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  Subjects -> ELECTRONICS (Total: 193 journals)
Showing 1 - 200 of 277 Journals sorted alphabetically
Acta Electronica Malaysia     Open Access  
Advanced Materials Technologies     Hybrid Journal  
Advances in Electrical and Electronic Engineering     Open Access   (Followers: 7)
Advances in Electronics     Open Access   (Followers: 94)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 8)
Advances in Power Electronics     Open Access   (Followers: 39)
Advancing Microelectronics     Hybrid Journal  
Aerospace and Electronic Systems, IEEE Transactions on     Hybrid Journal   (Followers: 353)
American Journal of Electrical and Electronic Engineering     Open Access   (Followers: 26)
Annals of Telecommunications     Hybrid Journal   (Followers: 9)
APSIPA Transactions on Signal and Information Processing     Open Access   (Followers: 9)
Archives of Electrical Engineering     Open Access   (Followers: 14)
Australian Journal of Electrical and Electronics Engineering     Hybrid Journal  
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 8)
Batteries     Open Access   (Followers: 7)
Batteries & Supercaps     Hybrid Journal  
Bell Labs Technical Journal     Hybrid Journal   (Followers: 30)
Bioelectronics in Medicine     Hybrid Journal  
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 22)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 38)
Biomedical Instrumentation & Technology     Hybrid Journal   (Followers: 6)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 13)
BULLETIN of National Technical University of Ukraine. Series RADIOTECHNIQUE. RADIOAPPARATUS BUILDING     Open Access   (Followers: 1)
Bulletin of the Polish Academy of Sciences : Technical Sciences     Open Access   (Followers: 1)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 47)
China Communications     Full-text available via subscription   (Followers: 9)
Chinese Journal of Electronics     Hybrid Journal  
Circuits and Systems     Open Access   (Followers: 15)
Consumer Electronics Times     Open Access   (Followers: 5)
Control Systems     Hybrid Journal   (Followers: 308)
ECTI Transactions on Computer and Information Technology (ECTI-CIT)     Open Access  
ECTI Transactions on Electrical Engineering, Electronics, and Communications     Open Access   (Followers: 1)
Edu Elektrika Journal     Open Access   (Followers: 1)
Electrica     Open Access  
Electronic Design     Partially Free   (Followers: 123)
Electronic Markets     Hybrid Journal   (Followers: 7)
Electronic Materials Letters     Hybrid Journal   (Followers: 4)
Electronics     Open Access   (Followers: 104)
Electronics and Communications in Japan     Hybrid Journal   (Followers: 10)
Electronics For You     Partially Free   (Followers: 103)
Electronics Letters     Hybrid Journal   (Followers: 26)
Elkha : Jurnal Teknik Elektro     Open Access  
Embedded Systems Letters, IEEE     Hybrid Journal   (Followers: 55)
Energy Harvesting and Systems     Hybrid Journal   (Followers: 4)
Energy Storage     Hybrid Journal  
Energy Storage Materials     Full-text available via subscription   (Followers: 3)
EPE Journal : European Power Electronics and Drives     Hybrid Journal  
EPJ Quantum Technology     Open Access   (Followers: 1)
EURASIP Journal on Embedded Systems     Open Access   (Followers: 11)
Facta Universitatis, Series : Electronics and Energetics     Open Access  
Foundations and Trends® in Communications and Information Theory     Full-text available via subscription   (Followers: 6)
Foundations and Trends® in Signal Processing     Full-text available via subscription   (Followers: 10)
Frequenz     Hybrid Journal   (Followers: 1)
Frontiers of Optoelectronics     Hybrid Journal   (Followers: 1)
Geoscience and Remote Sensing, IEEE Transactions on     Hybrid Journal   (Followers: 209)
Haptics, IEEE Transactions on     Hybrid Journal   (Followers: 4)
IACR Transactions on Symmetric Cryptology     Open Access  
IEEE Antennas and Propagation Magazine     Hybrid Journal   (Followers: 100)
IEEE Antennas and Wireless Propagation Letters     Hybrid Journal   (Followers: 81)
IEEE Journal of Emerging and Selected Topics in Power Electronics     Hybrid Journal   (Followers: 51)
IEEE Journal of the Electron Devices Society     Open Access   (Followers: 9)
IEEE Journal on Exploratory Solid-State Computational Devices and Circuits     Hybrid Journal   (Followers: 1)
IEEE Power Electronics Magazine     Full-text available via subscription   (Followers: 75)
IEEE Transactions on Antennas and Propagation     Full-text available via subscription   (Followers: 73)
IEEE Transactions on Automatic Control     Hybrid Journal   (Followers: 58)
IEEE Transactions on Circuits and Systems for Video Technology     Hybrid Journal   (Followers: 26)
IEEE Transactions on Consumer Electronics     Hybrid Journal   (Followers: 44)
IEEE Transactions on Electron Devices     Hybrid Journal   (Followers: 19)
IEEE Transactions on Information Theory     Hybrid Journal   (Followers: 26)
IEEE Transactions on Power Electronics     Hybrid Journal   (Followers: 78)
IEEE Transactions on Signal and Information Processing over Networks     Full-text available via subscription   (Followers: 12)
IEICE - Transactions on Electronics     Full-text available via subscription   (Followers: 12)
IEICE - Transactions on Information and Systems     Full-text available via subscription   (Followers: 5)
IET Cyber-Physical Systems : Theory & Applications     Open Access   (Followers: 1)
IET Energy Systems Integration     Open Access  
IET Microwaves, Antennas & Propagation     Hybrid Journal   (Followers: 35)
IET Nanodielectrics     Open Access  
IET Power Electronics     Hybrid Journal   (Followers: 57)
IET Smart Grid     Open Access  
IET Wireless Sensor Systems     Hybrid Journal   (Followers: 18)
IETE Journal of Education     Open Access   (Followers: 4)
IETE Journal of Research     Open Access   (Followers: 11)
IETE Technical Review     Open Access   (Followers: 13)
IJEIS (Indonesian Journal of Electronics and Instrumentation Systems)     Open Access   (Followers: 3)
Industrial Electronics, IEEE Transactions on     Hybrid Journal   (Followers: 74)
Industrial Technology Research Journal Phranakhon Rajabhat University     Open Access  
Industry Applications, IEEE Transactions on     Hybrid Journal   (Followers: 38)
Informatik-Spektrum     Hybrid Journal   (Followers: 2)
Instabilities in Silicon Devices     Full-text available via subscription   (Followers: 1)
Intelligent Transportation Systems Magazine, IEEE     Full-text available via subscription   (Followers: 13)
International Journal of Advanced Research in Computer Science and Electronics Engineering     Open Access   (Followers: 18)
International Journal of Advances in Telecommunications, Electrotechnics, Signals and Systems     Open Access   (Followers: 11)
International Journal of Antennas and Propagation     Open Access   (Followers: 11)
International Journal of Applied Electronics in Physics & Robotics     Open Access   (Followers: 4)
International Journal of Computational Vision and Robotics     Hybrid Journal   (Followers: 5)
International Journal of Control     Hybrid Journal   (Followers: 11)
International Journal of Electronics     Hybrid Journal   (Followers: 7)
International Journal of Electronics and Telecommunications     Open Access   (Followers: 13)
International Journal of Granular Computing, Rough Sets and Intelligent Systems     Hybrid Journal   (Followers: 3)
International Journal of High Speed Electronics and Systems     Hybrid Journal  
International Journal of Hybrid Intelligence     Hybrid Journal  
International Journal of Image, Graphics and Signal Processing     Open Access   (Followers: 16)
International Journal of Microwave and Wireless Technologies     Hybrid Journal   (Followers: 10)
International Journal of Nanoscience     Hybrid Journal   (Followers: 1)
International Journal of Numerical Modelling: Electronic Networks, Devices and Fields     Hybrid Journal   (Followers: 4)
International Journal of Power Electronics     Hybrid Journal   (Followers: 25)
International Journal of Review in Electronics & Communication Engineering     Open Access   (Followers: 4)
International Journal of Sensors, Wireless Communications and Control     Hybrid Journal   (Followers: 10)
International Journal of Systems, Control and Communications     Hybrid Journal   (Followers: 4)
International Journal of Wireless and Microwave Technologies     Open Access   (Followers: 6)
International Transaction of Electrical and Computer Engineers System     Open Access   (Followers: 2)
JAREE (Journal on Advanced Research in Electrical Engineering)     Open Access  
Journal of Biosensors & Bioelectronics     Open Access   (Followers: 4)
Journal of Advanced Dielectrics     Open Access   (Followers: 1)
Journal of Artificial Intelligence     Open Access   (Followers: 11)
Journal of Circuits, Systems, and Computers     Hybrid Journal   (Followers: 4)
Journal of Computational Intelligence and Electronic Systems     Full-text available via subscription   (Followers: 1)
Journal of Electrical and Electronics Engineering Research     Open Access   (Followers: 35)
Journal of Electrical Bioimpedance     Open Access  
Journal of Electrical Bioimpedance     Open Access   (Followers: 2)
Journal of Electrical Engineering & Electronic Technology     Hybrid Journal   (Followers: 7)
Journal of Electrical, Electronics and Informatics     Open Access  
Journal of Electromagnetic Analysis and Applications     Open Access   (Followers: 8)
Journal of Electromagnetic Waves and Applications     Hybrid Journal   (Followers: 9)
Journal of Electronic Design Technology     Full-text available via subscription   (Followers: 6)
Journal of Electronics (China)     Hybrid Journal   (Followers: 5)
Journal of Energy Storage     Full-text available via subscription   (Followers: 4)
Journal of Engineered Fibers and Fabrics     Open Access   (Followers: 2)
Journal of Field Robotics     Hybrid Journal   (Followers: 3)
Journal of Guidance, Control, and Dynamics     Hybrid Journal   (Followers: 184)
Journal of Information and Telecommunication     Open Access   (Followers: 1)
Journal of Intelligent Procedures in Electrical Technology     Open Access   (Followers: 3)
Journal of Low Power Electronics     Full-text available via subscription   (Followers: 10)
Journal of Low Power Electronics and Applications     Open Access   (Followers: 10)
Journal of Microelectronics and Electronic Packaging     Hybrid Journal  
Journal of Microwave Power and Electromagnetic Energy     Hybrid Journal   (Followers: 3)
Journal of Microwaves, Optoelectronics and Electromagnetic Applications     Open Access   (Followers: 11)
Journal of Nuclear Cardiology     Hybrid Journal  
Journal of Optoelectronics Engineering     Open Access   (Followers: 4)
Journal of Physics B: Atomic, Molecular and Optical Physics     Hybrid Journal   (Followers: 30)
Journal of Power Electronics & Power Systems     Full-text available via subscription   (Followers: 11)
Journal of Semiconductors     Full-text available via subscription   (Followers: 5)
Journal of Sensors     Open Access   (Followers: 26)
Journal of Signal and Information Processing     Open Access   (Followers: 9)
Jurnal ELTIKOM : Jurnal Teknik Elektro, Teknologi Informasi dan Komputer     Open Access  
Jurnal Rekayasa Elektrika     Open Access  
Jurnal Teknik Elektro     Open Access  
Jurnal Teknologi Elektro     Open Access  
Kinetik : Game Technology, Information System, Computer Network, Computing, Electronics, and Control     Open Access  
Learning Technologies, IEEE Transactions on     Hybrid Journal   (Followers: 12)
Magnetics Letters, IEEE     Hybrid Journal   (Followers: 7)
Majalah Ilmiah Teknologi Elektro : Journal of Electrical Technology     Open Access   (Followers: 2)
Metrology and Measurement Systems     Open Access   (Followers: 6)
Microelectronics and Solid State Electronics     Open Access   (Followers: 28)
Nanotechnology Magazine, IEEE     Full-text available via subscription   (Followers: 42)
Nanotechnology, Science and Applications     Open Access   (Followers: 6)
Nature Electronics     Hybrid Journal   (Followers: 1)
Networks: an International Journal     Hybrid Journal   (Followers: 5)
Open Electrical & Electronic Engineering Journal     Open Access  
Open Journal of Antennas and Propagation     Open Access   (Followers: 9)
Optical Communications and Networking, IEEE/OSA Journal of     Full-text available via subscription   (Followers: 15)
Paladyn. Journal of Behavioral Robotics     Open Access   (Followers: 1)
Power Electronics and Drives     Open Access   (Followers: 2)
Problemy Peredachi Informatsii     Full-text available via subscription  
Progress in Quantum Electronics     Full-text available via subscription   (Followers: 7)
Pulse     Full-text available via subscription   (Followers: 5)
Radiophysics and Quantum Electronics     Hybrid Journal   (Followers: 2)
Recent Advances in Communications and Networking Technology     Hybrid Journal   (Followers: 3)
Recent Advances in Electrical & Electronic Engineering     Hybrid Journal   (Followers: 9)
Research & Reviews : Journal of Embedded System & Applications     Full-text available via subscription   (Followers: 5)
Revue Méditerranéenne des Télécommunications     Open Access  
Security and Communication Networks     Hybrid Journal   (Followers: 2)
Selected Topics in Applied Earth Observations and Remote Sensing, IEEE Journal of     Hybrid Journal   (Followers: 56)
Semiconductors and Semimetals     Full-text available via subscription   (Followers: 1)
Sensing and Imaging : An International Journal     Hybrid Journal   (Followers: 2)
Services Computing, IEEE Transactions on     Hybrid Journal   (Followers: 4)
Software Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 78)
Solid State Electronics Letters     Open Access  
Solid-State Circuits Magazine, IEEE     Hybrid Journal   (Followers: 13)
Solid-State Electronics     Hybrid Journal   (Followers: 9)
Superconductor Science and Technology     Hybrid Journal   (Followers: 3)
Synthesis Lectures on Power Electronics     Full-text available via subscription   (Followers: 3)
Technical Report Electronics and Computer Engineering     Open Access  
TELE     Open Access  
Telematique     Open Access  
TELKOMNIKA (Telecommunication, Computing, Electronics and Control)     Open Access   (Followers: 9)
Transactions on Electrical and Electronic Materials     Hybrid Journal  
Universal Journal of Electrical and Electronic Engineering     Open Access   (Followers: 6)
Ural Radio Engineering Journal     Open Access  
Visión Electrónica : algo más que un estado sólido     Open Access   (Followers: 1)
Wireless and Mobile Technologies     Open Access   (Followers: 6)
Wireless Power Transfer     Full-text available via subscription   (Followers: 4)
Women in Engineering Magazine, IEEE     Full-text available via subscription   (Followers: 11)
Електротехніка і Електромеханіка     Open Access  

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Similar Journals
Journal Cover
Industry Applications, IEEE Transactions on
Journal Prestige (SJR): 1.02
Citation Impact (citeScore): 4
Number of Followers: 38  
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0093-9994
Published by IEEE Homepage  [191 journals]
  • IEEE Industry Applications Society
    • Abstract: Provides a listing of current staff, committee members and society officers.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • IEEE Transactions On Industry Applications
    • Abstract: Advertisement, IEEE.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Information for authors
    • Abstract: Provides instructions and guidelines to prospective authors who wish to submit manuscripts.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Time Horizon-Based Model Predictive Volt/VAR Optimization for Smart Grid
