially, a prototype of 150 W rated power and 79% rated efficiency is presented. And the experimental results verify the theoretical analysis.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • MAF-DCGI Based Single-Phase Uninterrupted PV-Battery System Under
           Unintentional Islanding

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      Authors: Sai Pranith;Shailendra Kumar;Bhim Singh;T. S. Bhatti;
      Pages: 36 - 49
      Abstract: The unintentional islanding is a critical issue in grid-connected solar battery systems in case of grid loss. This interrupts the power supply to the loads. Therefore, in this paper, an uninterrupted photovoltaic (PV)-battery energy storage (BES) system is presented to improve the reliability of the power supply. Besides, this system also furnishes the mitigation of load harmonics current and nonactive power compensation along with peak energy optimization for the PV array. The PV-battery system comprises a battery control by converter and an inverter regulated by an adaptive algorithm. The bidirectional controller regulates the voltage of the DC link capacitor. The moving average filter (MAF) - dual cascaded generalized integrator (DCGI) based adaptive control algorithm is used for utility-interactive operation and a voltage-based control algorithm is used for a standalone mode of operation. MAF-DCGI based phase-locked loop (PLL) is used for synchronization and islanding detection mechanism. An energy management system is used to manage the power flow between the devices in different modes of operation and smooth connection to the grid satisfying the IEEE 1547-2018 standard.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Structure and Operating Performance of a Double Electrical Excitation
           Synchronous Generator With Embedded Brushless Synchronous Exciter
           Utilizing DC-Field Excitation

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      Authors: Shushu Zhu;Chuang Liu;Kai Wang;Zhou Zhou;Junyue Yu;
      Pages: 50 - 64
      Abstract: A double electrical excitation synchronous generator (DEESG) with an embedded brushless exciter is proposed to achieve brushless excitation for a brush excitation electrical excitation synchronous generator (EESG). A set of extra stator excitation windings is placed in the stator slots with armature coils to generate a static magnetic field. There are two sets of windings on the rotor: pulsating excitation winding (Wp) and main excitation winding (WF). The winding direction of the coils of Wp and WF on the same rotor-pole-body is the same. The AC voltage of Wp which is induced by static magnetic field provides dc excitation current for WF by diodes. Both currents in the coils of the Wp and WF generate the rotor excitation flux which induces voltage in the armature coils. In this study, the operating principle is analyzed theoretically. The no-load and load characteristics are studied using Maxwell. The influence of the novel winding structure on the output voltage when the load varies is also analyzed. The voltage regulation rate of DEESG is reduced because the rotor excitation currents can be increased with armature current. A 1.5 kVA prototype is fabricated for experiment. The measured results agree well with the theoretical and FE-predicted results.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Effect of Rotor Topology on the Performance of Counter-Rotating
           Double-Sided Flux Switching Permanent Magnet Generator

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      Authors: Seyed Armin Mirnikjoo;Farough Asadi;Karim Abbaszadeh;Seyed Ehsan Abdollahi;
      Pages: 65 - 74
      Abstract: Recently, electric power generation from direct-drive counter-rotating wind turbine has gained considerable attention. Consequently, employing an efficient and a high power density electric generator is important. In this regard, flux switching permanent magnet generator with double-sided structure is one of the potential candidates for this purpose due to its features like inherently magnetic gearing effect, high power density, high reliability, and robust rotor structure. In this regard, rotor structure of double-sided flux switching permanent magnet generator is one of the most important factors which can highly affect the machine's performance due to the fact that, rotor geometry is the main part in the flux switching procedure of double-sided flux switching permanent magnet generator. Consequently, this paper presents a comprehensive analysis of counter-rotating double-sided flux switching permanent magnet generator with segmented rotor and laminated rotor in which a bridge is located between adjacent rotor poles. The finite element simulations and experimental tests results showed that the proposed generator with laminated rotor gained from the higher power density in comparison with the segmented one whereas in the case of segmented rotor, the torque ripple is lower.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Sequence Impedance Measurement of Utility-Scale Wind Turbines and
           Inverters – Reference Frame, Frequency Coupling, and MIMO/SISO Forms

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      Authors: Shahil Shah;Przemyslaw Koralewicz;Vahan Gevorgian;Robb Wallen;
      Pages: 75 - 86
      Abstract: Sequence impedance responses are increasingly used for the stability analysis of converter-grid systems; however, many aspects of the sequence impedance measurement process, particularly those resulting from the frequency coupling between the positive- and negative-sequence impedances, are not yet fully explored. Existing methods for measuring sequence impedance with frequency coupling are complicated, not suitable for large wind turbines and inverters, and they can measure the sequence impedance in only one of the MIMO and SISO forms. This paper shows that the sequence impedance has a reference frame similar to the dq impedance and presents a method for measuring the sequence impedance with frequency coupling. The proposed method aligns the sequence impedance reference frame based on the estimation of the grid voltage angle and obtains the impedance response in both MIMO and SISO forms. The paper also demonstrates the impact of the fundamental frequency on the accuracy of the impedance measurements. The proposed method and practical issues associated with the impedance measurement of utility-scale wind turbines and inverters are demonstrated on a 1.9-MW Type III wind turbine and a 2.2-MVA inverter using an impedance measurement system built around a 7-MW/13.8-kV grid simulator and a 5-MW dynamometer.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Effects of Rotor Skewing on the Vibration of Permanent Magnet Synchronous
           Motors With Elastic-Plastic Stator

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      Authors: Shu Wang;Hongfeng Li;
      Pages: 87 - 96
      Abstract: Rotor-step straight skewing is a common method to reduce electromagnetic vibration of permanent magnet synchronous motors (PMSMs). However, the difference of the radial electromagnetic forces received by different axial positions of the stator caused by the elastic-plastic material is generally ignored in the theoretical analysis to determine the skewing structure, which makes the vibration suppression effect of the structure far less than expected in practical applications. Take a 48-slot 8-pole interior PMSM as an example, this paper compares the suppression effects of rotor-step straight skewing and rotor-step zigzag skewing when the elastoplasticity of the stator material is considered. It is pointed out that the rotor-step zigzag skewing can overcome the limitation of the straight skewing in restraining electromagnetic vibration in practical application. Based on the theoretical formula and multi-physical field simulation, the selection rules of the rotor-step zigzag skewing angle and segment number are summarized. Finally, the rationality and effectiveness of the simulation method are verified by experiments on the prototype.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Design and Starting Performance Study of a Soft-Start Brushless Doubly Fed
           Machine

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      Authors: Chaohao Kan;Jie Zheng;Xuefan Wang;Qunjing Wang;
      Pages: 97 - 108
      Abstract: Traditional brushless doubly fed machine(BDFM) are difficult to take into account both high starting characteristics and high operating efficiency, which limits the range of industrial application. In order to solve this problem, with the composite coil structure adopted by the rotor winding of BDFM and based on the magnetomotive force(MMF) harmonic theory of stator winding, this paper presents a soft starting method. This method enables the motor to automatically increase the starting resistance when starting, which reduces the starting current and the impact on the grid. And the mechanical characteristics become hard. When running, the starting resistance returns to normal, which makes the running efficiency high. First, this paper introduces the working principle of soft-start BDFM, and gives several designs of stator winding and rotor winding(RW) for comparative analysis. Then, the two-dimensional transient magnetic field analysis method is used to analyze the magnetic field changes. Finally, a test prototype was developed and an experimental platform was built. Under soft starting and asynchronous starting, the no-load and load starting performance of the soft-start BDFM is studied through simulation and experiment. The results confirmed the feasibility of the design.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Impacts of Phase-Locked Loop and Reactive Power Control on Inertia
           Provision by DFIG Wind Turbine

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      Authors: Li Sun;Xiaowei Zhao;
      Pages: 109 - 119
      Abstract: This paper evaluates the impacts of the phase-locked loop (PLL) and reactive power control (RPC) on the inertia provision of DFIG wind turbine (WT), by taking a wide range of system loading conditions (i.e., from the reactive injection to absorption) into consideration. First, a linearized model is developed for DFIG WT to describe the motion of its internal voltage phase, and the derived motion equation provides a way for analytical estimation on DFIG WT’s inertia provision. After formulating the equivalent inertia, it is then used to conduct a character study on the equivalent inertia subject to different PLL and RPC settings. In this course, the loading condition of DFIG WT changes from the reactive injection to absorption to give a systematic study. Finally, the theoretical outcomes are validated by the simulations on a modified 3-machine, 9-node test system.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Third-Harmonic Current Injection for Wear-Out Reduction in Single-Phase PV
           Inverters

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      Authors: Rafaela de Paula Silva;Diogo Borges da Silveira;Rodrigo C. de Barros;João Marcus S. Callegari;Allan Fagner Cupertino;Heverton Augusto Pereira;
      Pages: 120 - 131
      Abstract: The expansion of grid-connected photovoltaic (PV) systems over the years has been followed by concerns about the PV inverter reliability. It is well known that single-phase grid-connected PV inverter has a double-line frequency ripple in the dc-link voltage, which increases the wear-out failure probability of the dc-link capacitor and affects the overall inverter reliability. This work uses a third-harmonic current injection to attenuate the double-line frequency ripple in the dc-link capacitor voltage and to improve the PV system reliability. An analytical model capable to describe the effects of the third-harmonic current injection method in the dc-link capacitor is derived. The proposed strategy is validated by simulation and experimental results. The lifetime evaluation is developed considering a 3 kVA PV inverter and one-year mission profiles. The PV inverter failure probability considering an operation period equal to 20 years decreased in 27.17% for the adopted case study. Moreover, this strategy provides a straightforward retrofit of the current inverter technology, requiring no hardwarechanges.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Modeling and Analysis of Dual-Winding Bearingless Flux-Switching Permanent
           Magnet Motor Considering Magnetic Saturation Based on Subdomain Model