           Enabled CVR in the Presence of Electric Vehicle Charging Loads
    • Authors: Shailendra Singh;Vijay Babu Pamshetti;S. P. Singh;
      Pages: 5502 - 5513
      Abstract: This paper investigates the need of coordinated operation of conservation voltage reduction (CVR) in the presence of electric vehicle (EV) penetration in the active distribution network. In order to analyze the impact of both the technologies (CVR and EV), a time horizon-based model predictive Volt/VAR optimization (VVO) methodology has been introduced in smart grid framework. The proposed VVO methodology operates in centralized as well as local controls under different time scale of operation, including cloud transient effects on solar photovoltaic (PV) power output. Moreover, the control algorithms also consider the uncertainties in load demand and PV power generation. The VVO methodology has been validated with and without presence of EV loads in the distribution network. The VVO includes the impact of different EV charging loads having the ability of participation in reactive power support at selected charging points. This is also referred to as vehicle-to-grid operation in terms of reactive power dispatch only. Besides, the voltage and VAR regulation through smart inverters of PVs and EV charging station has been fruitfully utilized in global as well as local domain. A real-time Volt/VAR droop based controller has been introduced to control the smart inverters reactive power dispatch. To validate the developed methodology, a real-time cosimulation framework, using real-time digital simulator and Python interface, has been built. The proposed model predictive VVO algorithm has been tested and validated on a modified IEEE 34 bus test system. The simulated results reveal that significant CVR energy savings and losses reduction has been achieved without violating the system constraints. The voltage control algorithm works well in both slow and fast time scales.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • A Dynamic Weighted Aggregation Equivalent Modeling Approach for the DFIG
           Wind Farm Considering the Weibull Distribution for Fault Analysis
    • Authors: Yuhao Zhou;Long Zhao;Igor B. M. Matsuo;Wei-Jen Lee;
      Pages: 5514 - 5523
      Abstract: The developing process of the aggregated dynamic equivalent model (DEM) for doubly-fed induction generator (DFIG) wind farms could be less computational and more efficient compared with the multimachine DEM, but less accurate when wind speed differences exist inside the wind farm. In addition, the wind speed differences contribute to the different activation patterns of the crowbar systems of DFIGs. Therefore, a dynamic weighted aggregation modeling approach is proposed in this paper to improve the applicability of the aggregated DEM for DFIG wind farm. First, the Gaussian density distance clustering algorithm is applied to segment the wind speed power curve into different zones such that each segmented zone is corresponded to one equivalent aggregated machine. Then the dynamic weighted aggregation equivalent model could be developed based on the conventional aggregated DEM, where the weighting factors for each generator are calculated according to the Weibull distribution of wind speeds. Different scenarios are simulated in MATLAB/Simulink environment to analyze the applicability of the proposed dynamic weighting equivalent model. The simulation results show the effectiveness of the proposed method.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Coordinated Control of PEV and PV-Based Storages in Residential Systems
           Under Generation and Load Uncertainties
    • Authors: Faeza Hafiz;Anderson Rodrigo de Queiroz;Iqbal Husain;
      Pages: 5524 - 5532
      Abstract: Energy storage deployment in residential and commercial applications is an attractive proposition for ensuring proper utilization of solar photovoltaic (PV) power generation. Energy storage can be controlled and coordinated with PV generation to satisfy electricity demand and minimize electricity purchases from the grid. For optimal energy management, PV generation and load demand uncertainties need to be considered when designing a control method for the PV-based storage system. Another resource available at the residential level is the plug-in electric vehicle (PEV) which also has bi-directional power flow capability. The charging and discharging routines of the PEV can be controlled to help reduce the energy drawn from the power grid during peak hours. In this paper, a method of coordinated optimal control between PV-based storage and PEV storage is proposed considering the stochastic nature of solar PV generation and load demand. The stochastic dual dynamic programming algorithm is employed to optimize the charge/discharge profiles of PV-based storage and PEV storage to minimize the daily household electricity purchase cost from the grid. Simulation analysis shows the advantage of the coordinated control compared to other control strategies.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • UPS Node-Based Workload Management for Data Centers Considering Flexible
           Service Requirements
    • Authors: Fang Cao;Yajing Wang;Feng Zhu;Yujie Cao;Zhaohao Ding;
      Pages: 5533 - 5542
      Abstract: As the IT sector is rapidly growing all over the world, more and more energy is consumed by data centers, which leads to the continuous increase of operating costs. Among other factors, the load management among uninterruptible power supply (UPS) nodes should be considered in the energy management model of the data center since its energy efficiency is correlated with the load ratio. In this article, an energy management scheme of the data center, which focuses on the workload scheduling among UPS nodes, is proposed to improve its operation efficiency. The flexible service requirement of batch workloads is also modeled in the proposed scheme to illustrate the cost of flexibility. In the proposed scheme, the efficiency of the UPS node is modeled as a function of the load ratio. Meanwhile, the cost of inconvenience is introduced to represent the flexible service requirements of batch workloads. A stochastic formulation is established to address the uncertainties involved in the scheduling process. Simulated case studies are provided, and the results demonstrate the effectiveness of the proposed approach.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Optimal Sizing of Shipboard Carbon Capture System for Maritime Greenhouse
           Emission Control
    • Authors: Sidun Fang;Yan Xu;Zhengmao Li;Zhaohao Ding;Lu Liu;Hongdong Wang;
      Pages: 5543 - 5553
      Abstract: Under increasingly stringent emission regulations, carbon capture system (CCS) is a feasible alternative to reduce the shipping greenhouse gas (GHG) emission before the maturity of renewable energy technology. In this sense, this article proposes an optimal sizing method to determine the capacity of shipboard CCS under strict energy efficiency operating index (EEOI) constraint. The proposed model is formulated as a two-stage planning problem, where the first stage is to determine the capacity of CCS and the expanded capacity of energy storage system to sustain the operation of CCS, and the second stage is a joint shipboard generation and demand-side management model to address the power shortage issue led by the CCS integration. Extensive simulations demonstrate that under EEOI constraint, the CCS integration is feasible to reduce the shipping GHG emission, and the proposed joint generation and demand-side management method is able to relieve the power shortage issue of shipboard CCS. The corresponding average carbon capture level increases 11.9% with the joint management.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Flexible Demand Resource Pricing Scheme: A Stochastic Benefit-Sharing
    • Authors: Zhaohao Ding;Feng Zhu;Yajing Wang;Ying Lu;Lizi Zhang;
      Pages: 5554 - 5563
      Abstract: With the rapidly increased penetration of renewable generations, the incentive-based demand-side management (DSM) shows great value in alleviating the uncertainty and providing flexibility for a microgrid. However, how to price those demand resources becomes one of the most significant challenges for promoting the incentive-based DSM under microgrid environments. In this article, a flexible demand resource pricing scheme is proposed. Instead of using the utility function of end-users like most existing literature, the economic benefit of the flexible demand resources is evaluated by the operation performance enhancement of the microgrid, and correspondingly, the resource is priced based on a benefit-sharing approach. An iteration-based chance-constrained method is established to calculate the economic benefit and shared compensation for the demand resource providers. Meanwhile, the financial risks for the microgrid operator due to uncertain factors are mitigated by the chance-constrained criterion. The proposed scheme is examined by an experimental microgrid to illustrate its effectiveness.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Day-Ahead Market Optimal Bidding Strategy and Quantitative Compensation
           Mechanism Design for Load Aggregator Engaging Demand Response
    • Authors: Fei Wang;Xinxin Ge;Kangping Li;Zengqiang Mi;
      Pages: 5564 - 5573
      Abstract: In a typical electricity market, the load aggregator (LA) bids in the wholesale market to purchase electricity and meet the expected demand of its customers in the retail market. However, considering the uncertainty of the wholesale market prices, the LA has to undertake all the risks arising from the price volatility in the wholesale market, which may make the LA suffer from financial loss under some scenarios such as price spikes. To this end, first, this article proposes an optimal bidding strategy model for the LA that implements the demand response program (DRP), which enables the LA to reduce the risk of financial loss caused by price volatility. The bidding model is a mixed integer linear programming problem, which can be solved efficiently via a commercial solver. Second, making a rational and quantitative compensation mechanism is significant for the LA to induce its customers to participate in the DRP while there are few studies investigating it, hence, this article designs a quantitative compensation mechanism for the LA. Case studies using a dataset from the Thames valley vision verify the effectiveness of the proposed bidding model. The results confirm that the implementation of DRP not only brings great profits to LA but also benefits the other entities in the electricity market.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Assessing the Impact of Harmonics and Interharmonics of Top and Mudpump
           Variable Frequency Drives in Drilling Rigs
    • Authors: Alexandre B. Nassif;
      Pages: 5574 - 5583
      Abstract: Declining extraction costs and process efficiencies have incented the revival of the oil and gas sector postrecession. The application of drilling rigs has been done more efficiently. These loads are very large, temporary in nature, and mobile. The drilling of each well can be done as quickly as a few hours and typically not more than a few days. These massive loads are complex to own, maintain, and operate, as a result few specialized drillers share the market. Because of the requirements for variable speed and control, drilling rigs are driven by variable frequency drives (VFDs), which are in their clear majority of older technologies such as six-pulse thyristor bridge or SCR-driven motors. These technologies are known to impose steep ramp rates (up and down) as well as rich harmonic content and variable, typically low, power factor. Furthermore, the locations of drilling rigs are typically remote, where distribution systems, if present, are weak, which lead to large background voltage distortions when such loads are present. This paper presents measurements, simulations, and analytical assessments of the characteristics and effects of harmonics and interharmonics (IHs) generated by top-drive and mud-pump VFDs in a large drilling rig operated in Alberta, Canada. Measurement results reveal very high harmonic and IH generation. To further refine the impact assessment of these harmonic emissions, the harmonic attenuation effect of the VFDs is quantified to avoid overestimating the harmonic generation of the loads. The thermal impact of the current harmonics on the coupling transformer is also quantified.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Grid-Connected Wind Power Plants: A Survey on the Integration Requirements
           in Modern Grid Codes
    • Authors: Yuan-Kang Wu;Shih-Ming Chang;Paras Mandal;
      Pages: 5584 - 5593
      Abstract: In recent years, the integration of wind power generation facilities, and especially offshore wind power generation facilities, into power grids has increased rapidly. Therefore, the grid codes concerning wind power integration have become a major factor in ensuring power system reliability. This work compares grid codes about wind power integration around the world. The grid codes of Denmark, Ireland, the U.K., Germany, Spain, China, the U.S., Canada, and other countries are considered. The most important of these grid codes concern reactive power, frequency regulation, fault ride through, and power quality. Several grid codes also address communication, ramp rate, and offshore wind power plants. This work provides information on the future of grid code requirements for offshore wind power integration, which helps the system operators ensure the safe operation of a power system with a high penetration of wind power generation.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Power Grid Optimal Topology Control Considering Correlations of System
    • Authors: Mohannad Alhazmi;Payman Dehghanian;Shiyuan Wang;Bhavesh Shinde;
      Pages: 5594 - 5604
      Abstract: This article presents a probabilistic formulation and solution technique for the application of dc optimal power flow-based network topology control through transmission line switching strategies. Efficient utilization of the point estimation method (PEM) is pursued to model the system uncertainties, i.e., the stochastic load profile and the intermittent renewable generation. In order to address the computational effectiveness of the suggested probabilistic methodology, the PEM formulation is harnessed by a scenario reduction approach to capture the correlations of the system uncertainties, thereby achieving a more robust and faster operation solution for day-ahead and real-time applications. The proposed approach is applied to a modified IEEE 118-bus test system, where it demonstrates its attractive performance under different test scenarios. To further verify the efficiency and scalability of the proposed algorithms on large-scale systems, the proposed analytics are applied to 200-bus synthetic grid of central Illinois. AC feasibility and transient stability checks are performed on both test systems and the results are extensively analyzed.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • The Equipment Grounding System as an Effective Bonding Topology for
           Telecommunications Environments
    • Authors: Ken Michaels;
      Pages: 5605 - 5612
      Abstract: Bseing provided an adequate telecommunications bonding infrastructure is one of the primary concerns for telecommunications cabling designers and installers for new and existing installations. Although not considered a safety ground where ground-fault current is concerned, the telecommunications bonding infrastructure has importance where the components are intended to equalize potentials in the event of lightning, electrostatic discharge, electromagnetic interference, and other transient events that may be imposed on it, or within telecommunications spaces. Very recently, several telecommunications design groups with varying responsibilities for data center, military encryption, and commercial facilities have explored feasible options in providing an equipotential plane for their telecommunications bonding infrastructure, especially in locations where exposed metal frame of the building is not available; the most prominent of these options being the use of the ac equipment grounding conductor system due to the abundance of metallic surface area utilized for the ac premises wiring system. This article is intended to present field-testing data and draw technical conclusions from the same so as to verify whether the equipment grounding system is viable as an alternative bonding infrastructure plane that can achieve the same effect as the standard practices in place today.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • On Electrical Safety in Academic Laboratories
    • Authors: Rodolfo Araneo;Payman Dehghanian;Massimo Mitolo;
      Pages: 5613 - 5620
      Abstract: Academic laboratories should be a safe environment in which one can teach, learn, and conduct research. Sharing a common principle, the prevention of potential accidents and imminent injuries is a fundamental goal in the laboratory environments. In addition, academic laboratories are attributed exceptional responsibility to instill in students the culture of the safety, the basis of risk assessment, and of the exemplification of the prudent practices around energized objects. Undergraduate laboratory assignments may normally be framed based upon the repetition of established experiments and procedures, whereas academic research laboratories may involve new methodologies and/or apparatus, for which the hazards may not be completely known to the faculty and student researchers. Yet, the academic laboratory should be an environment free of electrical hazards for both routine experiments and research endeavors, and faculty should offer practical inputs and safety-driven insights to academic administration to achieve such a paramount objective. In this article, the authors discuss the challenges to electrical safety in modern academic laboratories, where users may be exposed to harmful touch voltages.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Solar Power Ramp Event Forewarning With Limited Historical Observations
    • Authors: Wenli Zhu;Li Zhang;Ming Yang;Bo Wang;
      Pages: 5621 - 5630
      Abstract: Timely and accurate forewarning of solar power ramp events (SPREs) is crucial for a power system operation. In this article, a novel forewarning method for SPREs is proposed based on credal network (CN) and imprecise Dirichlet model (IDM). A new expression of SPRE is proposed, which focuses on the power change caused by meteorological fluctuation. Considering that the single-valued probability may not provide convincing results in case of insufficient ramp event records, probability interval is adopted to reflect the ambiguous correlation between SPREs and meteorological conditions. The meteorological evidences are mapped to ramp events by a CN to enhance the sensitivity of SPRE identification. The structure of the CN is established by the learning algorithm with respect to the relations between SPRE and meteorological conditions, as well as different meteorological conditions. Furthermore, an extended IDM is developed to estimate the interval-valued parameters in the CN. Then, a credal classifier is established to output the ramp forewarning result. The effectiveness of the proposed method is verified through case studies, and obvious improvement on the accuracy of ramp forewarning can be seen.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Cyber-Physical Design and Implementation of Distributed Event-Triggered
           Secondary Control in Islanded Microgrids
    • Authors: Yu Wang;Tung Lam Nguyen;Yan Xu;Zhengmao Li;Quoc-Tuan Tran;Raphael Caire;
      Pages: 5631 - 5642
      Abstract: A microgrid (MG) is a cyber-physical system with coupled power and communication networks. The centralized secondary control of MGs with periodical communications restricts system efficiency and resilience. This article proposes a distributed event-triggered secondary control scheme in islanded MGs with its cyber-physical implementation. The proposed control scheme operates with the reduced frequency of communications depending on the MG states change “events” (e.g., load variations and communication failures). Besides, the secondary control objectives, including frequency/voltage regulation and accurate real/reactive power sharing, are decoupled into two timescales. Instead of designing event-triggering conditions (ETCs) for each secondary control functions, only ETCs for power sharing control in slower timescale are designed. Thus, the communication burden is significantly reduced since communications among neighbor controllers are only needed at the event-triggered time. The proposed controller has been tested on a hardware-in-the-loop (HIL) platform, where the physical system is modeled in the OPAL-RT and the cyber system is realized in Raspberry Pis. The control effectiveness is validated by the HIL results.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Analysis of Historical Transformer Failure and Maintenance Data: Effects
           of Era, Age, and Maintenance on Component Failure Rates
    • Authors: Andrew D. Stringer;Christopher C. Thompson;Carolina I. Barriga;
      Pages: 5643 - 5651
      Abstract: For several decades, The U.S. Army Corps of Engineers has maintained a unique database of equipment failure and maintenance data for critical facilities. This article takes a closer look at historical transformer failure and maintenance data, and provides a unique analysis of failure trends. Detailed analysis shows that failure rates for different categories of transformers demonstrate unique trends over time, with equipment age, and with respect to preventative maintenance levels. By analyzing over 144 thousand unit years of operational data, this article paints a more complete picture of component reliability. The data show that careful consideration of detailed failure and maintenance can better upgrade facility design and maintenance decisions, ultimately leading to improved system reliability and reduced operational costs.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Field Verification of Autonomous Anti-Islanding Schemes and Grid Support
           Functions of an Inverter-Based Microturbine Distributed Generator
    • Authors: Alexandre B. Nassif;Ricardo Torquato;
      Pages: 5652 - 5658
      Abstract: Canada-wide climate change plans have been put in place in the form of legislation and emission reduction programs. As part of these measures, reduced amounts of natural gas can be vented, incinerated, or flared. These programs have a direct impact on the Canadian oil and gas industry. Other measures mandate the decommissioning of high-emission thermal power plants, such as coal-fired generation. At the same time, governments are encouraging the wide-scale adoption of distributed energy resources (DERs). Because of these changes, natural gas fired DERs have been proliferating in oilfields to consume the byproduct natural gas and most major oil and gas companies are diversifying their portfolio to include generation assets. It is a more sustainable and environmentally friendly scenario as compared to the previous status quo. From an electric utility standpoint, this represents a change in paradigm, because distribution systems are traditionally planned to be radial and only experience power flowing from the substation to the load centers. This change requires utilities to adapt to new concerns and requirements, which span from operation to health and safety hazards. Among these, anti-islanding is likely the most important concern to allow the safe and reliable operation of a distribution system. The standard method to avoid unintended islanded operation is the direct transfer trip. Under exceptional circumstances, the utility may waive this requirement if an alternative acceptable method is in use. This article addresses existing anti-islanding schemes and covers in detail an alternative anti-islanding method native to many inverters. This article contains the philosophy of such method and measurement results captured during commissioning of a DER containing the scheme. Furthermore, this article highlights the evolution of inverter-based generator technologies and how the revision of applicable standards (IEEE 1547) can improve the reliable operation of such DERs.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Topology of Continuous Availability for LED Lighting Systems
    • Authors: Giuseppe Parise;Marco Allegri;Luigi Parise;Raffaele Pennacchia;Fabrizio Regoli;Giorgio Vasselli;
      Pages: 5659 - 5665
      Abstract: Lighting systems with a big number of luminaires in large halls are a case of distributed loads that need topologies with modularity, whenever possible to ensure a uniform distribution of the supplying circuits, an easier installation, management, and maintenance. The light emitting diode (LED) luminaires give a great impact on the system operation due to their auxiliary series devices and to the high inrush currents of the ac-dc switching power supplies. This article proposes a topology to design LED lighting systems, configured in a modular scheme of a main ac distribution and a branch dc distribution supplying luminaires clusters. Each cluster is provided as a “double-dual corded” equipment with double power supply and double control type, digital, and analogic. The suggested topology aims to make available a system that allows overcoming fault situations by design and permits maintenance activities limiting and recovering degradation conditions. In this way, the lighting system of special locations, for which there is the willingness-to-accept greater financial costs against loss service risks, can satisfy the requirement of continuous availability system. To provide more details on the proposed design criteria this article describes, as case study, the lighting system of a parliamentary hall with one thousands of luminaires.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Design of an Industrial IoT-Based Monitoring System for Power Substations
    • Authors: Long Zhao;Igor Brandao Machado Matsuo;Yuhao Zhou;Wei-Jen Lee;
      Pages: 5666 - 5674
      Abstract: The Internet of Things (IoT) concept allows objects to share data through wired or wireless connections for communication purposes. The industrial Internet of Things (IIoT) is an extended concept of IoT that refers to an integration of data acquisition, communication, and processing on a real-time network. Currently, IIoT has been involved with the development of smart grids in many applications. As the operation of power systems is extremely time-critical, low-latency communication needs to be considered for most control and monitoring applications. Real-time capability of IoT is considered as a key feature for monitoring and control applications of power systems. Therefore, system operators can use the real-time monitoring system to provide better decisions for both technical- and financial-related matters. In this article, a high-speed IIoT-based monitoring system with recording functions is developed and implemented for a power system substation. Due to the high reliability and processing speed of field-programmable gate arrays (FPGAs), an FPGA-embedded controller is adopted in this system. The IoT platform also provides remote visualization for system operators in real-time. This article mainly aims to provide a practical application that was implemented and tested in a real-power substation. The system incorporates the features of an IoT platform with the needs of high-speed real-time applications while using a single high-resolution time source as the reference for both steady-state and transient conditions.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Investigation of Ferroresonance Causing Sustained High Voltage at a
           De-Energized 138 kV Bus: A Case Study
    • Authors: Yunfei Wang;Xiaodong Liang;Iraj Rahimi Pordanjani;Ryan Cui;Ali Jafari;Colin Clark;
      Pages: 5675 - 5686
      Abstract: Ferroresonance causes overvoltage and excessive current flow on potential transformers (PT), which can cause substantial damage to PTs and interrupt the power system normal operation. In this article, a sustained overvoltage event on a de-energized 138 kV bus after the circuit breakers were opened to clear a phase A to ground fault at a Canadian transmission utility power grid is investigated. The power systems computer aided design (PSCAD) simulation model is created and validated using the field measurement data. The PSCAD simulation results indicate that the ferroresonance due to a limb-type open-core magnetic PT interacting with the grading capacitors of circuit breakers is the root cause of the problem. Due to the linearized magnetizing characteristic, the limb-type open-core PT is generally believed to be immune from ferroresonance; however, the event and simulation in this article demonstrate that the ferroresonance can still occur using this type of PT. The mitigation methods for the ferroresonance in this system are proposed; case and sensitivity studies using these methods are conducted to validate their effectiveness. In this article, the criterion on how to properly size a damping resistor or a damping reactor at the PT secondary is proposed, and the performance comparison using a damping resistor or a damping reactor for this system is demonstrated through case and sensitivity studies.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Behavior of Protective Relays During Subsynchronous Resonance in
           Transmission Line and Adaptation of Generator Out-of-Step Protection
    • Authors: Salman Rezaei;
      Pages: 5687 - 5698
      Abstract: Subsynchronous resonance (SSR) is a phenomenon in which electrical energy is exchanged between the generator and the transmission system below power frequency. SSR occurs due to the interaction of a series-compensated transmission line with a generator. It results in shaft oscillation and out-of-step (OOS) condition. During SSR, the magnitude of voltage and current is increased. It also increases probable occurrence of ferroresonance. It is obviously clear that protective relays are affected in such conditions. In this article, Manitoba Hydro electrical network is examined with series capacitors by PSCAD/EMTDC to investigate the impact of SSR on the operation of different types of protective relays. SSR is mostly concerned with transmission lines. In addition, swing characteristic of impedance during SSR causes activation of the OOS blocking (OSB) element of distance relay and OOS protection of generator. Hence, an adaptive algorithm based on subharmonic measurement and ferroresonance analysis in the time domain is proposed for OOS characteristic of generator protective relay to recognize SSR condition and make a decision on behavior of the function. Finally, the algorithm is examined in SSR condition to certify the correct operation.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Relationship Between Historical Trends, Equipment Age, Maintenance, and
           Circuit Breaker Failure Rates
    • Authors: Christopher C. Thompson;Carolina I. Barriga;
      Pages: 5699 - 5707