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      Authors: Zhengshan Cui;Yangzhong Zhou;Jing Zhang;Wangtong Liu;
      Pages: 132 - 144
      Abstract: Dual-winding bearingless flux-switching permanent magnet machine (BFSPMM) is composed of power winding and suspension winding. The permanent magnet and the power winding provide a biased air gap magnetic field, and the suspension winding generates an air gap modulation magnetic field. The structure of stator and rotor are double salient poles. This paper proposes a subdomain model for the on-load field prediction in dual-winding BFSPMM. In the developed model, the field domain is divided into seven types of subdomains, viz. rotor slot, internal air gap, stator slot, permanent magnet slot upper layer, permanent magnet slot lower layer, permanent magnet, and external air gap. The electromagnetic parameters of the motor are analyzed, including air gap flux density, flux linkage, back-EMF, suspension forces, and electromagnetic torque. Based on the principle of conservation of magnetomotive force, a distributed equivalent magnetic circuit model is proposed to compensate for the magnetic saturation. Finally, the analytical predictions are verified by finite-element analysis and prototype experiments.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Experimental Parameter Estimation of Induction Motor Based on Transient
           and Steady-State Responses in Synchronous and Rotor Reference Frames

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      Authors: Zahra Masoumi;Bijan Moaveni;Mojtaba Khorshidi;Jawad Faiz;Sayed Mohammad Mousavi Gazafrudi;
      Pages: 145 - 152
      Abstract: This paper presents a method for estimating the equivalent circuit parameters of three-phase induction motors by employing the extended Kalman filter. In this method, the stator currents and voltages, and rotor speed of the motor under an unspecified load and in unsaturated condition are considered. The rotor resistance, mutual inductance, and stator leakage inductance are estimated using the synchronous reference frame in the steady-state mode. Also, the rotor leakage inductance is estimated using the rotor reference frame in the transient mode. Experimental data are used to validate the analytical technique.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Non-Cascaded Model-Free Predictive Speed Control of SMPMSM Drive System

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      Authors: Jingkui Mao;Hongmei Li;Liguo Yang;Hengguo Zhang;Liwen Liu;Xianling Wang;Jin Tao;
      Pages: 153 - 162
      Abstract: The cascaded structure is generally adopted in the permanent magnet synchronous motor drive system, however, the speed dynamic performance is always deteriorated due to the limited bandwidth of speed loop when the linear controller is employed. Therefore, in order to realize quick dynamic response, the speed loop is eliminated in the non-cascaded control structure, and the non-cascaded model-free predictive speed control is proposed in this paper. First, the ultra-local model of SMPMSM drive system is established with a compound variable which implicitly unifies the speed and current of different time scales, and then the Lyapunov function is designed to derive control law and generate the inverter reference voltage automatically by considering the delay of digital control. Moreover, the inverter reference voltage is further modified under voltage and current constraints to guarantee system safety and reliable operation. Finally, the feasibility and validity of the proposed method has been verified by system simulation and experimental researches.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Open and Short Circuit Post-Fault Control Strategies for Multi-Three-Phase
           Interior Permanent Magnet Machines

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      Authors: Azlia Abdul Rahman;Alessandro Galassini;Michele Degano;Giampaolo Buticchi;G. Cristián Pesce;Chris Gerada;Serhiy Bozhko;Haider A.F. Almurib;
      Pages: 163 - 174
      Abstract: This paper presents a post-fault current control strategy for dual three-phase Interior Permanent Magnet (IPM) synchronous machines. The current controllers are designed based on the Vector Space Decomposition (VSD) algorithm. This take into account the equivalent harmonic inductance variation, which is then used to introduce the post-fault compensation control. A double three-phase IPM machine is modelled and operated in three different operating conditions: nominal, one three-phase set in short-circuit (SC), and one three-phase set in open-circuit (OC). By keeping the current loop bandwidth constant, the proposed fault-tolerant current controllers guarantee the same dynamic performance of the remaining healthy module after the faults occurred. In OC fault, the proportional and integral (PI) controllers are re-designed while adapting the inductance variation. For the SC case, constant stability margins are provided by cascading a novel lag compensator to the nominal controller. The current dynamics responses are analysed in both healthy and faulty conditions by means of Matlab/Simulink simulations. Experimental results on a 30$mathbf {kW}$ six-phase IPM machine prototype with isolated neutral points and supplied by two custom three-phase converters, are demonstrating the effectiveness of the proposed control strategies.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Modeling and Control of DAB Converter Applied to Batteries Charging

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      Authors: Pablo F. S. Costa;Pedro H. B. Löbler;Leandro Roggia;Luciano Schuch;
      Pages: 175 - 184
      Abstract: For the connection of the generation system (renewable energy source utilization system) to the energy storage system (ESS), the use of a DC-DC converter with high voltage gain, bidirectionality in the power flow and galvanic isolation becomes necessary. In this paper, the dual active bridge (DAB) converter with topological modification in the output is used. The mathematical modeling of the converter is performed through two methods: the generalized average model and the output current linearization model. In addition, a comparative analysis between the methods is carried out and the design of current and voltage controllers for the DAB are developed applying the more reliable model. Finally, experimental results are presented.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Digital Current Controller With a Novel Active Damping Design for IPMSM

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      Authors: Shuying Yang;Qishuai Wang;Zhen Xie;Xing Zhang;Liuchen Chang;
      Pages: 185 - 197
      Abstract: Internal model control gets wide attentions in electric drives for its outstanding robustness. Underdamped oscillations however, always can be seen in the synchronous d- and q- axis components of the stator currents if without proper extra damping elements included, especially under the low sampling to fundamental frequency ratios. The reasons for these oscillations are analyzed in the discrete-time domain other than as usually done in the continuous-time domain. Following that, a distinctive active damping matrix is proposed for the current closed-loop control of interior permanent magnet synchronous motors (IPMSMs). As a result, the anti-disturbance capability is enhanced, allowing the oscillations, often seen in the d- and q-axis current components, suppressed very well. Compared with other damping methods, the typical PI structure is still retained, which is desired on the point of engineering view. At last, the analysis as well as the damping effectiveness is validated through experiments.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Model Predictive Control With a Cascaded Hammerstein Neural Network of a
           Wind Turbine Providing Frequency Containment Reserve

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      Authors: Nezmin Kayedpour;Arash E. Samani;Jeroen D. M. De Kooning;Lieven Vandevelde;Guillaume Crevecoeur;
      Pages: 198 - 209
      Abstract: This article presents an application of neural network-based Model Predictive Control (MPC) to improve the wind turbine control system’s performance in providing frequency control ancillary services to the grid. A closed-loop Hammerstein structure is used to approximate the behavior of a 5MW floating offshore wind turbine with a Permanent Magnet Synchronous Generator (PMSG). The multilayer perceptron neural networks estimate the aerodynamic behavior of the nonlinear steady-state part, and the linear AutoRegressive with Exogenous input (ARX) is applied to identify the linear time-invariant dynamic part. Using the specific structure of the Cascade Hammerstein design simplifies the online linearization at each operating point. The proposed algorithm evades the necessity of nonlinear optimization and uses quadratic programming to obtain control actions. Eventually, the proposed control design provides a fast and stable response to the grid frequency variations with optimal pitch and torque cooperation. The performance of the MPC is compared with the gain-scheduled proportional-integral (PI) controller. Results demonstrate the effectiveness of the designed control system in providing Frequency Containment Reserve (FCR) and frequency regulation in the future of power systems.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Improved Fault-Tolerant Model Predictive Torque Control of Five-Phase PMSM
           by Using Deadbeat Solution

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      Authors: Huanan Wang;Wenxiang Zhao;Hongyu Tang;Tao Tao;Suleman Saeed;
      Pages: 210 - 219
      Abstract: This paper proposes an improved fault-tolerant model predictive torque control (MPTC) for a five-phase permanent magnet synchronous motor based on deadbeat solution, which offers the reduced computation burden, good steady-state performance and simple control structure. Under the open-circuit fault condition, the virtual voltage vectors (VVV) which can restrain the harmonics work as the candidate vectors. The deadbeat solution is adopted to predict the reference voltage vector. The optimal VVV can be selected directly and rapidly according to the sector of the reference voltage vector. Hence the computation burden can be reduced largely because the process of testing all candidate VVVs is avoided. In order to reduce the error between the reference voltage vector and the selected VVV, a null vector is introduced by a simple geometric principle. Then, the duration of the selected VVV can be obtained. Therefore, the steady-state performance is enhanced because of the deadbeat solution and the multi-vectors in each control period. The experiments are presented to verify the proposed fault-tolerant MPTC.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Analytical Methodology for Modelling of Circulating Current Loss in
           Synchronous Electrical Machines With Permanent Magnets

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      Authors: Dmitry Golovanov;Chris Gerada;
      Pages: 220 - 231
      Abstract: This paper describes a novel analytical methodology for modelling winding copper losses as a result of circulating currents (CC) in permanent magnet synchronous machines (PMSM). CCs are important to be considered at an early design stage especially in high frequency and high performance machines where sub-optimal design choices can lead to significant alternating current (AC) losses. Nowadays mainly FEM method is used for precise calculation of circulating currents. However, it suffers on significant computational time required for building models and simulation of circulating current effect that makes it inapplicable for optimization purpose. The paper demonstrates the computationally efficient methodology through comparison with FEM based models for high power density PMSM with concentrated winding and validation against experimental results for a stator section at the fundamental frequency from 500 Hz to 2000 Hz. The methodology allows simulation of CC and AC Ohmic losses when machine supplied by any current waveforms, for arbitrary size and location of the conductors in the slots. A key novelty of the proposed method is the utilization of subdomain (SDM) approach in conjunction with solution of a system of ordinary differential equations (ODE) for an equivalent electrical circuit of machine windings. This approach is precise and fast but has never been used before for circulating current loss evaluation in windings of electrical machines. The model is intended to be used at the design stage of an electrical machine where multiple geometric dimensions, winding configurations and conductor placement in the slot are considered towards an optimal design.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Encoderless Parallel Predictive Torque Control for Induction Machine Using
           a Robust Model Reference Adaptive System

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      Authors: Haotian Xie;Fengxiang Wang;Yingjie He;José Rodríguez;Ralph Kennel;
      Pages: 232 - 242
      Abstract: This paper proposes a robust model reference adaptive system (MRAS) estimator incorporating online parameter identification algorithm for parallel predictive torque control (PPTC) scheme. In contrast to conventional predictive torque control (PTC), the proposed PPTC is designed to facilitate the determination of weighting factor that modifies the relative importance of the control objectives, by simultaneously evaluating the torque and flux tracking error terms. The weighting factor is fine-tuned via an adaptive selecting mechanism, to obtain the attractive feature of reduced torque and current tracking errors. Besides, an encoderless MRAS-based estimator is employed for rotor speed and stator flux estimation to reduce the hardware complexity. However, this proposed encoderless PPTC algorithm still suffers from weak robustness against inevitable disturbances caused by parameter variations, which is an important issue to be further investigated. In this paper, an encoderless MRAS estimator combined with online parameter identification algorithm is proposed as an effective solution to accurately estimate the rotor speed and predicted stator flux-linkage, that improves robustness against mismatched parameters for the proposed encoderless PPTC scheme. The feasibility of the proposed algorithm is verified through the obtained experimental measurements, that achieves precise speed tracking capability as well as reduced torque and current tracking errors.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Practical Implementation of a Hydro Power Unit Active Power Regulation
           Based on an MPC Algorithm

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      Authors: Mateo Beus;Hrvoje Pandžić;
      Pages: 243 - 253
      Abstract: Traditionally, proportional-integral-derivative (PID) based hydro turbine governors are mainly used due to their robustness and simple implementation. However, the weakness of these controllers is their design based on linear models and fixed parameters structure. This implies that the controller's parameters are usually calculated for the critical operating point leading to the controller's underperformance when operating away from the critical operating point. This paper introduces a Model Predictive Control (MPC) based hydro turbine's governor load/frequency controller whose linear prediction model parameters are updated depending on the operating point. The main intention of the paper is to reduce the gap between theoretical contributions and industrial practice. The experimental validation is achieved by implementing the introduced MPC algorithm to a laboratory hydro power plant's governor Programmable Logic Controller (PLC) and comparing its response with the responses of the gain-scheduled PI (GS-PI) controller, PI controller based on Particle Swarm Optimization (PSO-PI) and the controller based on exponential control law (EXP).
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • A P-Q Coordination Based Model Predictive Control for DFIG High-Voltage
           Ride Through

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      Authors: Changping Zhou;Zhen Wang;Huanhai Xin;Ping Ju;
      Pages: 254 - 263
      Abstract: This paper presents a P-Q coordination based model predictive control (MPC) for doubly fed induction generator (DFIG) to handle high-voltage ride through (HVRT) considering bipolar blocking of high-voltage direct current (HVDC) system. The overvoltage at the point of common coupling (PCC) after DC bipolar blocking and its sensitivity to current injection of DFIG is firstly analyzed based on a typical sending-end AC grid equivalent model. Then, the current feasible region of DFIG operation during overvoltage process is explicitly revealed considering generator and converter constrains. In the proposed HVRT control, a model predictive control (MPC) based method is developed where the minimum voltage tracking error is taken as the main objective function and the constrains are updated every control horizon based on real-time current feasible region. Through the rolling optimization and feedback correction framework, the rotor active and reactive currents of DFIG are coordinated and PCC voltage can be finally controlled to its target value to achieve HVRT. Further, the key MPC parameters are determined by solving an optimal problem to achieve better system robust stability and dynamic performances. Finally, the validity of the proposed control is verified by simulations in MATLAB/Simulink.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Average-Value Modeling of Direct-Driven PMSG-Based Wind Energy Conversion
           Systems

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      Authors: Qiufang Zhang;Jinghan He;Yin Xu;Zeqi Hong;Ying Chen;Kai Strunz;
      Pages: 264 - 273
      Abstract: Control design and stability analysis of direct-driven permanent magnet synchronous generator (PMSG)-based wind energy conversion systems (WECSs) typically involve extensive time-domain simulations and frequency-domain analyses. Those studies rely on accurate and computationally efficient models of WECSs. Detailed switching models can accurately describe the transients of power-electronic converters, but they suffer from low computational efficiency due to the repeated switching events. In this paper, a numerically efficient model is developed for a direct-driven PMSG-based WECS. Analytical and parametric average-value modeling techniques are applied to its switching subsystems, including a 12-pulse diode rectifier, a three-phase-interleaved boost converter, a dual three-phase voltage source inverter (VSI), and a crowbar circuit. The average-value models (AVMs) improve the simulation efficiency by representing the terminal characteristics of switching subsystems with a set of algebraic equations. In addition, numerical linearization techniques can be directly employed for them to obtain frequency-domain characteristics. The proposed model is verified against the detailed switching model and existing AVM in MATLAB/Simulink. It is shown to have excellent accuracy in both time-domain and frequency-domain studies while maintaining high computational efficiency.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Rotor Loss and Thermal Analysis of Synchronous Condenser Under
           Single-Phase Short-Circuit Fault in the Transmission Line

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      Authors: Guorui Xu;Zhenzhen Wang;Jingdi Zhou;Zhiqiang Li;Yang Zhan;Haisen Zhao;Weili Li;
      Pages: 274 - 285
      Abstract: A synchronous condenser (SC) can provide the reactive power for the Ultra High Voltage Direct Current (UHVDC) converter station to keep voltage stability and prevent commutation failure. The single-phase short circuit at a transmission line is prevalent and it can result in not only the voltage drop but also the increase of the rotor loss and temperature of the SC. In order to study the ability of the SC to withstand a single-phase short-circuit fault, the rotor loss and temperature field of a 300-MVar SC are studied by coupling the electromagnetic and temperature field models of the SC with the models of the electric circuit and power grid. The loss distributions in the rotor core and slot wedges are calculated under a single-phase short-circuit fault at the different positions of the transmission line. The rotor temperature distributions of the SC under over- and under-excitations are calculated and verified by the experiments. The influence of short-circuit duration on the rotor temperature of the SC is calculated under the single-phase short circuit. The study can provide a theoretic basis for the improvement of the operating ability of the SC under the single-phase short-circuit faults.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • A Novel Adaptive Filtering Algorithm Based Parameter Estimation Technique
           for Photovoltaic System

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      Authors: Mohammed H. Qais;S. M. Muyeen;
      Pages: 286 - 294
      Abstract: This paper offers a hybrid analytical and estimation based technique to determine the photovoltaic (PV) system parameter in a systematic way. The new model formulation is based on the datasheet parameters under standard test condition and normal operating cell temperature environment, forming the analytical approach's foundation. The estimation part is based on the adaptive filtering algorithm, which shows superiority in estimated parameters compared to existing techniques applied in the photovoltaic system. The proposed approach is made available for a single diode PV model and scaled up aggregated model in extracting the model parameters of two real PV modules in the market, representing the exact I-V characteristics of the manufacturer datasheet. A rigorous comparative analysis is carried out between two adaptive and two optimization based estimations for performance evaluation and recommendation purposes.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Iron Loss Analysis in Axial Flux Permanent Magnet Synchronous Motors With
           Soft Magnetic Composite Core Material

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      Authors: Reemon Z. Haddad;
      Pages: 295 - 303
      Abstract: Accurate calculation of iron losses in electric machines are essential for optimal machine design. This is especially important for axial flux permanent magnet motors with solid stator and rotor cores. This paper investigates iron losses in axial flux motor with soft magnetic composite material for the stator and the rotor. First, an analytical model is proposed to estimate iron losses under different operating conditions. The model is based on combining the Quasi 3-D computation approach and the magnetic equivalent circuit. The proposed model can be modified to account for different motor topologies and different stator and magnet designs. Then, The effect of torque ripple, on iron losses, is studied by comparing two motors: an optimized motor, with dummy pocket added to the stator tooth, and a non-optimized motor. Finally, the effect of the motor control scheme and the inverter switching frequency is studied by implementing two controllers: the Field Oriented Control and the Trapezoidal control. Simulations using 3-D finite element analysis and experimental tests are conducted, under different operating conditions, on two $text{12},V$, 6 slots, 8 poles single stator single rotor fractional horsepower axial flux permanent magnet synchronous motor prototypes. Test results shows that motor optimization, the choice of the motor control scheme, and the selected switching frequency can significantly affect iron losses in the motor. Using an optimized motor with a smooth control scheme, such as Field Oriented Control, and a high switching frequency, can cause a variation in iron losses by around 14% compared to a non optimized motor with the Trapezoidal control and a low switching frequency.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Torque and Radial Force Optimization of Arc Flux Switching Permanent
           Magnet Linear Motor Used for Large Scanning Equipment

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      Authors: Fei Liu;Jianhui Hu;Yong Li;
      Pages: 304 - 315
      Abstract: This paper deals with the analysis and comprehensive optimization of the torque and radial force ripples in the arc flux switching permanent magnet linear motor, which is equipped in the large scanning equipment. The torque ripple is caused by the no-load torque including cogging torque and end force. Specially, a worth noting problem of unbalanced radial forces is caused by the discontinuity of the arc stator, which is easily behaved as the rotor and load vibrations. In this paper, an analytical model based on the magnetic permeance function is established to analyze the principle of the no-load torque and radial force. Based on it, the optimization goal of force harmonics can be determined, and the feasible optimization approach can be predicted. It demonstrates the harmonic distribution of the torque is completely opposite to that of the radial force. Pure structural parameter optimization can not achieve the satisfactory results. To effectively suppress the no-load torque and radial force at the same time, a novel structure with two sets of specially arranged three-phase stator is proposed. An obvious optimization effect is verified according to the detailed FEM and experiment analysis.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Multiple Model Adaptive Estimation of the Aerodynamic Torque for the
           Control of Variable Speed Wind Turbines