      Abstract: Circuit breakers are ubiquitous devices that vigilantly protect personnel, equipment, and critical functions. But circuit breakers fail-and how they fail matters. The U.S. Army Corps of Engineers collected and analyzed a database of equipment records over several decades. This article studies the details of that database to provide new insight to failure trends, showing that failure rates have varied historically, that failure rates change as a function of equipment age, and that failure rates respond to preventative maintenance activity, often counterintuitively. New figures show unpublished details that improve understanding and reveal limitations of previous circuit breaker statistics. These data challenge persistent assumptions of reliability-centered maintenance and reliability design.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Solid-State Transformers for Distribution Systems–Part II:
           Deployment Challenges
    • Authors: Saleh A. Saleh;Emre Ozkop;Basim Alsayid;Chistian Richard;Xavier Francis St. Onge;Katie M. McDonald;Liuchen Chang;
      Pages: 5708 - 5716
      Abstract: Solid-state transformers (SSTs) have diverse designs and constructions that make them suitable for various industrial applications, including distributions systems. This new breed of transformers has been developed to support the typical functionalities of core-type distribution transformers, along with new functionalities, such as controlling power flows, integrating dc distribution systems, utilizing distributed generation and storage units, supporting load-side voltage/frequency control, and improving the power quality. As SSTs become candidates for distribution systems, their deployment can pose challenges for distribution systems. Such challenges include the cost, protection, size and weight, efficiency, and adequate grounding designs. This article discusses some of the challenges that face the deployment of SSTs in distribution systems. In addition, this article provides a comparison between core-type and SST transformers for applications in distribution systems. The comparison between the transformers is made in terms of their efficiency, cost, and weight. Finally, this article makes several recommendations for future works that can further facilitate the deployment of SSTs in distribution systems.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • A Test-Bed for Researching the Interactions of Underexcitation and
           Overexcitation Limiters of Synchronous Generators with Protection
    • Authors: Aurélio L. M. Coelho;Paulo M. Silveira;Francisco R. A. C. Baracho;
      Pages: 5717 - 5726
      Abstract: A test-bed implemented in a real-time digital simulation environment is presented in this article to perform coordination studies between protection functions and excitation limiters of automatic voltage regulators of synchronous generators. A hardware-in-the-loop simulation is implemented in laboratory to test and evaluate several protection schemes during underexcited and overexcited events. The interactions among the underexcitation and overexcitation limiters (UEL and OEL) with these protection functions are investigated, and the best settings for their coordination are proposed. This article increases the scope of [1] and [2] by including the interactions among the protection functions ANSI 24 (V/Hz), ANSI 59 (overvoltage), and ANSI 81 (underfrequency and overfrequency) with the OEL, and the interactions among the protection functions ANSI 21 (distance) and ANSI 27 (undervoltage) with the UEL in addition to the coordination between the protection function ANSI 40 (loss of excitation) and the UEL. Thus, the appropriate settings for these protection and controls are proposed for the excitation system developed. The main results are presented and discussed.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Genetic Algorithm-Based Optimization of Overcurrent Relay Coordination for
           Improved Protection of DFIG Operated Wind Farms
    • Authors: Nima Rezaei;Mohammad Nasir Uddin;Ifte Khairul Amin;Mohammad Lutfi Othman;Marayati Marsadek;
      Pages: 5727 - 5736
      Abstract: Rigorous protection of wind power plants is a critical aspect of the electrical power protection engineering. A proper protection scheme must be planned thoroughly while designing the wind plants to provide safeguarding for the power components in case of fault occurrence. One of the conventional protection apparatus is overcurrent relay (OCR), which is responsible for protecting power systems from impending faults. However, the operation time of OCRs is relatively long and accurate coordination between these relays is convoluted. Moreover, when a fault occurs in wind farm-based power system, several OCRs operate instead of a designated relay to that particular fault location, which could result in unnecessary power loss and disconnection of healthy feeders out of the plant. Therefore, this article proposes a novel genetic algorithm (GA)-based optimization technique for proper coordination of the OCRs in order to provide improved protection of the wind farms. The GA optimization technique has several advantages over other intelligent algorithms, such as high accuracy, fast response, and most importantly, it is capable of achieving optimal solutions considering nonlinear characteristics of OCRs. In this article, the improvement in protection of wind farm is achieved through optimizing the relay settings, reducing their operation time, time setting multiplier of each relay, improving the coordination between relays after implementation of IEC 60255-151:2009 standard. The developed algorithm is tested in simulation for a wind farm model under various fault conditions at random buses and the results are compared with the conventional nonlinear optimization method. It is found that the new approach achieves significant improvement in the operation of OCRs for the wind farm and drastically reduces the accumulative operation time of the relays.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Dual-Slot Power-Pickup Structure for Contactless Strip Inductive Power
           Track System
    • Authors: Jia-You Lee;I-Lin Chen;Chien-Tzu Ko;
      Pages: 5737 - 5746
      Abstract: In this paper, a dual-slot power pickup suitable for an inductive power track system was developed using contactless power transmission techniques. A new strip-type inductive power track with high magnetic flux density and magnetic field uniformity is proposed. A dual-slot type power-pickup structure with high magnetic flux linkage was designed using equivalent magnetic circuit model analysis to improve the power transmission capacity and transmitting efficiency. To verify the contactless transmission characteristics of the proposed strip-type inductive power track system, a 1.2 m long laboratory-scale inductive power track was constructed. The SPLSC topology was used as the compound resonant circuit of a full-bridge inverter. According to the experimental results, the maximum transmitting efficiency of overall system is 72.52% at an output power of 289.52 W.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Optimal Number of Flux Modulation Pole in Vernier Permanent Magnet
           Synchronous Machines
    • Authors: Huayang Li;Z. Q. Zhu;Yue Liu;
      Pages: 5747 - 5757
      Abstract: This paper aims to identify the optimal number of flux modulation pole (FMP) in Vernier permanent magnet synchronous machines (VPMSMs) with concentrated tooth-coil windings. First, the influence of number of FMP on machine performance is revealed based on the unified permanent magnet magnetomotive force permeance analytical model. It is found that for a fixed stator slot number, there always exists an optimal number of FMP to maximize the torque, thanks to the enhanced contribution by the fundamental permeance harmonic. Then, the influence of critical dimensional parameters, including the machine diameter, the permanent magnet thickness, and the width of FMP, on the electromagnetic performance of VPMSMs with different numbers of FMP are parametrically analyzed by both analytical and finite element analyses. Results show that the VPMSMs with the optimal number of FMP always have advantages of a higher torque density together with a reduced PM volume, particularly for those with a relatively large diameter. Finally, two VPMSM prototypes with different numbers of FMP are manufactured and tested to validate the analyses.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Analytical Analysis and Performance Characterization of Brushless Doubly
           Fed Machines With Multibarrier Rotors
    • Authors: Peng Han;Julia Zhang;Ming Cheng;
      Pages: 5758 - 5767
      Abstract: The brushless doubly fed reluctance machine (BDFRM) with a multibarrier rotor has shown great promise in applications where high reliability and low maintenance cost are required, such as offshore wind turbines. This paper presents a systematic analytical analysis and performance characterization of the BDFRM with a multibarrier rotor. First, the airgap magnetomotive force distributions under both open circuit and loaded condition are detailed, based on which a more practical rule than the widely accepted p1 - p2 ≠1 is derived to effectively avoid the unbalanced magnetic pull in such machines. Analytical formulas different from those for slip-ring doubly fed induction machines are then obtained to estimate inductance parameters for circuit modeling and control purposes. Design equations for initial sizing and torque density comparison are also developed, with achievable torque density discussed. Both finite-element analysis and experimental tests are conducted to validate the effectiveness of the presented analysis.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Vold–Kalman Filtering Order Tracking Based Rotor Demagnetization
           Detection in PMSM
    • Authors: Min Zhu;Bin Yang;Wensong Hu;Guodong Feng;Narayan C. Kar;
      Pages: 5768 - 5778
      Abstract: Rotor magnet condition is important to maintain a stable permanent magnet synchronous motor (PMSM) operation. In this paper, Vold-Kalman filtering order tracking (VKF-OT) and dynamic Bayesian network (DBN) are employed for the real-time rotor demagnetization detection from the torque ripple. First, a torque ripple model of the PMSM considering electromagnetic noise is proposed, and the torque variation is studied to determine the effect of the demagnetization on the torque ripple, which indicates that it is feasible to detect the magnet demagnetization by analyzing the torque ripple. Then the torque is processed by wavelet transform to eliminate the electromagnetic disturbances. Second, the VKF-OT is introduced to track the order of the torque ripple of the PMSM to extract the torque ripple characteristics as the feature reflecting changes in magnet status. Third, the feature is employed to train the DBN for the rotor magnet demagnetization detection and prediction during motor operation. The proposed approach is a noninvasive and an online method that can be embedded in the physical motor controller. The validation results demonstrate that this method can detect the uniform demagnetization over a wide motor speed range.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • A Novel Thermographic Method and Its Improvement to Evaluate Defects in
           Laminated and Soft Magnetic Composites Devices
    • Authors: Luca Ferraris;Fausto Franchini;Emir Pošković;
      Pages: 5779 - 5788
      Abstract: Electromagnetic devices may be affected by the presence of local losses due to material defects or magnetic anomalies caused by mechanical processing. The localization of such defects is the main goal of this article; a noninvasive method has been pursued to perform the inspection and detection of imperfections or defects. The adopted approach is based on the observation of the device under test with a high-speed IR camera; no limitations in size and shapes devices are considered and the method can be widely adopted. Examples of defects detection in the magnetic circuit realization are proposed, both for traditional ferromagnetic laminated sheets and for soft magnetic composites.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Slotless Lightweight Motor for Aerial Applications
    • Authors: Md Sariful Islam;Rajib Mikail;Iqbal Husain;
      Pages: 5789 - 5799
      Abstract: A slotless, lightweight permanent-magnet (PM) motor with high pole count is designed and analyzed for a drone system that requires four motors of 0.5 kW each for a 2-kW propulsion power to attain the required torque-speed profile. The design optimization was carried out using finite-element analysis that lead to a slotless stator with outer rotor Halbach PM configuration achieving high power density, zero cogging torque, low torque ripple, sinusoidal back electromotive force, and good system efficiency. The Halbach configuration is found to have superior power density and torque ripple over the conventional concepts for the aerial applications. The power density and efficiency of the slotless motor can be enhanced through the use of nonconventional thermoplastic material and Halbach segmentation. The resulting low inductance of the slotless machine introduces a controls challenge, but it can be overcome with today's enabling technology of wide bandgap devices. A comprehensive analysis and comparison of the slotless design with an equivalent slotted-radial version showed the superiority of the former. An optimum slotless design has been prototyped and test results along with analysis are presented.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • High-Speed PM Generators for Organic Rankine Cycle Systems: Reduction of
           Eddy Current Rotor Losses
    • Authors: Grazia Berardi;Nicola Bianchi;
      Pages: 5800 - 5808
      Abstract: In an organic Rankine Cycle system, the permanent magnet (PM) generator is directly coupled to high-speed turbine shaft, to increase system efficiency avoiding the gearbox introduction. Current time harmonics induce high-frequency currents in rotor parts, which cause temperature increase. PMs are strongly affected by the operating temperature, since both remanence and coercive force decrease. This article shows that rotor losses of a high-speed PM generator strongly depend on both winding arrangement and power electronic conversion system connected to the generator itself. Several analyses are carried out to compare different solutions.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Modeling and Investigation of Self-Excited Reluctance Generators for Wind
    • Authors: Yawei Wang;Nicola Bianchi;
      Pages: 5809 - 5817
      Abstract: In the last few years, wind energy conversion systems have been increasingly installed worldwide. The self-excited reluctance generators (SERGs) are found to be potential candidates as isolated wind turbine generators, especially for low- and medium-power applications. This article focuses on the characteristics of SERG for wind turbine generation system. A simplified dynamic model of the generation system is developed, discretized by backward Euler formula, and simulated. With this model, the process of self-excitation and operation characteristic of SERG are investigated. Considering the varying generated voltage at different speeds, variable capacitances allow suitable regulation of the voltage. The variation of capacitance with speed is obtained by the active and reactive power (PQ) balances method. Combining the power speed characteristics of wind turbine and SERG, the PQ balances method is also used to determine the “optimal capacitor and resistor combination” that achieves the highest usage of wind power. This article exhibits the performance of SERG for wind applications, and most importantly, makes the prediction of the highest energy conversion efficiency of the system.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Modeling and Verification of Electrical Stress in Inverter-Driven Electric