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      Authors: Dimitris Bourlis;
      Pages: 316 - 326
      Abstract: Closed loop control of the rotor angular speed of variable speed wind turbines in below rated operation area has been of particular research interest as a means of improving their power conversion efficiency. Quite promising approaches are based on tracking of the optimum rotor angular speed reference, which depends on the effective wind speed that can be calculated from the estimated aerodynamic torque of the rotor. For this purpose, Kalman filtering has been proposed, due to the stochastic dynamics involved. However, there are challenges on the proper selection of the process noise covariance in the Kalman filter, due to the nonstationary wind statistics. In this paper, an effective solution to overcome these challenges is proposed, using the multiple model adaptive estimation method. As shown from hardware-in-loop simulation results with real wind turbine and wind data, this method effectively tackles the uncertainty in the process noise covariance and exhibits remarkable estimation accuracy under all wind conditions.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Core Loss Estimation for an Inverter-Fed Induction Motor With More
           Accurate Realisation of Material Non-Linearity and Impact of Hysteresis
           Minor Loops

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      Authors: Rajendra Kumar;Praveen Kumar;
      Pages: 327 - 336
      Abstract: The work presents a fast and accurate core loss evaluation method for inverter-fed induction machines. The proposed method takes into account the influence of time variation of magnetic permeability on the eddy current loss. Furthermore, the proposed method presents an accurate approach to precisely evaluate the hysteresis loss. The results obtained from the proposed method are compared with the existing methods for a 1.5 kW inverter-driven induction motor. The method shows sufficiently high accuracy with reduced complexity and implementation-time for a wide range of inverter switching frequency and motor’s loading.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Fault-Tolerant Operation of a Six-Phase Permanent Magnet Synchronous Hub
           Motor Based on Model Predictive Current Control With Virtual Voltage
           Vectors

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      Authors: Xiaodong Sun;Teng Li;Xiang Tian;Jianguo Zhu;
      Pages: 337 - 346
      Abstract: This paper proposes a model predictive current control (MPCC) compensation method based on virtual voltage vectors for single-phase open-circuit faults of an asymmetric six-phase permanent magnet synchronous hub motor (PMHSM). The proposed strategy adopts the normal vector space to decompose the transformation matrix without reconfiguring the controller topology. By analyzing the difference between the open-circuit phase voltage and the state of health, the disturbance term of the prediction vector in the α-β and x-y subspaces is obtained. 64 voltage vectors are obtained from the switching states of the 6-phase two-level inverter, and then these 64 voltage vectors are appropriately compensated and synthesized into 24 new virtual voltage vectors. The new virtual vectors avoid the adjustment of the MPCC weighting factors and the synthesized virtual vectors can suppress current harmonics. Finally, the experimental results show the effective performance of the method before and after the fault-tolerant operation.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Improved Cross-coupling Effect Compensation Method for Sensorless Control
           of IPMSM With High Frequency Voltage Injection

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      Authors: Bo Shuang;Z. Q. Zhu;Ximeng Wu;
      Pages: 347 - 358
      Abstract: In this paper, the conventional cross-coupling effect compensation method that uses offline measured cross-coupling factor by current compensation in high frequency pulsating voltage injection based sensorless control is firstly extended for use in high frequency rotating voltage injection based sensorless control by angle compensation. Compared with the current compensation method, the angle compensation method has better dynamic performance as confirmed by experiments. To enable direct angle compensation, a novel method for offline measuring the cross-coupling induced errors is proposed by injecting HF voltages in d-axis and q-axis, respectively. The measured errors can be used for online cross-coupling effect angle compensation irrespective of the injected signal that is used for position estimation. Experiments have verified the effectiveness of the proposed methods. In addition, stability and convergence of sensorless operation with the proposed cross-coupling effect compensation methods at highly saturated conditions are also analyzed and experimentally evaluated.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Online Airgap Flux Based Diagnosis of Rotor Eccentricity and Field Winding
           Turn Insulation Faults in Synchronous Generators

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      Authors: Muhammad Faizan Shaikh;Han-ju Kim;Sang Bin Lee;Chaewoong Lim;
      Pages: 359 - 366
      Abstract: Rotor faults in a synchronous generator severely deteriorate its performance, reducing the operation efficiency and reliability. Most of the field-wide accepted methods require stoppage of generator operation and disassembly, and online diagnosis of rotor faults is difficult due to the lack of dependable online methods for sensitive rotor fault detection. Therefore, online methods that can reliably and unambiguously detect rotor field winding and eccentricity faults before they lead to machine failure are required. This paper presents a new method for detecting and distinguishing rotor field winding insulation and eccentricity faults online during synchronous generator operation based on measurements from airgap flux probes, which are installed in most synchronous generators used for electric power generation. A non-complex, time domain analysis method is proposed which makes use of the voltage induced in the airgap flux sensor for a reliable prediction of the presence and identification of rotor field winding turn insulation failure and rotor dynamic eccentricity. The method is tested and verified experimentally on a 5 hp synchronous generator and on measurements from a 330 MW pumped storage generator.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Reduction of Switching Frequency Vibration of Induction Machines by
           Auxiliary Winding With Capacitors

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      Authors: Shichong Xia;Shanming Wang;
      Pages: 367 - 376
      Abstract: The switching action of power electronic devices causes high frequency current, magnetic field, vibration and annoying noise of induction machines fed by inverters, and these high-frequency components concentrate around the switching frequency and its multiple times. Adding auxiliary winding with capacitors is an effective way to reduce the high frequency vibration by weakening the high frequency magnetic field. In order to analyze the vibration mitigation effect of adding auxiliary winding with capacitors, this method is systematically and theoretically analyzed in the paper. The accurate equivalent circuit of induction machines with auxiliary winding is proposed considering the mutual leakage inductance between stator main winding and auxiliary winding. The transfer function of electromotive force and its frequency response are used to illustrate the effect of vibration reduction. To verify the correctness of the analysis, two induction machines with different auxiliary winding arrangements are prototyped and tested.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • DC Fault Study of a Point-to-Point HVDC System Integrating Offshore Wind
           Farm Using High-Temperature Superconductor DC Cables

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      Authors: Wang Xiang;Weijia Yuan;Lie Xu;Eoin Hodge;John Fitzgerald;Paul McKeever;Keith Bell;
      Pages: 377 - 388
      Abstract: This paper presents a feasibility study of an offshore wind farm (OWF) HVDC integration system using high-temperature superconductor (HTS) DC cables. A representative ±100 kV/2 GW point-to-point OWF HVDC system is proposed including HTS DC cables and two converter stations using modular multilevel converters (MMCs). To be compatible with the high current rating of the HTS cables, each of the offshore and onshore converter stations consists of three MMCs in parallel. To study the interaction between HTS DC cables and MMCs, a multiple lumped π-section model of a HTS DC cable considering electrical and thermal functionality is developed. This paper provides a critical assessment of the proposed HVDC-HTS system, with emphasis on the performance under fast DC fault transients. Detailed simulations presented in this paper reveal that the HVDC-HTS system provides effective current limiting against DC cable short circuit faults.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Performance of Urban Water-Pipeline Energy Harvester System Considering
           Electromagnetic-Mechanical Design

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      Authors: Sarbajit Paul;Junghwan Chang;Deokje Bang;
      Pages: 389 - 402
      Abstract: This paper proposesthe design process and performance of an Urban Water-pipeline Energy Harvester (UWEH) System. The UWEH system design is broadly divided into two parts, namely, the electromagnetic and mechanical subsections modeling. The electromagnetic modeling includes the selection, design, prototyping and performance testing of a 65-kW permanent magnet synchronous generator (PMSG) which runs at the rated speed of 500 rpm. The mechanical modeling includes the installation, bearing selection, propeller system integration and waterproof sealing mechanism of the whole UWEH system for the field test. Detailed information on practical implementation is highlighted. Finally, based on the lessons learned from the problem associated with the mechanical subsection, a bearing-less buoyant rotor mechanism is proposed explaining its airgap control mechanism.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • A Nonlinear Model Based Analysis and Accurate Design of Ultracapacitor
           Stack for Energy Storage Systems

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      Authors: P. Roja;D. Venkatramanan;Vinod John;
      Pages: 403 - 412
      Abstract: Sizing of ultracapacitor (UC) stack is an essential requirement in the design of energy storage systems (ESS), which are widely deployed today in varied power conversion applications. Unlike a linear capacitor that displays constant capacitance characteristics over the operating voltage range, UCs exhibit considerable nonlinearity in the form of voltage-dependent capacitance and display notable variation in characteristics during operation. Analyzing the behavior of the overall UC bank that consists of several stacked nonlinear UC cells and evaluating its effective capacitance is therefore critical. In this paper, an exact-analysis framework is presented for characterizing the nonlinear behavior of the overall UC stack. Closed-form expressions for the UC stack’s effective voltage-dependent capacitance, terminal voltage characteristics, and stored energy are derived as a function of unit cell nonlinear parameters and the number of series-parallel cells, using which the deviations in the UC stack behavior from the linear characteristics are analytically captured. It is shown, owing to the linear model of the UC employed in existing design methods, that the resultant stack will either be (a) over-sized and expensive, or (b) insufficient to meet the ride-through specifications in practice as the inherent nonlinearity is ignored. To address these limitations, an improved UC stack design method is proposed based on the nonlinear UC model, which not only optimizes the size of the UC stack, but also guarantees that the ESS specifications are accurately met. Experimental results on two UC stack hardware prototypes validate the accuracy of the proposed nonlinear analysis and the improved design method for ride-through applications.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Improved Low-Order Thermal Model for Critical Temperature Estimation of
           PMSM

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      Authors: Jianghua Feng;Dawei Liang;Z. Q. Zhu;Shuying Guo;Yifeng Li;Anfeng Zhao;
      Pages: 413 - 423
      Abstract: The low-order lumped parameter thermal models (LPTMs) are one of the most competitive online approaches to estimate the critical temperatures in electrical machines. Firstly, this paper explores the correlation between the conventional high-order and low-order LPTMs and then presents some critical modelling guidelines of low-order LPTM together with an improved four-order LPTM. Secondly, a simple dynamic quasi-linear model (DQM) is proposed to define convection thermal resistances, which can be used in both conventional high-order and low-order LPTMs. The application of DQM can improve the estimation accuracy by indirectly introducing more degrees of freedom, which is especially beneficial for the magnet temperature estimation in the low-order LPTM due to its highly abstract rotor thermal modelling. Finally, a prototype permanent magnet synchronous machine is used for experimental validation under different operation profiles.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Design of a Novel PM-Assisted Synchronous Reluctance Motor Topology Using
           V-Shape Permanent Magnets for Improvement of Torque Characteristic

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      Authors: Ali Mohammadi;Seyyed Mehdi Mirimani;
      Pages: 424 - 432
      Abstract: This paper presents the design and analysis of a novel topology for a Permanent Magnet Assisted Synchronous Reluctance Motor (PM-assisted-SynRM). The proposed topology presents a simple structure that incorporates the assistance of an internally inserted V-shape permanent magnet (IVPM) machine and also a Synchronous Reluctance Machine (SynRM). The main novelty in this paper is that, the permanent magnets in the rotor are diverted so that the reluctance component of the torque and the magnetic component of the torque reach their maximum values at the same load angle that can eventually leads to a higher output torque in the same volume. To further highlight the advantages of the proposed topology to the conventional topologies, its characteristics including, air gap flux density, electromagnetic torque, and back electromotive force (Back-EMF), are compared to a conventional PM-assisted-SynRM. The key improvement of the proposed topology is that, it features a higher torque density while consuming fewer amounts of permanent magnets which is very beneficial in mass productions. Finally, by using the finite-element-analysis (FEA), the Von Mises stress for the proposed topology in different rotational speeds shows its capability in handling mechanical stresses and the experimental results validate the characteristics of the proposed topology.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Robust Predictive Rotor Current Control of a Doubly Fed Induction
           Generator Under an Unbalanced and Distorted Grid

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      Authors: Yongchang Zhang;Tao Jiang;
      Pages: 433 - 442
      Abstract: Under unbalanced and distorted grid conditions, the performance of conventional control methods for doubly fed induction generators (DFIGs) severely deteriorates, resulting in highly distorted stator and rotor currents. Furthermore, the performance can further degrade when the machine parameters used in such a controller differ from their actual values due to temperature, saturation and so on. To solve these problems, this paper proposes a robust predictive rotor current control (R-PRCC) scheme for a DFIG with multiple aims, even under unbalanced and distorted grid conditions. First, the reference value of the positive-sequence component of the rotor current is obtained from the outer power loop with the help of cascaded delayed signal cancellation (CDSC), which ensures the control aim of sinusoidal and balanced rotors currents. By investigating the relationship between stator currents and rotor currents, a new rotor current reference without using DFIG parameters can be obtained to satisfy multiple control aims, including sinusoidal and balanced stator currents, constant output active power and constant electromagnetic torque. Second, by introducing an extended state observer (ESO), the total disturbance caused by model uncertainty can be quickly estimated, and deadbeat control is further incorporated to achieve fast and accurate control of the rotor current. The proposed R-PRCC scheme is compared to conventional field-oriented control (FOC) and model predictive rotor current control (MPRCC). Simulated and experimental results are obtained for a 1.5-kW laboratory. The DFIG system confirms the effectiveness of the proposed method.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Coupled Fluid-Solid Heat Transfer of A Gas and Liquid Cooling PMSM
           Including Rotor Rotation

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      Authors: Likun Wang;Yuan Li;Fabrizio Marignetti;Aldo Boglietti;
      Pages: 443 - 453
      Abstract: In order to study the problem of the high temperature reached by the end windings, caused by the high current in the armature windings of permanent magnet synchronous motors (PMSM), a 560 kW gas and liquid cooling PMSM used for a compressor is analyzed. The heat source is obtained by a two-dimensional numerical analysis of the electromagnetic field. A three-dimensional fluid-solid coupling heat transfer model is established. Under the action of the cooling medium, one-quarter of the PMSM structure is numerically simulated. The temperature distribution of the 560 kW PMSM is studied, including rotor rotation. The temperature distribution of the PMSM armature winding and the distribution of fluid around the winding under different inlet air flow speeds are analyzed. The calculated values of the end winding temperature at different currents are compared with the experimentally measured values. The rationality of the three-dimensional fluid-solid coupling heat transfer model and the correctness of the calculation method are verified. This paper provides both the analysis and the computation scheme of the fluid-solid heat transfer of the PMSM.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Customized PMSM Design and Optimization Methodology For Water Pumping
           Applications

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      Authors: Carlos Candelo-Zuluaga;Jordi-Roger Riba;Antonio Garcia Espinosa;Pere Tubert Blanch;
      Pages: 454 - 465
      Abstract: The need to reduce water pumps size to achieve compact designs adapted to multiple working points opens new fields of study. PMSMs are the preferred choice due to outstanding torque-speed range capabilities. This paper presents a methodology to design and optimize PMSMs by defining the desired torque-speed-efficiency map, adapting its performance to the hydraulic characteristics of the water pump. Once the hydraulic efficiency is known, an initial PMSM reference torque-speed-efficiency map is defined according to the objective motor performance, including the distribution of power losses and the power rating of the selected application. The designer has full freedom to define the efficiency levels and distribution along the torque-speed map. The design optimization algorithm achieves the PMSM characteristics which adjust as much as possible to the defined performance. This methodology uses ultra-fast finite element analysis by applying magneto-static computations and a time-space conversion to compute the iron losses, reducing the computational requirements. The torque-speed-efficiency map is calculated by applying a direct-quadrature electrical model. The objective function uses a novel image comparison technique that allows comparing the similarity between the objective and optimized maps. The methodology is validated experimentally by designing and testing a PMSM adapted to a real WP application.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Bearing Fault Event-Triggered Diagnosis Using a Variational Mode
           Decomposition-Based Machine Learning Approach

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      Authors: Houssem Habbouche;Yassine Amirat;Tarak Benkedjouh;Mohamed Benbouzid;
      Pages: 466 - 474
      Abstract: The monitoring of rolling element bearing is indexed as a critical task for condition-based maintenance in various industrial applications. It allows avoiding unscheduled maintenance operations while decreasing their cost. For this purpose, various methodologies were developed to ensure accurate and efficient monitoring. In this context, this paper proposes an approach for bearing fault early diagnosis based on the variational mode decomposition (VMD), used as a notch filter for dominant mode cancellation, and a machine learning approach, namely the one-dimensional convolution neural network (1D-CNN), for detection and diagnosis purposes. Specifically, the proposed approach first performs features extraction using VMD for fault detection, and then triggers to multi-scale features extraction using CNN convolution and pooling layers for classification and diagnosis. The proposed bearing fault detection and diagnosis approach is evaluated, in terms of robustness and performances, using the well-known Case Western Reserve University experimental dataset. In addition, performances are evaluated versus well-established demodulation techniques, in terms of fault detection, and machine learning strategies, in terms of fault diagnosis. The achieved results show that the proposed VMD notch filter-based 1D-CNN approach is clearly promising for bearing degradation monitoring.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Mathematical Analysis Model of Double-Stator Field Modulation HTS Machine
           Based on General Airgap Field Modulation Theory

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      Authors: Xinkai Zhu;Ming Cheng;Yubin Wang;Wei Hua;Peng Han;Wei Wang;
      Pages: 475 - 486
      Abstract: TheSuperconducting (SC) machines have the merits of higher power and torque density due to the fact of higher electrical or magnetic loading. Especially, the field modulation SC machine (FMSCM) recently attracts more and more attention from scholars, since this kind of SC machines successfully overcome the drawbacks of the traditional SC synchronous machines, such as the rotating seal of the coolant and the electrical brush-slip-ring for current transfer. However, the research method of the FMSCM mainly adopts the finite element analysis (FEA). Although the FEA can provide accurate results, the time consumption is huge, particularly at the initial design of the large capacity FMSCM, the time cost will be unacceptable. Aiming at solving this problem, this paper attempts to establish the mathematical analysis model of a double-stator field modulation HTS machine (DSFM-SCM) using a new theory of electrical machine, i.e., general airgap field modulation theory, for the first time. Both the FEA and experiments are carried out on the DSFM-SCM, to verify the effectiveness of the proposed mathematical analysis model. Although there is discrepancy between the proposed analytical method and FEA, it can basically meet the requirement at the initial design, and sufficiently exhibit the modulation effect of geometric structure, reflecting the essential mechanism of the DSFM-SCM. In addition, it is worth noting that the establishment process of analytical model of the DSFM-SCM can provide reference for the other FMSCMs.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Hybrid Excitation PM Synchronous Motors: Part I – Per Unit Analysis

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      Authors: Daniele Michieletto;Luca Cinti;Nicola Bianchi;
      Pages: 487 - 494
      Abstract: A synchronous machine is analysed, characterised by a rotor including both Permanent Magnets (PMs) and excitation winding. The PMs produce a fixed flux while the excitation winding is adopted to modulate the rotor flux. The nominal point and flux-weakening performance of such a synchronous machine is compared to that of a more commonly used PM machine, to the aim of highlighting advantages and drawbacks. For the sake of achieving a more general comparison, a per unit system is introduced. Thanks to this normalization all the combinations of the machine parameters are taken into account, for both standard PM and HEPM machine. Fixing the same performance at nominal speed, it is shown that the HEPM machine exhibits a higher capability and power factor equal to one during flux-weakening operations. The possibility to modulate the rotor flux allows to overcome the speed limit of the standard PM machines and to keep a high torque and power in a wide range of speeds.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Hybrid Excitation PM Synchronous Motors: Part II — Finite Element
           Analysis