           Machine Windings
    • Authors: Yanyan Xie;Julia Zhang;Franco Leonardi;Alfredo R. Munoz;Michael W. Degner;Feng Liang;
      Pages: 5818 - 5829
      Abstract: This article develops a high-fidelity physics-based modeling approach to predict the voltage stress and current distributions in individual conductors of electric machine windings driven by pulsewidth modulation (PWM) voltages. This is the first step to better understand how PWM voltages stress the winding insulation of inverter-driven electric machines. The high-fidelity finite element (FE) models of electric machine windings in this article account for frequency-dependent winding parasitic parameters, and are capable of investigating the impact of wire positions on the winding parasitic parameters, hence the voltage stress and current distributions of individual conductors. A stator core with manually wound windings was built to verify the fidelity of the FE model. First, simulations and tests were conducted to obtain the voltage stress and current distributions in individual conductors in a simple form-wound coil, then a simple random-wound coil with a reduced number of conductors. Then, the model was extended to a complicated winding structure, including multiple coils, turns, and parallel strands. Tests were conducted to obtain the voltage and current of each conductor for this complicated winding. The measured and simulated results show good consistency. The effects of wire positions on voltage stress and current distributions were also investigated in both simulations and tests.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Design Optimization and Performance Investigation of Novel Linear
           Induction Motors With Two Kinds of Secondaries
    • Authors: Qinfen Lu;Longxiang Li;Jiawen Zhan;Xiaoyan Huang;Jiongjiong Cai;
      Pages: 5830 - 5842
      Abstract: In order to reduce the transverse edge effect of a single-sided linear induction motors (SLIMs) for a low-speed Maglev train, this article proposes novel SLIMs with symmetry/asymmetry double-slit secondary. First, the end effects of the conventional SLIMs with flat-solid and cap-solid secondaries are investigated based on three-dimensional (3-D) finite-element model. For the latter one, the influences of slip frequency and secondary structure parameters are obtained as well. Second, the structures of the proposed double-slit secondaries are introduced, and the topology parameters are investigated by a single-variable optimization method. Third, the force performances of SLIMs with proposed two kinds of double-slit secondaries are compared with those of the SLIMs with the traditional cap-solid secondary. Finally, a prototype of SLIM with asymmetry double-slit secondary is manufactured and tested to validate the predictions. The results show that the SLIM with the proposed asymmetry double-slit secondary can improve the force performances due to reduction in the transverse end effect.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Improved Duty-Ratio-Based Direct Torque Control for Dual Three-Phase
           Permanent Magnet Synchronous Machine Drives
    • Authors: Yuan Ren;Z. Q. Zhu;James E. Green;Yun Li;Shiwu Zhu;Zijian Li;
      Pages: 5843 - 5853
      Abstract: This article investigates the duty-ratio-based direct torque control strategies for dual three-phase permanent magnet synchronous machine (PMSM) drives. The classical switching-table-based direct torque control (ST-DTC) for the dual three-phase drives usually suffers from significant harmonic currents and a large torque ripple. To reduce the harmonic currents, 12 combined voltage vectors are generated and employed as active vectors. Then, the duty-ratio-based ST-DTC is introduced to reduce the torque ripple. Considering that the typical duty-ratio-based ST-DTC exhibits the drawbacks of machine parameter dependent and a certain degree of failure rate in the duty ratio regulation, a simple and effective method taking into account the effect of the machine speed is employed to obtain the duty ratio. Afterward, to prevent the issue of the inverter thermal imbalance caused by using only one type of zero vectors, two types of zero vectors are employed in the switching sequences. With the proposed method, not only the harmonic currents have been suppressed, but also the torque ripple can be considerably reduced, while the merits of the classical ST-DTC such as simple structure and excellent dynamic performance are preserved. The experimental results validate the effectiveness of the proposed strategy.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Analysis and Reduction of Cogging Torque for Flux-Switching Permanent
           Magnet Machines
    • Authors: Xiaofeng Zhu;Wei Hua;Gan Zhang;
      Pages: 5854 - 5864
      Abstract: In this article, a new modeling approach is proposed to investigate cogging torque and the corresponding reduction techniques of flux-switching permanent magnet (FSPM) machines. First, based on the superposition of each single rotor tooth, an analytical expression of cogging torque in FSPM machines is derived and confirmed by the finite-element analysis (FEA). Then, three feasible techniques, i.e., successively shifting rotor teeth, alternately shifting rotor teeth, and stepped skewing rotor blocks, are proposed for cogging torque minimization of FSPM machines. Correspondingly, generally analytical expressions of these three methods are deduced, through which the analytically optimal shifting angles can be determined. Besides, the cogging torque harmonics are analyzed by both analytical expressions and FEA, and then, the multidimensional techniques, namely three rotor-based reduction methods combined with the optimal stator tooth width, are introduced and studied to further suppress cogging torque. Finally, prototyped machines are manufactured and tested, and the corresponding experiments verify the effectiveness of the reduction methods.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Impact of Geometry on the Rotor Iron Losses in Synchronous Reluctance
    • Authors: Emanuel Castagnaro;Giacomo Bacco;Nicola Bianchi;
      Pages: 5865 - 5872
      Abstract: A parametric analysis is carried out to investigate the dependence of the rotor iron losses on the stator and rotor geometry of several synchronous reluctance machines. Six four-pole rotors have been designed with different flux barriers per pole through a multiobjective differential evolution algorithm coupled to a finite-element analysis (FEA). Two different stators with 24 and 36 slots are considered. During the optimizations, a rapid finite-element evaluation has been used to predict the performance of the motors. After that, an accurate time stepping FEA is used for computation of the rotor iron losses. Finally, the interaction between the rotor iron losses and several rotor and stator geometrical parameters is highlighted. The effect of the current time harmonics have also been taken into account, weighting its impact on the rotor losses.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Two-Converter-Based Frequency-Sharing Operation and Control of a Brushless
           Doubly Fed Reluctance Motor Drive
    • Authors: Ronald S. Rebeiro;Andrew M. Knight;
      Pages: 5873 - 5880
      Abstract: This article investigates a novel two-converter-based operation of a brushless doubly fed reluctance machine (BDFRM). The BDFRM has a ducted rotor, and the stator is wound with two distributed windings, which are fed from two separate power converters. Operation theory with frequency sharing between the two windings is introduced. The prototype BDFRM design, machine assembly, and the corresponding motor drive implementation processes are discussed. The control strategy for frequency sharing mode of operation with two variable winding frequencies is discussed. Subsequently, the BDFRM drive is tested in frequency sharing mode at varying speed levels and loads.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Study on the Axial Leakage Magnetic Flux in a Spoke Type Permanent Magnet
           Synchronous Motor
    • Authors: Sung Gu Lee;Jaenam Bae;Won-Ho Kim;
      Pages: 5881 - 5887
      Abstract: A spoke type permanent magnet synchronous motor generates axial leakage magnetic flux due to its flux-concentrating rotor structure, and therefore degrades the motor performance. Although a three-dimensional finite element method (3-D FEM) can be used to estimate the axial leakage magnetic flux, it requires a significant amount of time for analysis. In this article, a calibration coefficient is proposed to estimate the axial leakage magnetic flux using the two-dimensional finite element method (2-D FEM) instead of 3-D FEM. This calibration coefficient is expressed in terms of the major geometric parameters of a motor and can be calculated using the material information of the permanent magnet and the bridge of the rotor core in 2-D FEM. The validity of the proposed equation is verified through 3-D FEM and other tests.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Analysis and Reduction of Circulating Current Loss of Armature Wires in
           Permanent Magnet Synchronous Machines
    • Authors: Katsumi Yamazaki;Takahiro Furuhashi;Haiyan Yui;Hideki Ohguchi;Satoshi Imamori;Masao Shuto;
      Pages: 5888 - 5896
      Abstract: In this article, we investigate the loss reduction of permanent magnet machines, whose armature windings consist of parallel wires. First, the impact of the loss caused by the circulating currents in the parallel armature wires is estimated by finite-element analysis. The calculated total electrical loss is compared with the experimental result of a prototype motor. The measured and calculated results are found to be in good agreement. In addition, it is revealed that the circulating armature current loss is larger than the usual copper loss, which is estimated only by the total armature current and the armature winding resistance. Next, the loss reduction by reducing the number of parallel wires is discussed. The optimal number of parallel wires is found by considering the tradeoff between the reduction of circulating current loss and increases in the other losses, such as usual copper loss and core loss.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Local Degradation in Soft Magnetic Materials: A Simplified Modeling
    • Authors: Marco Cossale;Martin Kitzberger;Gereon Goldbeck;Gerd Bramerdorfer;Dietmar Andessner;Wolfgang Amrhein;
      Pages: 5897 - 5905
      Abstract: Manufacturing processes, such as cutting, welding, or assembling originate mechanical and thermal effects that locally introduce residual stresses. Consequently, the magnetic material shows a decrease of magnetic permeability and an increase of hysteresis losses. The adoption of catalogue data for electrical machines simulation thus follows low accuracy of the results. This article deals with effective modeling of the degradation of relative permeability and iron losses in soft magnetic materials due to manufacturing processes. The degradation profile is assessed by means of experimental activity conducted on a set of ring samples where the damaged material has been removed through electrical discharge machining. The proposed modeling approach is particularly relevant when it is implemented in numerical simulation tools.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • On-Line Detection of Stator Faults in DTC-Driven IM Using SC Impedance
           Matrix Off-Diagonal Term
    • Authors: Alberto Berzoy;Hassan H. Eldeeb;Osama A. Mohammed;
      Pages: 5906 - 5915
      Abstract: Stator's turn fault is one of the major causes of induction motor's (IM) failures. IMs are typically driven by direct torque control (DTC) on industry applications and more recently, on electric vehicles. In this article, an in-service nonintrusive stator turn fault detection (FD) technique for a DTC inverter fed IM is proposed. The presented FD strategy is based on the on-line estimation of the off-diagonal term in the IM sequence components (SCs) impedance matrix. The FD does not require prior knowledge of IM's parameters, and it is robust and immune against sensor's inherent errors. Furthermore, the proposed FD routine is able to detect incipient failure of approximately 1% fault severity factor. Two practical methodologies are applied for the computation of the SC: Symmetrical components and Savitzky-Golay filter. Simulation reinforced by experimental results demonstrated the success of the FD in a closed-loop controlled inverter driven IM.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Development of a Test Rig to Automate Efficiency Testing of Converter-Fed
           Induction Motors
    • Authors: John Mushenya;Mohamed Azeem Khan;Paul S. Barendse;
      Pages: 5916 - 5924
      Abstract: The increasing use of induction motors (IMs) with variable frequency drives for industrial process control and automation has necessitated the need to evaluate their energy efficiency in the presence of voltage and current harmonics. As the determination of IM efficiency is becoming mandatory in many countries, there is a need to develop a testing approach that eliminates inaccuracies due to the operator. This paper presents an automated efficiency testing procedure developed to mitigate the adverse effect of varying technical skill and competence levels of testing personnel on efficiency test results. This is a particularly useful development considering the recently proposed IEC/TS 60034-2-3 methodology which specifies identical tests between sinusoidal supply and converter operation. A comparison of several manual and automated efficiency tests on a 55-kW IM highlighted improvements in repeatability, correlation, and temperature variation due to the latter. In addition, the advanced data acquisition and computation capability of the measurement device used in the developed test rig provides an excellent platform to investigate the dynamic operation of IM drives.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Diagnosis of Open-Switch and Current Sensor Faults in PMSM Drives Through
           Stator Current Analysis
    • Authors: Sejir Khojet El Khil;Imed Jlassi;Antonio J. Marques Cardoso;Jorge O. Estima;Najiba Mrabet-Bellaaj;
      Pages: 5925 - 5937
      Abstract: Fault detection and fault accommodation, as well as fault tolerance, are important issues in closed-loop controlled three-phase converters. For such systems, power semiconductors and sensors are the most affected components by the occurrence of failures. Therefore, fault diagnosis and remedial operating strategies involving such components are highly required. In this paper, a new reliable approach is proposed, which aims to diagnose current sensor faults and power semiconductor open-circuit faults in permanent magnet synchronous motor drives. The proposed fault diagnosis scheme uses only the measured currents, which makes it suitable for real-time implementation. The performance of the proposed technique is analyzed through experiments.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Performances of a Fractional-Slot Concentrated-Winding Permanent Magnet
           Synchronous Machine Under Position Sensorless Control in Deep
           Flux-Weakening Region
    • Authors: Sithumini Ekanayake;Rukmi Dutta;M. F. Rahman;Minh Xuan Bui;
      Pages: 5938 - 5946