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      Authors: Daniele Michieletto;Luca Cinti;Nicola Bianchi;
      Pages: 495 - 504
      Abstract: This paper deals with the finite element analysis of Hybrid Excitation Permanent Magnet Synchronous Motors, that is, synchronous motors characterised by a rotor including both permanent magnets and an excitation winding. Such a winding is adopted to modulate the rotor flux so that the motor exploits the maximum torque for any operating speed. The higher benefit is obtained at speeds higher than the nominal speed, i.e. during the flux weakening operations. Thus the focus is to determine the performance of different topologies of hybrid excitation PM synchronous motors, considering compared to those achieved with a standard interior PM synchronous motors. The possibility to vary the rotor flux in the hybrid excitation PM motors allows to design the motor with a high no-load flux linkage, necessary to get high torque at low speeds, and to get high torque in a wide speed range.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • A Single-Stage Rectifier-Less Boost Converter Circuit for Piezoelectric
           Energy Harvesting Systems

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      Authors: Mahesh Edla;Yee Yan Lim;Deguchi Mikio;Ricardo Vasquez Padilla;
      Pages: 505 - 514
      Abstract: In this paper, a single-stage rectifier-less boost converter circuit (SSRBC) for piezoelectric energy harvesting from ambient vibration was proposed. The proposed rectifier-less circuit acted as a boost converter to extract energy from a piezoelectric device (PD). It combined the conventional boost, buck-boost methods using two split inductors and single filter capacitor. The proposed integrated circuit topology functioned in both positive and negative half cycles generated by the PD. In the proposed topology, inductors were invigorated by being enveloped with the current, which was produced by the PD through the switches. This facilitated active rectification of ultra-low AC (amplitude < 0.5 VP). Theoretical analysis, control strategies, simulation and experimental study were presented. The proposed circuit was capable of converting a low amplitude AC voltage of 0.5 VP into 5.1 Vdc. The highest output power extracted by the proposed circuit was 281.1 μW, which outperformed existing circuits. It could potentially facilitate the advancement of vibration-based energy harvesting systems for low power demand applications such as sensors, quartz watches and portable charging devices.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Estimation of 3-D Magnet Temperature Distribution Based on
           Lumped-Parameter and Analytical Hybrid Thermal Model for SPMSM

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      Authors: Dawei Liang;Z.Q. Zhu;J.H. Feng;S.Y. Guo;Y.F. Li;A.F. Zhao;J.W. Hou;
      Pages: 515 - 525
      Abstract: This paper presents a hybrid analytical thermal model by utilizing the synergies of the lumped-parameter thermal model (LPTM) and the analytical thermal model to estimate the 3-dimensional (3-D) permanent magnet (PM) temperature distribution as well as the hotspot for surface-mounted PM synchronous machines (SPMSMs). The hybrid analytical thermal model is firstly developed based on 2-dimensional analytical models in radial-circumferential and radial-axial planes, and then extended to three dimensions, in which the uneven distributions of PM eddy current loss are taken into account. The analytical solutions are obtained by solving the Poisson's equations under the Dirichlet and the convection boundary conditions, which are extracted from the synergized LPTM. The proposed hybrid thermal model is applied to a totally enclosed SPMSM and validated by the 3-D electromagnetic-thermal coupled finite element method and experiments.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Design Optimization of High Temperature Superconducting Magnets and
           Null-Flux Coils for Electrodynamic Suspension Train

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      Authors: Tianyong Gong;Guangtong Ma;Jing Li;Zhengwei Zhao;Ruichen Wang;
      Pages: 526 - 536
      Abstract: The introduction of high temperature superconducting (HTS) magnet, which is capable of working at liquid nitrogen temperature, and the use of null-flux coil, make the liquid-helium-free electrodynamic suspension (EDS) train available. In essence, the electromagnetic force of a superconducting EDS train is generated by electromagnetic interaction between the onboard superconducting magnets and the ground null-flux coils. In order to obtain an efficient HTS EDS train, the design optimization of the HTS magnets and null-flux coils is indispensable. This study is devoted to this aspect. We first establish an improved load-line method for efficiently estimating the critical current of HTS magnets and an improved semianalytical model to accurately calculate the induced currents and electromagnetic forces in the EDS train. Based on above two improvements, the onboard HTS magnets and corresponding null-flux coils are then designed and optimized to enhance the overall performances of the HTS EDS train. At final, according to the optimized results, the HTS magnets and null-flux coils were manufactured and measured, followed by the performance analyses of the obtained HTS EDS train. The results have shown that the electromagnetic performances of the designed HTS EDS train are excellent, demonstrating the effectiveness of the optimization methodology.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Improvement of Steady State Performance for Rotating Vector-Based Direct
           Torque Control

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      Authors: Weitao Deng;Shanhu Li;
      Pages: 537 - 546
      Abstract: Matrix converter (MC) rotating vector (RV) has the natural advantage for common-mode voltage (CMV) minimization. However, the application of RV in direct torque control (DTC) strategy for motor drive system is limited, mainly due to the extensive torque ripple and current distortion. To improve the steady state torque and current performance of the traditional RV-based DTC, a novel RV- based DTC method is proposed in this paper. According to the analysis of the angle offset between stator flux and the candidate voltage vector, the vector plane is divided into 12 sectors, and virtual vector synthesized by two adjacent rotating vectors is employed to fill in the blank sectors. Based on this, a 12 sector- switching table combined with a novel mapping table of rotating vectors are established to fulfill the proposed RV-DTC method. Experiments are carried out to verify the proposed method. The results show that compared with the traditional RV-DTC, steady state torque and current performances are evidently improved with the proposed RV-DTC at approximate switching frequency, while zero CMV is reserved.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Generic Multi-Frequency Modelling of Converter-Connected Renewable Energy
           Generators Considering Frequency and Sequence Couplings

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      Authors: Behnam Nouri;Łukasz Kocewiak;Shahil Shah;Przemyslaw Koralewicz;Vahan Gevorgian;Poul Sørensen;
      Pages: 547 - 559
      Abstract: Frequency and sequence couplings can compromise the trustworthiness of multi-frequency models for converter-based systems. There have been effective attempts to address the couplings mainly by linearized averaged models. Only a few studies have been conducted on practical optimization of such models with enormous matrices and experimental results. This paper provides a generic theory for coupling patterns and proposes a multi-frequency modelling method to detect and address only the main couplings in the sequence domain for converter-connected renewable energy generators. The proposed generic model is based on empirical tests using small-signal perturbations and adopting Fourier transform on the switching converter response. The proposed theory and modelling methodology are verified using a 7MVA grid emulator for voltage perturbation tests on a 2MVA photo-voltaic converter. Accordingly, the couplings can exist in more generic forms, including multiples of perturbation and fundamental frequencies. To the best of our knowledge, the patterns with the multiples of the perturbation frequency have been overlooked in the literature. Furthermore, the mirror frequency concept is valid for all coupling patterns and is included in the proposed model. Besides, the proposed patterns and the environment noise levels have been practical criteria for selecting the main couplings.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • A Comprehensive Robust Techno-Economic Analysis and Sizing Tool for the
           Small-Scale PV and BESS

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      Authors: Ahmed A.Raouf Mohamed;Robert J. Best;Xueqin Liu;D. John Morrow;
      Pages: 560 - 572
      Abstract: Battery energy storage systems (BESS) are receiving great attention due to their ability in maximizing self-consumption and energy arbitrage. However, in many countries, BESS profitability is still questionable without subsidy due to their high capital costs. This paper proposes an open-source generic tool to provide comprehensive techno-economic analysis on the small-scale PV/BESS. The proposed tool utilizes real-time BESS control method that has been validated using real experimental measurements in addition to integrating a reliable degradation model to determine the loss in savings due to capacity degradation. The profitability is investigated by conducting different cost-benefit analyses for the PV and BESS. An optimization layer is introduced to find the optimal PV/BESS sizes that boost investment profitability by maximizing the net present value. A detailed case study is presented for a household in the U.K. under three different tariff structures that consider practical parameters and assumptions. Furthermore, sensitivity analyses are performed to evaluate the impact of the cost-benefit analysis assumptions on the PV/BESS sizing and profitability. Finally, the BESS investment viability is investigated over the next few years for different investment expectations to answer the question of when the BESS should be installed to be a viable economic-attractive option in the U.K.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Impedance Modelling Mechanisms and Stability Issues of Single Phase
           Inverter With SISO Structure and Frequency Coupling Effect

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      Authors: Zhengzhao Li;Miao Zhu;Chuanchuan Hou;Han Wang;Yunwei Li;Xu Cai;
      Pages: 573 - 584
      Abstract: Multi-Input and Multi-Output (MIMO) impedance model considering the Mirror Frequency Effect (MFE) has been studied for single phase systems in the past five years. However, the resulting impedance matrix is mathematically intractable without practically physical meaning. Besides, another unique High Frequency Effect (HFE) existed only in single phase systems has received less attention. To tackle these problems, this paper presents a Single-Input and Single-Output (SISO) modeling mechanism for single phase inverter considering both MFE and HFE. Firstly, the accurate response of T/4 delay PLL is derived in this paper. Then, based on the harmonic linearization method, the inverter impedance model is successfully realized in the SISO structure, where MFE and HFE are represented by two additional impedance. And consequently, the influence of HFE on inverter impedance is analysed with varying PLL bandwidth. Applying the Nyquist criteria, the proposed overall impedance model can precisely predict the sub/super-synchronous oscillation that occurs in the weak grid. Finally, all the theoretical analysis results are validated by simulation cases. The proposed work could significantly simplify the traditional MIMO modeling procedure with a more straightforward impedance structure, which might be helpful for solving potential oscillation issues of renewable energy integration.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • High Speed Synchronous Reluctance Machines: Modeling, Design and Limits