      Abstract: In recent time, the use of fractional-slot concentrated-winding (FSCW) stator has made it possible to drive the interior permanent magnet synchronous motors in very deep flux-weakening speed range. Many of such motors can operate along the maximum torque per voltage (MTPV) trajectory during the deep flux-weakening operation. Performances of the FSCW interior permanent magnet synchronous machine (IPMSM) while operating along the MTPV trajectory in the deep flux-weakening region under sensorless direct torque and flux control are yet to be investigated thoroughly. A 14-pole/18-slot FSCW IPMSM, which has a flux-weakening speed range of 9:1, was investigated in this paper. The position and speed were estimated using a sliding mode observer. Experimental results showed that satisfactory dynamic operation was possible during deep flux weakening only when a voltage compensation technique was integrated. This paper attempts to investigate the underlying reasons behind the requirement of the additional voltage compensation during deep flux weakening in the FSCW IPMSM.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Two-Stage Protection Circuit for a Multichanneled Power Electronic
           Converter Fed Large Asynchronous Hydrogenerating Unit
    • Authors: Raja R. Semwal;Raghu Selvaraj;Karthik Desingu;Thanga Raj Chelliah;Anto Joseph;
      Pages: 5947 - 5959
      Abstract: Reliable operation of multichannel power electronic converters in a large pumped storage power plant (PSPP) is a main concern among policymakers and/or hydropower project developers. This paper aims to design a two-stage protection circuit operation strategy for a large-rated doubly fed induction machine (DFIM) employed for variable-speed PSPPs. This paper initially studies the dynamic behavior of DFIM under symmetrical short-circuit faults in both the 400-kV power system and at stator terminal of the generating unit. Based on the fault analysis, a two-stage protection circuit (dc-link braking chopper circuit and crowbar protection circuit) operation strategy is designed in consideration of practical limitations. The designed operation strategy ensures the continuous operation of large-rated DFIM under marginal grid disturbances. To investigate the effective operation of a two-stage protection circuit, a 250-MW DFIM with multichannel power converters is implemented in MATLAB/Simulink tool. An experimental test is carried in a 2.2-kW DFIM laboratory prototype.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • PLL-Based Sliding Mode Observer Estimators for Sensorless Control of
           Rotor-Tied DFIG Systems
    • Authors: Mwana Wa Kalaga Mbukani;Nkosinathi Gule;
      Pages: 5960 - 5970
      Abstract: In this paper, a slip speed/position estimator for sensorless control of rotor-tied doubly-fed induction generator (DFIG) systems is presented. The proposed slip speed/position estimator is based on the association of the phase locked loop and the sliding mode observer. The proposed sliding mode observer uses the three-phase stator currents and the back electromotive force as state variables. This allows for the estimation of the slip speed/position before the rotor-tied DFIG is connected to the grid or to a load. The proposed phase locked loop helps in tracking the slip speed/position. The performance of the proposed slip speed/position estimation for sensorless operations are validated through experiments using a 5.5-kW custom-designed rotor-tied DFIG in grid-connected mode.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • A Megawatt-Scale Medium-Voltage High-Efficiency High Power Density
           “SiC+Si” Hybrid Three-Level ANPC Inverter for Aircraft Hybrid-Electric
           Propulsion Systems
    • Authors: Di Zhang;Jiangbiao He;Di Pan;
      Pages: 5971 - 5980
      Abstract: A hybrid-electric propulsion system is an enabling technology to make the aircraft more fuel saving, quieter, and lower carbide emission. In this article, a megawatt (MW) scale power inverter based on a three-level active neutral-point-clamped (3L-ANPC) topology will be developed. To achieve high efficiency, the switching devices operating at carrier frequency in the power converter are configured by the emerging silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors, while the conventional silicon (Si) insulated-gate bipolar transistors are selected for switches operating at the fundamental output frequency. To obtain high power density, dc bus voltage is increased from the conventional 270 V to medium voltage of 2.4 kV to reduce cable weight. Also, unlike the traditional 400 Hz dominated aircraft ac systems, the rated fundamental output frequency here is boosted to 1.4 kHz to drive the high-speed motor, which helps further to reduce the motor weight. Main hardware development and control modulation strategies are presented. Experimental results are presented to verify the performance of this MW-scale medium-voltage “SiC+Si” hybrid 3L-ANPC inverter. It is shown that the 1-MW 3L-ANPC inverter can achieve a high efficiency of 99% and a high power density of 12 kVA/kg.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Sensorless Robust Speed Controller Design of Pancake Axial Field PMDC
    • Authors: Arun Kumar Paul;
      Pages: 5981 - 5989
      Abstract: Due to superior multi-dimensional features (e.g., large torque to inertia ratio, fast response, high power density, negligible maintenance requirement, etc.) the axial-field pancake permanent magnet dc (PMDC) motors are popularly used for many control applications. When driven by pulsewidth modulation (PWM) controllers, due to their negligible electrical time constant, the armature current tends to be discontinuous. When the current disappears the measured armature voltage [i.e., back electromotive force (EMF)] is linearly related to its speed. In this article, the armature voltage at zero current is sampled to be used as feedback for speed control of axial field PMDC motors for wide range applications. Negligible prospect of demagnetization makes these motors ideal candidate to be controlled sensorless. When PWM frequency is large the armature time-constant poses as constraint for the back EMF to be available for sampling. The choice of PWM frequency is an important design parameter for the proposed concept. Further, this article explores, in practical domain, the usability of different control functions for robust speed control of pancake PMDC motors. It also details product design for sensorless PMDC motor speed controller using modified second-order sliding mode control function.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • On-Line Compensation of Resolver Periodic Error for PMSM Drives
    • Authors: Dongdong Chen;Jian Li;Junhua Chen;Ronghai Qu;
      Pages: 5990 - 6000
      Abstract: Accurate rotor position plays a critical role in field-oriented control of permanent magnet synchronous machines (PMSMs). However, the resolver periodic error has posed great challenges to the control process. It can be interpreted that the periodic position error will lead to a distinction between the stator currents fed back to the current controller and the real stator currents, generating current harmonics and torque ripples in PMSMs. This article proposes a novel method for on-line compensation of resolver periodic error based on model reference adaptive system and phase-locked loop. The principle of the novel method is elaborated, in which a reference model and an adaptive model are constructed. The reference current vector representing the fundamental current is generated by the reference model. The adaptive current vector reflecting the harmonic current is generated by the adaptive model. The cross product of reference and adaptive current vectors is implemented to obtain the information of the position error. The output of the adaptive model is adapted to the output of the reference model. The periodic error is compensated in the adaptive process. The control system of the PMSM, including the compensation method, is introduced in this article. The feasibility and reliability of the proposed on-line compensation method is verified by simulation and experiments.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Performance Improvement of Model Predictive Current Control of
           Fault-Tolerant Five-Phase Flux-Switching Permanent Magnet Motor Drive
    • Authors: Wentao Huang;Wei Hua;Fuyang Chen;Ji Qi;Jianguo Zhu;
      Pages: 6001 - 6010
      Abstract: To improve the fault-tolerant performance of a five-phase flux-switching permanent magnet (FSPM) motor drive under open-circuit fault (OCF) condition, a model predictive current control (MPCC) with pre-selective method and duty ratio control (DRC) technology is proposed and investigated in this paper. First, on the principle of minimizing harmonic voltages in x-y subspace, two zero switching states and the switching state, which generates a larger voltage vector in α-β subspace are pre-selected. Second, voltage vector references in α-β subspace and x-y subspace are predicted to further select active voltage vector candidates. Consequently, the number of current predictions has been significantly reduced, resulting in the alleviation of the computational complexity and the increase of sampling frequency. Third, the DRC approach is applied in conjunction with the pre-selection-based MPCC to improve the steady-state performance. Finally, the effectiveness of the proposed MPCC method for the OCF tolerant five-phase FSPM motor drive is validated by comparative experiments.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • A Novel Online Current- and Voltage-Sensor Offset Adaption Scheme
           Utilizing the Effect of Inverter Voltage Distortion
    • Authors: Michael Schubert;Daniel Scharfenstein;Rik W. De Doncker;
      Pages: 6011 - 6017
      Abstract: Electrical drive systems without dedicated speed transducer require precise information about the terminal phase voltage to achieve an acceptable low-speed performance. Recently, voltage-sensing techniques have gained in importance as they improve stability at low-speeds compared to the conventional estimation based on reference values. However, the additional sensors increase the sensitivity to sensor offset drift, which can cause self-sensing control algorithms to fail at very low speeds. In this article, a novel offset adaption method is introduced that compensates sensor offsets during operation while being fully decoupled from the control algorithm. Using a pair of phase current and voltage sensors per phase, the dead-time-related inverter voltage-distortion curve is monitored continuously. Its point-symmetrical nature is utilized for the sensor offset detection. This way, both sensor offsets can be calibrated continuously during operation and for each phase individually. This article gives a step-by-step description of the calibration algorithm and addresses implementation aspects to ensure deterministic calibration dynamics. The method is evaluated through measurements performed on a test bench for an electric-vehicle traction drive.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Analysis and Detection of Electrical Aging Effects on High-Speed Motor
    • Authors: Riccardo Leuzzi;Vito Giuseppe Monopoli;Luca Rovere;Francesco Cupertino;Pericle Zanchetta;
      Pages: 6018 - 6025
      Abstract: The use of fast wide-bandgap devices in high-speed electrical drives with steep pulsewidth modulation voltage waveforms is the main cause of increased stress on the electric machine insulation system and consequently, of reduced reliability of the whole system. This represents a major concern in safety-critical applications, such as in the aerospace and electric transportation fields. The novel contribution of this work is to assess the effects of electrical aging on complex insulation systems (i.e., a whole stator winding) by analyzing easily measurable macroscopic quantities. To this purpose, an electrical aging procedure is defined, and the effects produced on three tested motors are presented. Three different analysis methods are adopted with the aim of assessing the damage caused to an ac motor winding by such steep voltage waveforms and hence to evaluate the state of aging of the insulation system.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Voltage Autobalance Characteristic Analysis and Clamp Circuits Design of
           Hybrid-Clamped Three-Level LLC Converter
    • Authors: Lin Shi;Bangyin Liu;Shanxu Duan;Jian He;Tao Cai;Jieyi Sun;Wanxing Sheng;
      Pages: 6026 - 6035
      Abstract: The operating principle of the clamp circuits like clamping diodes and flying capacitor in three-level LLC converter is different from other three-level converters, because the mean value of the resonant tank current is always zero and pulse-frequency modulation control is generally used instead of pulsewidth modulation control. And the converter with only the clamping diodes or flying capacitor is difficult to realize voltage balance. In this paper, the characteristics of the three-level LLC converter with single clamp circuit are first analyzed. Then, the operation principle of the hybrid-clamped circuit under the unbalanced voltages on input capacitors is described with the mode analysis, based on which the mechanism for voltage autobalance is elaborated and the effects of two clamp circuits are derived. Then, the design of the clamping diodes and the flying capacitor is also involved. Finally, a three-level LLC converter prototype is built and the experimental results verify the validity of the theoretical analysis and design.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • A Signal Conditioning Antiwindup Approach for Digital Stationary Frame
           Current Regulators
    • Authors: Brendan Peter McGrath;Donald Grahame Holmes;Luke McNabb;
      Pages: 6036 - 6046
      Abstract: AC current regulators are susceptible to controller windup, i.e., the condition in which the controller dynamic states ramp the controller output up to very large values when the commanded reference cannot be achieved because of inverter saturation. Recovering from saturation can take considerable time once the linear mode has been restored, which degrades the current regulator's transient performance and can also impact on its stability. This paper proposes an improved formulation using the concept of signal conditioning, where windup is avoided by feeding the controller states entirely from the constrained inverter pulsewidth modulation command. Unlike previous approaches, this technique has the benefit of a simplified realization, since the controller transfer functions do not require algebraic reformulation. This makes it particularly suitable for multiple cascaded resonators used in harmonic compensation systems. The technique has been validated using simulation and experimental investigations for a grid-connected inverter.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Hybrid Asymmetric Cascaded Multilevel Inverters Based on Three- and
           Nine-Level H-Bridges
    • Authors: Filipe Antônio da Costa Bahia;Cursino Brandão Jacobina;Nady Rocha;Italo Roger Ferreira Moreno Pinheiro da Silva;Reuben Palmer Rezende de Sousa;
      Pages: 6047 - 6060
      Abstract: This paper proposes two hybrid asymmetric cascaded multilevel inverters for driving medium-voltage open-end winding motors. Each phase of the proposed systems consist of a three-level (3L) H-bridge cell and a nine-level (9L) H-bridge cell connected in series. An unequal dc-voltage ratio of 1:8 between cells is used, providing 19 phase voltage levels. The topologies of the 9L H-bridge cell are based on modular multilevel cascade converter (MMCC) with double-star chopper cells, while the 3L H-bridge cell is fed by a floating capacitor. Compared to conventional MMCC for open-end stator winding motor drives, the proposed inverters can produce more phase voltage levels. In addition, they require a smaller number of power semiconductor switches, drivers and capacitors. Simulations and experimental results are presented in order to demonstrate the performance and feasibility of the proposed topologies.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Current Stress Reduction for DC-Link Capacitors of Three-Phase VSI With