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      Authors: Gianvito Gallicchio;Mauro Di Nardo;Marco Palmieri;Alessandro Marfoli;Michele Degano;Chris Gerada;Francesco Cupertino;
      Pages: 585 - 597
      Abstract: An important barrier to the adoption and acceptance of synchronous reluctance (SyR) machines in different applications lies in their non-standardized design procedure. The conflicting requirements incurring at high speeds among electromagnetic torque and structural and thermal limitations can significantly influence the machine performance, leading to a real design challenge. Analytical models used for design purpose lack in accuracy and force the designer to heavily rely on finite element analysis (FEA), at least during the design refinement stage. This becomes even more computationally expensive as the speed increases, as the evaluation of the rotor structural behaviour is required. This work presents a computationally efficient hybrid analytical-FE design process able to consider all the main limiting design aspects of SyR machine incurring at high speed, namely structural and thermal. As a vessel to investigate the proposed design routine accuracy, several high speed SyR machines have been designed for a wide range of operational speeds (up to 70 krpm). The thermal and mechanical factors limiting the high speed operation are deeply analyzed aiming at maximize the mechanical output power. The proposed design approach is then validated by comparison against experimental measurements on a 5 kW-50 krpm SyR prototype.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Development of Dual Armature-Winding Four-Phase Variable Flux Reluctance
           Generator for Fault-Tolerant Capability Improvement

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      Authors: Yao Zhao;Denghui Teng;Dongdong Li;Yang Mi;Xing Zhao;
      Pages: 598 - 611
      Abstract: In this paper, a four-phase 8/10-pole dual armature-winding variable flux reluctance generator (DAW-VFRG) with double-redundant rectifier circuit is proposed for onboard generator. The proposed generator integrating four-phase VFRG and dual armature winding structure improves fault-tolerant capability and power density. Based on the airgap field harmonics analysis and winding function theory, the no-load back-EMF model and winding inductance model are deduced for determining the optimal stator/rotor pole combination. In addition, based on magnetic energy comparison, the influence of the connection categories between two sets of armature windings and rectifier circuits on output capability is also investigated when the saturation effect is considered. The key design parameters are globally optimized to improve the output capability and fault-tolerant capability simultaneously. Moreover, the electromagnetic performance of the proposed DAW-VFRG under both normal and fault condition is evaluated and compared with single armature-winding VFRG with half bridge rectifier. Finally, two prototypes are manufactured and tested to validate the finite-element predictions.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • A New Hybrid Voltage Source Converter With Reduced Active Switch Count for
           HVDC Applications

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      Authors: Dereje Woldegiorgis;H. Alan Mantooth;
      Pages: 612 - 622
      Abstract: This paper presents a new hybrid voltage source converter topology with reduced active switch count for HVDC applications. It consists of a block of switches in the upper converter arms and cascaded switch-diode cells in the lower converter arms. The cascaded switch-diode cells in the lower converter arms produce a multilevel output voltage while the switch blocks in the upper converter arms perform rectification. The switches in the upper converter arms conduct for one-third of the fundamental line period as dictated by the relative magnitude of the input line-to-neutral voltages. Only one of the three phase blocks of switches conduct at a time. Compared to other voltage source converter topologies with similar structure and operation to this topology, the proposed topology has lower number of devices. Therefore, it has lower converter footprint and cost. More importantly, it reduces the semiconductor device power losses significantly due to the lower number of active switches (lower switching loss) and the lower number of devices in current conduction path (lower conduction loss). The basic operation principle of the proposed converter and its associated control strategy that regulates the power exchange between the converter, and the ac and dc networks are described in detail and verified using both simulation and experimental results.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Practical Improvements to Generator Parameter Validation Using
           Stator-Decrement Test

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      Authors: Quincy Y. Wang;Song Wang;
      Pages: 623 - 630
      Abstract: This article discusses the accuracy issue in applying the commonly used stator-decrement test (load rejection) method for validating generator d-axis parameters. Theoretical analysis and actual examples are provided to illustrate how the accuracy issue is related to the rotor field winding current as well as hysteresis, which has not been analyzed in detail for the second-order generator models widely used in power system studies. A generic, practical method for validating generator synchronous inductance is proposed and proven with actual field measurements and model validation study results using the GENQEC model. The generator field current compensation factor of the GENQEC model improves the field current accuracy independently of magnetic saturation. Its advantages are demonstrated in model parameter validation using field measurement results from in-service salient-pole and round-rotor synchronous generators. The proposed method with the GENQEC dynamic model can be used to establish a baseline for accurately validating generator direct-axis parameters using stator-decrement test results. The innovative method of validating generator synchronous d-axis reactance proposed in this article can be a practical and reliable alternative to the test methods provided by IEEE standards.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Collection System Topology for Deep-Sea Offshore Wind Farms Considering
           Wind Characteristics

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      Authors: Yang Fu;Yang Liu;Ling-ling Huang;Feixiang Ying;Fangxing Li;
      Pages: 631 - 642
      Abstract: DC series-parallel collection system has recently been widely discussed for integrating deep-sea OWFs because it saves the offshore HVDC stations. However, comparing with traditional offshore electrical collection systems, there is a unique operational problem introducing by the DC series-parallel system that is the wind power curtailment caused by the wind power fluctuations. In this paper, a rigorous mathematical analysis of wind power curtailment is conducted, and an optimization model considering wind power curtailment for DC series-parallel collection systems is proposed. To address the particularities of the series-parallel collection system in graph theory, an improved parthenogenetic algorithm (PGA) is suggested to address the optimization problem. The proposed model and optimization algorithms are tested based on a deep-sea OWF with 56 wind turbines (WTs). The simulation results show that considering wind power curtailment during the DC series-parallel system planning helps to save the levelized cable cost of energy (LCCOE) in the long term, and putting the wiring direction of the series as perpendicular as possible to the prevailing wind direction of the OWF helps to increase the power generation of the OWF and reduce LCCOE.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Distributed-Diode-Rectifiers-Based Offshore Wind Power MVDC
           Direct-Transmission System

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      Authors: Mingyang Yang;Xu Cai;Aisikaer Wusiman;Jianwen Zhang;Jing Lyu;
      Pages: 643 - 653
      Abstract: An offshore wind power medium-voltage direct-current (MVDC) transmission system based on distributed diode rectifiers (DRs) is proposed to realize the DC transmission of offshore wind power and eliminate offshore platforms. A coordinated control strategy between wind turbines (WTs) is proposed to greatly reduce the transmission voltage ripple and current ripple for this system. A small-signal state-space model for the WT line-side converter control system is established. The less damped terms in the control system are found through system eigenvalues, and the stabilization control method is further proposed. A joint control strategy between the onshore converter station and offshore WTs is proposed to achieve system fault ride-through. This strategy can quickly transmit the onshore AC grid's fault information to each WT and consume unbalanced power by the dc choppers inside WTs. The simulation results in PSCAD verify the effectiveness of the proposed control strategy.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Experimental Low-Speed Performance Evaluation and Comparison of Sensorless
           Passive Algorithms for SPMSM

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      Authors: Alessandro Benevieri;Mario Marchesoni;Massimiliano Passalacqua;Luis Vaccaro;
      Pages: 654 - 664
      Abstract: Sensorless algorithms for PMSM have achieved an increasing interest in the technical literature. They can be divided into active methods and passive methods. Active methods exploit rotor anisotropy by injecting high voltage frequency signals, whereas passive methods are based on observers. Even if passive methods do not have the drawbacks of active methods – acoustic noise, torque ripple and harmonic distortion - their effectiveness is reduced in the low speed region. For this reason, active methods are usually used at low speed and the motor control switches to passive methods in the high-speed region. Since high frequency injection is associated to many drawbacks, the aim of passive methods is to work at lower speed as possible or, ideally, to be able to start directly the motor. That is particularly true for Surface-Mounted PMSM: since they have a low anisotropy, high frequency injection should be particularly elevate to achieve sufficient signal-to-noise ratio. It is difficult to compare the performance of passive algorithms proposed in the technical literature since experimental tests have been done with different conditions: motors, inverter features, measurements, type of tests, etc. In this paper, five different sensorless passive algorithms for Surface-Mounted PMSM, selected among the most promising algorithms available in the technical literature, are compared, performing the same tests on the same experimental setup, to achieve a fair comparison and establishing the most performing one.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Detection of Structural Magnet Defects for Permanent Magnet Synchronous
           Motors

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      Authors: Gurkan Kucukyildiz;Ersin Yolacan;Hasan Ocak;Metin Aydin;
      Pages: 665 - 674
      Abstract: This paper presents a novel method for the detection of magnet cracks or defects through back electromotive force (EMF) voltage, line current and vibration signals for radial flux permanent magnet (PM) synchronous motors. An integer slot PM motor with 12 poles is used in the study. Different types of faults including both radial and axial magnet crack defects with multiple magnet fault scenarios and multiple pole fault cases are studied in detail. In addition, the severity of magnet fault is also investigated. Random forest based magnet defect detection is utilized and a classification scheme is proposed in order to analyze the changes in the harmonics arising from single or multiple, radial or axial magnet defects. The results clearly show that the harmonics is altered in such a manner that it is possible to determine not only the magnet fault but the type of the magnet defect using motor voltage, current or vibration data.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • A Novel Flux Barrier Parametrization for Synchronous Reluctance Machines

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      Authors: Oğuz Korman;Mauro Di Nardo;Michele Degano;Chris Gerada;
      Pages: 675 - 684
      Abstract: This paper presents a novel parametrization for the flux barrier profiles of synchronous reluctance and permanent magnet assisted reluctance machines. In literature there are several methods used to design rotor flux barriers of various types, however the vast majority use only a few parameters to characterize their shape. These approaches are proven to be effective in terms of simplicity and computational burden required to achieve an optimal design. However, simplified parametrizations certainly decrease the degrees of freedom when designing the whole barrier shape. In this paper, an attempt to increase the degrees of freedom, introducing a novel rotor flux barrier parametrization, is presented. The method proposed uses natural splines, defined by the positions of a set of control points, to form the shape of the flux barriers. The spline and state-of-the-art barrier profiles are compared from both electromagnetic and mechanical perspectives. The results of this investigation show that by increasing the degrees of freedom it is possible to obtain better performance characteristics. The proposed parametrization is applied to a 6-pole synchronous reluctance motor and its permanent magnet assisted variant, optimized for a traction application. A prototype has been manufactured and tested to experimentally validate the design methodology.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Analysis of Excitation Winding Induced EMF in Non-Overlapped Stator Wound
           Field Synchronous Machines

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      Authors: Xiao-Yong Sun;Zi-Qiang Zhu;Lei Xu;
      Pages: 685 - 695
      Abstract: Different from the induced electromotive force (EMF) in armature winding, the induced EMF in excitation winding is detrimental to the performance of wound field synchronous machines by causing unstable excitation field and thus extra torque pulsation and losses. Moreover, it also imposes challenges to machine control, particularly for high-speed operation. This article investigates the induced EMF in the excitation winding of 3-phase non-overlapped stator wound field synchronous machines (SWFSMs). It has revealed that the amplitude of the excitation winding induced EMF is largely dependent on the slot-pole combination. Therefore, with suitable slot-pole combinations, the induced EMF issue will be significantly alleviated by eliminating low-order induced EMF harmonics. Although the excitation winding induced EMF can also be reduced by passive techniques, e.g., optimization and shaping of rotor pole arc, the average torque will be greatly degraded as well. Finally, the finite element predictions are validated by measurements on two prototyped non-overlapped SWFSMs.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Influence of Rotor Eccentricity On Electromagnetic Performance of
           2-pole/3-slot PM Motors

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      Authors: T. R. He;Z. Q. Zhu;F. Xu;Y. Wang;H. Bin;L. M. Gong;
      Pages: 696 - 706
      Abstract: This paper investigates the influence of static and dynamic rotor eccentricities on electromagnetic performance, including air-gap flux density, back electromotive force (EMF), electromagnetic torque, cogging torque, and unbalanced magnetic force (UMF), of a 2-pole/3-slot permanent magnet (PM) motor considering eccentricity ratio, eccentricity angle, and rotor initial angle. Both finite element analyses and experiments show that in a 2-pole/3-slot PM motor, the static rotor eccentricity leads to unbalanced magnitudes and phase angles of fundamental back-EMFs of three phases but does not change the harmonic contents, while the dynamic rotor eccentricity will not cause unbalance in three phase back-EMFs but affects the harmonic contents of back-EMFs and their phase angles, which causes asymmetric positive and negative half-periods and corresponding even harmonics of phase back-EMF waveform. In addition, both static and dynamic rotor eccentricities have negligible influence on the average torque, but result in large torque ripple, cogging torque, and UMF.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Improved MRAS Rotor Position Observer Based on Control Winding Power
           Factor for Stand-Alone Brushless Doubly-Fed Induction Generators

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      Authors: Mohamed G. Hussien;Yi Liu;Wei Xu;Abdul Khalique Junejo;Said M. Allam;
      Pages: 707 - 717
      Abstract: The main contribution of this study is to propose a new rotor position observer with the approach of model reference adaptive system (MRAS) associated with the quantity of control winding (CW) power factor of the brushless doubly-fed induction generator (BDFIG) for sensorless voltage control target in stand-alone systems. The proposed observer relies on the field-orientation scheme of power winding (PW) side. The proposed sensorless methodology does not need any computation process with integration for obtaining the flux components. In addition, the new methodology can reduce the voltage sensors required for detecting the actual CW voltage quantities to be used in the calculations process of the proposed MRAS procedure by directly realizing the CW reference stationary voltages from the input path of SVPWM. This would ensure the simplicity of the suggested procedure for detecting the rotational position of the generator. The stability confirmation of the presented estimation method is analyzed and realized with the aid of technique of hyperstability concept and aided with the criteria of Popov's analysis. Moreover, the verification of robustness for the proposed observer is studied via uncertainty issues of machine parameters. Comprehensive simulation and experimental results are carried out on a test prototype of BDFIG to verify the control procedure.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • $infty$ +State-of-Charge+Observer+and+Probabilistic+Lifetime+Prediction+of+Lithium-Ion+Batteries&rft.title=IEEE+Transactions+on+Energy+Conversion&rft.issn=0885-8969&rft.date=2022&rft.volume=37&rft.spage=718&rft.epage=728&rft.aulast=Wei;&rft.aufirst=Guangzhong&rft.au=Guangzhong+Dong;Yan+Xu;Zhongbao+Wei;">A Hierarchical Approach for Finite-Time H- $infty$ State-of-Charge
           Observer and Probabilistic Lifetime Prediction of Lithium-Ion Batteries

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      Authors: Guangzhong Dong;Yan Xu;Zhongbao Wei;
      Pages: 718 - 728
      Abstract: Accurate state-of-charge (SOC) estimation and lifetime prognosis of lithium-ion batteries are of great significance for reliable operations of energy storage systems. This paper proposes a novel two-layer hierarchical approach for online SOC estimation and remaining-useful-life (RUL) prediction based on a robust observer and Gaussian-process-regression (GPR). At the bottom layer, an equivalent-circuit model is first developed to describe battery dynamics. Second, a combination method of a recursive least square method and a finite time H-$infty$ observer is designed to estimate battery open-circuit-voltage (OCV) and SOC through stability and robustness analysis. Next, the estimated OCV and SOC are fed into the top layer to generate the incremental-capacity-analysis-based aging feature, through which a robust signature associated with battery aging is identified. The feature is further employed for RUL prediction based on GPR. The salient advantages of the proposed approach are that it can provide robust parameter estimation in a given finite-time interval, and the GPR-based RUL prediction can tackle long-term uncertainties in a principled Bayesian manner. Theoretical analysis and experimental results demonstrate the effectiveness of the proposed SOC observer and lifetime prediction methods.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • New Adaptive Starting Scalar Control Scheme for Induction Motor Variable
           Speed Drives

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      Authors: Juan Carlos Travieso-Torres;Camilo Contreras-Jara;Matias Diaz;Norelys Aguila-Camacho;Manuel A. Duarte-Mermoud;
      Pages: 729 - 736
      Abstract: This article proposes a new scalar control scheme for variable speed drives of induction motors with an adaptive starting control. Besides centrifugal pumps, blowers, and fans, it expands the scalar control application field to move, for instance, a class of conveyor belts with nominal torque loading. An adaptive passivity-based controller designed for a class of nonlinear systems encompassing the dynamical machine model keeps a constant stator starting current. The proposed methodology uses information from the motor nameplate. Hence, it keeps a simple control scheme, not needing parameter estimates, neither adjusting controllers nor variable observers depending on them. Experimental results with a 10 HP downscaled laboratory prototype validate the proposed control strategy effectiveness. It shows rated-starting torque capabilities and fast speed response. Moreover, it shows lower stator current consumption than previous scalar control schemes.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Two-Level Surrogate-Assisted Transient Parameters Design Optimization of a
           Wound-Field Synchronous Machine

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      Authors: Y. Ma;J. Wang;Y. Xiao;L. Zhou;Z. Q. Zhu;
      Pages: 737 - 747
      Abstract: The rapid development of ultra-high voltage direct current transmission systems has placed greater demands on the design optimization of transient parameters for large wound-field synchronous machines (WFSMs) in power systems, such as large synchronous condenser for dynamic reactive power compensation. This paper proposes a novel two-level surrogate-assisted multi-objective optimization method for WFSMs that can optimize transient parameters including per-unit reactance and time constants rapidly and accurately. To facilitate the manufacture of a prototype for verification, the proposed method is applied to the optimization of a WFSM for scale-down generator application. This method is employed to deal with the excessive number of design parameters, issues of multi-objective evaluation and strong coupling between objectives that either result in inaccuracy or become time-consuming by using conventional methods. To generate the training set for the surrogate model efficiently by finite element analysis, an improved arbitrary rotor position standstill time response (SSTR) method is employed to identify all transient parameters simultaneously in a single test, while Latin hypercube design is used to capture data features. The optimal WFSM designed by using the proposed method is prototyped and measured. It confirms that the proposed method can achieve high validity and high optimization efficiency simultaneously.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Optimization of Electrolyte Rebalancing in Vanadium Redox Flow Batteries

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      Authors: Mehdi Jafari;Apurba Sakti;Audun Botterud;
      Pages: 748 - 751
      Abstract: This paper presents a novel algorithm to optimize energy capacity restoration of vanadium redox flow batteries (VRFBs). VRFB technologies can have their lives prolonged through a partial restoration of the lost capacity by electrolyte rebalancing. Our algorithm finds the optimal “number” and “time” of these rebalancing services to minimize the life-time service cost, while maximizing revenues from energy arbitrage. We show that the linearized form of this problem can be analytically solved, and that the objective function is convex. To solve the complete problem, we develop a two-step mixed integer linear programming (MILP) algorithm, which first finds the bounds for optimal number of services and then optimizes the number, and time of the services. We then present a theoretical analysis and optimization results for a case study of energy arbitrage in New York ISO.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
  • Introducing the IEEE PES Resource Center

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      Pages: 752 - 752
      Abstract: Presents information on the IEEE PES Resource Center.
      PubDate: March 2022
      Issue No: Vol. 37, No. 1 (2022)
       
 
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