           Carrier-Based Continuous PWM
    • Authors: Koroku Nishizawa;Jun-ichi Itoh;Akihiro Odaka;Akio Toba;Hidetoshi Umida;Satoru Fujita;
      Pages: 6061 - 6072
      Abstract: This article proposes a novel continuous pulsewidth modulation (CPWM) method to reduce dc-link current harmonics in voltage source inverters over wide range of load power factor. This modulation method contributes to a current stress reduction of dc-link smoothing capacitor and a suppression of its temperature rise. Furthermore, high-cost digital hardware, such as a field-programmable gate array, is not necessary because this modulation is implemented with only one carrier. The dc-link current harmonics are reduced by shifting voltage references in every half control period to reduce a fluctuation of the dc-link current around its average value. Experimental results confirm that the application of the proposed CPWM reduces the dc-link current harmonics by 24.2% at most and lowers an equilibrium capacitor temperature by 6.0 °C compared to the conventional CPWM.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • A Seven-Level VSI With a Front-End Cascaded Three-Level Inverter and
           Flying-Capacitor-Fed H-Bridge
    • Authors: Tirupathi Abhilash;Kirubakaran Annamalai;Somasekhar Veeramraju Tirumala;
      Pages: 6073 - 6088
      Abstract: Multilevel inverters (MLIs) are playing a pivotal role in the power sector with potential applications, such as interfacing renewable energy sources with the grid and several industrial drive applications. MLIs with a smaller number of switching devices are more promising due to their compact size, reduced cost, and higher efficiency compared with their traditional counterparts. This paper, therefore, presents a new three-phase seven-level inverter. This topology is a combination of two cascade-connected two-level voltage-source inverters (VSIs) and H-bridge cells with flying capacitors (FCs). This paper presents the operating principle and the balancing technique for the dc-link capacitors and FCs. The generation of various output voltage levels and the limitation of the sinusoidal pulsewidth modulation control for FC voltage balancing is also presented. The number of components in the proposed circuit configuration and their voltage ratings are considerably lower compared with the recently proposed topologies. The behavior of the proposed circuit configuration is first assessed with simulation studies and is then tested with a laboratory prototype. The simulation and experimental results validate the effectiveness of the proposed topology and the voltage balancing technique.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Experimental Validation of a Novel Method for Harmonic Mitigation for a
           Three-Phase Five-Level Cascaded H-Bridges Inverter
    • Authors: Giuseppe Schettino;Fabio Viola;Antonino Oscar Di Tommaso;Patrizia Livreri;Rosario Miceli;
      Pages: 6089 - 6101
      Abstract: In modern high-power electrical drives, the efficiency of the system is a crucial constraint. Moreover, the efficiency of power converters plays a fundamental role in modern applications requiring also a limited weight, such as the electric vehicles and novel more electric aircraft. The reduction of losses pushes for systems with a dc bus and a high number of dc/ac converters, widespread in the vehicle, not burdened by a too expensive data processing system. The purpose of this article is to concur to reduce losses by proposing an innovative selective harmonic mitigation method based on the identification of the working areas where the reference harmonics present lower amplitudes. In particular, the main objective is to find a new way to calculate the control angles in real-time operation without solving nonlinear equations, whose resolution would require expensive controllers. Through a very simple approach, the polynomial equations, which drive the control angles, were detected for a three-phase five-level cascaded H-bridge inverter and implemented in a digital system to real-time operation with a low computational cost. As a result, a comparison between the simulation and experimental behavior is presented. In the last part of this article, a real electric machine is driven by considering the appropriate working areas and current harmonics are also evaluated.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • An Output Ripple-Free Fast Charger for Electric Vehicles Based on
           Grid-Tied Modular Three-Phase Interleaved Converters
    • Authors: Klemen Drobnic;Gabriele Grandi;Manel Hammami;Riccardo Mandrioli;Mattia Ricco;Aleksandr Viatkin;Marija Vujacic;
      Pages: 6102 - 6114
      Abstract: An off-board dc fast battery charger for electric vehicles (EVs) with an original control strategy aimed to provide ripple-free output current in the typical EV batteries voltage range is presented in this article. The proposed configuration is based on modular three-phase interleaved converters and supplied by the low-voltage ac grid. The ac/dc interleaved three-phase active rectifier is composed of three standard two-level three-phase converter modules with a possibility to slightly adjust the dc-link voltage level in order to null the output current ripple. A modular interleaved dc/dc converter, formed by the same three-phase converter modules connected in parallel, is used as an interface between the dc link and the battery. The use of low-cost, standard and industry-recognized three-phase power modules for high-power fast EV charging stations enables the reduction of capital and maintenance costs of the charging facilities. The effect of coupling on the individual input/output inductors and total input/output current ripples has been investigated as well, considering both possible coupling implementations, i.e., inverse and direct coupling. Numerical simulations are reported to confirm the feasibility and the effectiveness of the whole EV fast charging configuration, including the proposed control strategy aimed to null the ripple of the output current. Experimental results are provided by a reduced scale prototype of the output stage to verify the ripple-free output current operation capability.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • A DC-Link Capacitor Voltage Ripple Reduction Method for a Modular
           Multilevel Cascade Converter With Single Delta Bridge Cells
    • Authors: Takaaki Tanaka;Huai Wang;Frede Blaabjerg;
      Pages: 6115 - 6126
      Abstract: This article proposes a capacitor voltage ripple reduction method used for a modular multilevel cascade converter (MMCC) with single delta bridge cells (SDBC), by applying a third harmonic zero-sequence current. A practical case study on an 80 MVar/33 kV MMCC-SDBC-based STATCOM is used to demonstrate the method. The impact of the third harmonic zero-sequence current level of the capacitor ripple reduction and the electrothermal stresses on insulated gate bipolar transistor modules are analyzed. An optimal parameter of the current level is obtained by compromising the above-mentioned performance factors. The obtained result shows that the required capacitance, as well as the capacitor bank volume, is reduced by 20% without increasing the total power semiconductor losses by using the proposed method.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Improving Low-Voltage DC Circuit Breaker Performance Through an Alternate
           Commutating Circuit
    • Authors: Sudipta Sen;Shahab Mehraeen;
      Pages: 6127 - 6136
      Abstract: Current interruption in dc circuits is more challenging than in their ac counterparts due to the absence of natural current zero-crossing and resistive nature of the dc grids. This article summarizes the current dc breaker technologies and proposes new alternate methods for low-voltage applications. The proposed mechanisms utilize two switches, of which one generates zero crossing with an alternate oscillatory circuit for the other one, which can be a conventional ac breaker and is used in the main circuit. This is different than the conventional single-switch commute-and-absorb method used in high-voltage dc systems. It is shown that the proposed oscillatory circuit improves the fault current extinction and significantly reduces the voltage slew rate of conventional mechanical and solid-state switches. Thus, the proposed mechanism is capable of interrupting high dc currents with a minimal arc through a less expensive ac circuit breaker. Simulation and hardware results are provided to show the efficiency of the proposed breakers.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Model Predictive Control Based on Optimized Pulse Patterns for Modular
           Multilevel Converter STATCOM
    • Authors: Vedrana Spudić;Tobias Geyer;
      Pages: 6137 - 6149
      Abstract: This article considers a medium-voltage static synchronous compensator (STATCOM) that is based on a delta-connected modular multilevel converter (MMC) and operates at switching frequencies of 150 Hz or less. Offline computed optimal pulse patterns (OPPs) facilitate the shaping of the grid current spectrum at such low switching frequencies. However, STATCOM applications require the injection of harmonics and negative-sequence currents, as well as fast power transients. In order to achieve this, a model predictive controller is designed, which modifies the switching transitions of the OPPs, inserts additional pulses if required, and controls the circulating current in the delta-connected MMC.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • A Low THD Three-Level Rectifier For Gen-Set Applications
    • Authors: Salvatore Foti;Antonio Testa;Giacomo Scelba;Valerio Sabatini;Alessandro Lidozzi;Luca Solero;
      Pages: 6150 - 6160
      Abstract: A low input current total harmonic distortion (THD) rectifier is presented, tailored around an open-end winding permanent magnet synchronous generator. Specifically, a six-level converter topology is obtained by connecting the generator stator winding to a three level T-type unidirectional rectifier on one side, and to an auxiliary two-level inverter on the other side. The T-type rectifier manages the entire active power stream and operates at the line frequency in order to minimize the switching power losses. The auxiliary inverter is instead driven by a standard PWM technique, being tasked to sinusoidally shape the input current and to actively balance the voltage across the dc-bus capacitors of the T-type rectifier. Such an inverter, being rated at a lower power and at a lower voltage than the T-type rectifier, can exploit low-cost power mosfets. The proposed topology, featuring a very low input current THD, could well supplement in aircraft, portable or distributed generation applications, modern high-speed permanent magnet synchronous generators featuring a quite small stator impedance. Simulation and experimental results confirm the effectiveness of the proposed configuration.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Frequency-Domain Electrothermal Impedance Spectroscopy of an Actively
           Switching Power Semiconductor Converter
    • Authors: Timothy A. Polom;Markus Andresen;Marco Liserre;Robert D. Lorenz;
      Pages: 6161 - 6172
      Abstract: This paper develops impedance spectroscopy for characterizing transient heat transfer in assembled power semiconductor converter systems. The method addresses limits associated with traditional methods, for e.g., data sheet transient thermal impedance curves are step responses that only characterize the junction-to-case spatial-domain segment. The presented method utilizes an actively switching semiconductor as a controlled modulator of dynamic loss (heat) injections, along with multiple temperature measurements, to form spatial electrothermal impedance frequency response function (FRF) models. Complementary investigations of numerical and analytical modeling methods yield a general, compact thermal model template, for interpreting measured FRFs. A pulsewidth modulated power converter with integrated die and heat sink temperature sensing was characterized with the spectroscopy method. Obtained ambient-referred and relative FRFs describe transient heat transfer, including fast (die-level) and slow (sink-level) modes, over frequency decades with coherence. The FRFs were parameterized and interpreted using the derived compact thermal model.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • A Temperature-Suppression Charging Strategy for Supercapacitor Stack With
           Lifetime Maximization
    • Authors: Yongjie Liu;Zhiwu Huang;Hongtao Liao;Chengzhang Lyu;Yanhui Zhou;Yun Jiao;Heng Li;Chao Hu;Jun Peng;
      Pages: 6173 - 6183
      Abstract: It is expected, the growing demand for supercapacitor energy storage system (ESS) in which thousands of supercapacitor cells are connected as a stack for meeting the desired load power. The lifetime of ESS dramatically depends on the operating thermal effects of individual cells. In this paper, a temperature-suppression charging strategy is proposed for supercapacitor ESS to maximize its lifetime. First, the charging current and equivalent series resistance (ESR) construct the supercapacitor thermal model, and the ESR represents the degradation degree of the supercapacitor. Second, the maximization of system lifetime and equalization of unit degradation degree jointly form a convex optimization problem with the charging time constraint. The optimization problem is solved to obtain the equivalent charging current, which is realized through pulse width modulation (PWM) digital control. Simulation and experimental results show that the proposed method has the advantages of reducing ESS operating temperature and maximizing its lifetime.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Wear-Out Condition Monitoring of IGBT and mosfet Power Modules in
           Inverter Operation
    • Authors: Fernando Gonzalez-Hernando;Jon San-Sebastian;Asier Garcia-Bediaga;Manuel Arias;Francesco Iannuzzo;Frede Blaabjerg;
      Pages: 6184 - 6192
      Abstract: In this article, a condition monitoring system for the degradation assessment of power semiconductor modules under switching conditions is presented. The proposed monitoring system is based on the online measurement of two damage indicators: the on-state voltage of the semiconductor and the voltage drop in the bond wires. The on-state voltage of a semiconductor can be employed for temperature estimation, in order to anticipate failures in the solder joints that increase the thermal resistance of the cooling path. Moreover, by measuring the voltage drop in the bond wires, the degradation of the bond wires can be detected. The described monitoring system has been implemented in an inverter prototype, and tests have been performed in different scenarios to verify its capabilities in healthy and degraded states. Furthermore, a monitoring routine has been proposed in order to perform the required measurements in high switching frequency applications.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Grid Integration of Three-Phase Single-Stage PV System Using Adaptive
           Laguerre Filter Based Control Algorithm Under Nonideal Distribution System
    • Authors: Pavitra Shukl;Bhim Singh;
      Pages: 6193 - 6202
      Abstract: The increasing integration of utility with renewable sources of energy has resulted into serious issues of power quality (PQ) deterioration primarily in a scenario of weak distribution grid. In order to improve the PQ, efficient implementation of a control algorithm for the solar energy conversion system interfaced to the grid is paramount. This article illustrates the usage of an adaptive Laguerre filter based control technique for optimal operation providing distribution static compensator capabilities along with load balancing, power factor correction and harmonics mitigation. Moreover, it provides the active power transfer to the grid together with feeding the nonlinear and linear loads. In addition, the system performance according to an IEEE-519 standard has been verified, hence it is proficient in maintaining the PQ. The Laguerre filter offers the benefits of reduced computational time in addition with the alleviation in model complexity predominant during abnormal grid conditions. By utilizing maximum power point tracking, the efficient utilization of solar PV array is accomplished with a perturb and observe method. For validating performance of the proposed system, it is examined through simulation results. Furthermore, a prototype is developed for validation and test results corroborate reliable operation under nonideal grid conditions comprising of wide range of load variations, voltage sag, swell, distortion, and unbalance conditions.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • A General Approach to Select Location and Ratings of Energy Storage
           Systems in Local Area Energy Networks
    • Authors: Paolo Tenti;Tommaso Caldognetto;
      Pages: 6203 - 6210
      Abstract: The European directive “Clean Energy for All Europeans” depicts for 2030 a new scenario for low-voltage distribution grids, where each end user will have the right to trade energy and offer demand response in the electrical market either individually or in aggregation with others. This creates a new perspective for renewable energy sources (RESs) and energy storage systems (ESSs), which become key elements to allow end users playing a substantial role in the electrical market. While many distributed RESs are already in place in low-voltage grids, the ESSs are still in infancy and will become a crucial asset of future microgrids. The optimal selection of ESS ratings and location within an energy network is still an open problem, and its solution can impact considerably the grid performance and return of investment for energy sources and distribution infrastructure. This paper presents a general methodology to select the best location and ratings of energy storage units complying with the needs of local area energy networks. The aim is to support end users and aggregators to plan their investments and operate the grid so as to attain the role and functionality envisioned by the European directive.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • VSC Control of Grid Connected PV for Maintaining Power Supply During
           Open-Phase Condition in Distribution Network
    • Authors: Surya Prakash;Sukumar Mishra;
      Pages: 6211 - 6222
      Abstract: The grid-connected photovoltaic (PV) system with battery energy storage (BESS) has been in use for many demand-related issues. This article discusses the use of grid-connected PV with BESS in case of open-phase condition in the distribution system. An open-phase condition at medium voltage (11 kV) will result in continuous voltage sag at low voltage (LV) voltage level (400 V), which may be detrimental to various kind of loads, especially for constant power loads. This article presents an approach to mitigate such a scenario by using a control strategy for voltage source converter of grid-connected PV connected to the distribution transformer terminal. The utility of the proposed configuration is demonstrated as the voltage is restored in all phases at the LV level during an open-phase fault at the MV level, and results obtained for selected possible loading conditions have been presented. For further validating the proposed control strategy in real-time conditions, experimental verification is also done on an NI-based PXI hardware setup along with an Opal-RT based hardware in the loop system, and results for the same have been presented.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • A Rotational Control in Medium-Voltage Modular Solid-State
           Transformer-Based Converter System
    • Authors: Dong Dong;Ravisekhar Raju;Govardhan Ganireddy;Mohammed Agamy;
      Pages: 6223 - 6233
      Abstract: This paper presents a novel control strategy to significantly reduce the high-frequency transformer loss in a modular solid-state transformer (SST) based converter system. The modular SST design is based on an ac-dc power-electronic building block comprised of an H-bridge at the ac input and a bidirectional soft-switching isolated dc-dc converter with a medium-voltage insulated high-frequency transformer. The ac terminals of input H-bridges are connected in series and directly coupled to the medium-voltage ac line, while the output dc terminals are all connected in parallel at a low voltage. The key innovation described in this paper, without sacrificing the output performance, is the control scheme that reduces core and winding losses associated with the dc-dc resonant stage by turning off the selected dc-dc converters in synchronism with the line voltage. The prototype for the test described in this paper is based on a modular SST where each module is rated at 50 kVA, with a 200 kHz transformer using 1.7 kV silicon carbide discrete mosfets, but the described control concepts are more broadly applicable to similar topologies.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Dynamic Modeling and Analysis of Buck Converter Based Solar PV Charge
           Controller for Improved MPPT Performance
    • Authors: D. Venkatramanan;Vinod John;
      Pages: 6234 - 6246
      Abstract: Maximum power point tracking (MPPT) control is a key functionality in solar photovoltaic (PV)-based power conversion systems. A variety of perturbative MPPT control schemes are available in the literature, many of which are voltage-based techniques wherein the PV bus voltage is perturbed and set to the required level by an appropriate converter control that achieves the MPP tracking. However, a comprehensive plant model of the PV-fed converter system and a systematic control design of the PV bus voltage loop that facilitates the design of the MPPT control is not available in the literature. In this article, a detailed small-signal model is proposed for a single-stage PV-fed buck converter that acts as a battery charge-controller. The effects of parasitic storage elements present in the PV source as well as the interconnecting cable from rooftop are discussed in detail, along with the impact of series-parallel connection of the PV modules for power scaling. A full-order as well as a reduced-order model of the system is proposed and the various relevant transfer-functions are analytically derived. Based on this model and the control to converter input bus voltage transfer-function ṽin/d̃, a systematic design procedure for the PV bus voltage controller is proposed. It is shown that such a design facilitates the selection of perturbation period of a typical MPPT control algorithm for an improved tracking performance. The steps involved in the system model development and the control design are generalized and can be extended to other converter topologies as well. Active transfer-function measurements and experiments conducted on a 1-kW charge-controller hardware prototype validate the accuracy of the proposed model and the tracking performance of the MPPT control.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • A Novel Electrical Model for Iron Doped-Sodium Metal Halide Batteries
    • Authors: Mauro Boi;Daniele Battaglia;Andrea Salimbeni;Alfonso Damiano;
      Pages: 6247 - 6255
      Abstract: A novel electrical model, able to mimic the dynamic behavior of iron-doped sodium metal halide batteries (SMHBs), is reported in this article. The proposed SMHB model is a development of Thévenin-based configuration. Specifically, the model is integrated such that additional components reproduce accurately the SMHB electrochemical phenomena occurring during the discharge and charge processes. The methodology used for identification of the parameters of the proposed SMHB equivalent circuit is reported and experimentally validated. In order to highlight the improvements achieved, a comparison between the experimental and the simulated results of different SMHB electrical models was performed. The proposed model showed a significant improvement in the state of charge range of 40%-10%, with estimation errors, with respect to the experimental results, of less than 1%. Outcomes achieved by the proposed SMHB model open new opportunities for the exploitation of this class of battery for power system applications.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • A 50-kW Air-Cooled SiC Inverter With 3-D Printing Enabled Power Module
           Packaging Structure and Genetic Algorithm Optimized Heatsinks
    • Authors: Zhiqiang Wang;Madhu Chinthavali;Steven L. Campbell;Tong Wu;Burak Ozpineci;
      Pages: 6256 - 6265
      Abstract: This article presents a systematic power stage design approach for a high-power density air-cooled inverter, which involves the utilization of emerging 1.7 kV silicon carbide (SiC) mosfet bare die engineering samples, heatsinks optimized with genetic algorithm, and built using three-dimensional printing technology and integrated power modules with a novel packaging structure. The developed air-cooled inverter assembly is mainly composed of the SiC mosfet phase leg modules with split high-side and low-side switch submodules, which are attached to two separate heatsinks for increased heat dissipation area and reduced thermal resistance. The heatsink is designed using a co-simulation environment with finite element analysis in COMSOL and genetic algorithm in MATLAB. The primary design procedure, including bare die device characterization, loss calculation, thermal evaluation, and power module development, is elaborated. The proposed design approach is verified and validated through experiments at each stage of development. The experimental results show that the inverter California Energy Commission efficiency is 98.4%, and a power density of 75 W/in3 is achieved with a sufficient junction temperature margin for semiconductor long-term reliability.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • A Predictive Set-Point Modulation Energy Management Strategy for Hybrid
           Energy Storage Systems
    • Authors: Yanhui Zhou;Zhiwu Huang;Hongtao Liao;Heng Li;Yun Jiao;Jun Peng;
      Pages: 6266 - 6277
      Abstract: In the hybrid energy storage system of electric vehicles, the main objective is to guarantee that the dc-bus voltage tracks the desired set point quickly and accurately. However, it is typically difficult for existing methods to provide both short settling time and small overshoot, which results in significant dc-bus voltage fluctuations. To address this issue, in this paper, we propose a predictive-set-point-modulation-based energy management control strategy. A lead-compensator-based predictive set-point modulation method is designed and integrated in the voltage control loop to improve the response speed. Theoretical analysis is carried out for the energy management system, and an explicit expression of the control parameters is derived. Moreover, an adaptive cutoff-frequency-based power allocation approach is proposed to guarantee that supercapacitors (SCs) can provide sustainable power supply in the long term. A laboratory testbed is built to verify the effectiveness of the proposed method. Experiment results show that the proposed method provides a lower dc-bus voltage fluctuation, higher SC capacity utilization, and a better protection for batteries, when compared with the conventional method.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • A Power-Factor-Corrected LLC Resonant Converter for Electric Vehicle
           Charger Using Cuk Converter
    • Authors: Rahul Pandey;Bhim Singh;
      Pages: 6278 - 6286
      Abstract: This article presents an improved power quality Cuk-converter-fed isolated LLC resonant converter for an electric vehicle battery charger (EVBC), intended typically to charge a small two- or three-wheel-driven electric vehicle (EV) using up to 20-Ah battery. The proposed topology consists of two converters, comprising of the first stage for power factor correction (PFC) and the second stage for effective charging of the EV battery using a constant-voltage and constant-current mode control algorithm. In the first stage, the Cuk converter performs PFC by operating in the continuous conduction mode of the primary inductor, while the LLC resonant converter converts the dc-link voltage to the isolated dc voltage required for the EVBC. The proposed converter uses a frequency control algorithm to actively vary the intermediate dc-link voltage based on the state of charge of the battery leading to reduced turn-off losses in the LLC converter switching devices. The proposed converter is designed and simulated in MATLAB. Simulated results are analyzed and discussed in detail. Finally, a 580-W 10-A experimental prototype of the EVBC is developed, and test results are presented to demonstrate the effectiveness of the proposed topology. The proposed converter exhibits excellent power quality indices adhering to the IEC-61000-3-2 international standard.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Prevention of Back Corona Discharge in an Electrostatic Precipitator Using
           Asymmetrical Rectangular AC Voltage
    • Authors: Tomoya Mitsui;Akinori Zukeran;Koji Yasumoto;Takashi Nakano;Koyu Tsubouchi;Takashi Ogawa;
      Pages: 6287 - 6294
      Abstract: The aim of this article is to prevent back corona discharge using asymmetrical rectangular ac voltage. The experimental electrostatic precipitator (ESP) consisted of a high-voltage application wire electrode and a grounded plate electrode with a gap in between. Calcium carbonate dust was placed on the surface of the grounded plate electrode. Dc, symmetric, or asymmetric rectangular ac voltage was applied to the wire electrode. The voltage waveform and the current waveform were measured, and a photograph of discharge luminescence on the surface of the dust layer was taken by a digital camera. When dc high voltage was applied, the discharge current increased, and the discharge luminescence was observed on the surface of the dust layer due to back corona discharge. On the other hand, the discharge current did not increase and discharge luminescence was not observed, when the symmetrical ac high voltage at the period of 4 ms was applied. However, the application time of the positive polarity was equal to the negative polarity, and the period was short. Accordingly, it is expected that the collection efficiency is not high in the symmetrically energized ESP. Thus, the effect of an asymmetrical ac energization was investigated. The result showed that the back corona discharge was avoided in the ESP energized by an asymmetrical rectangular ac high voltage with a period of 9 ms including a positive period of 7 ms and negative period of 2 ms.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Pilot-Scale NOx and SOx Aftertreatment Using a Two-Phase Ozone and
           Chemical Injection in Glass-Melting-Furnace Exhaust Gas
    • Authors: Hashira Yamamoto;Tomoyuki Kuroki;Hidekatsu Fujishima;Masaaki Okubo;
      Pages: 6295 - 6302
      Abstract: As NOx and SOx have significant environmental impacts, advanced treatments are required to remove them from the exhaust gas of a glass melting furnace. Here, we investigate a plasma-chemical hybrid process (PCHP) for this purpose. A pilot-scale experiment of the simultaneous removal of NOx and SOx using a PCHP combined with the existing semi-dry type desulfurization reactor is conducted on actual high-temperature exhaust gas from a glass melting furnace. NO (the majority of NOx exist as NO) in the exhaust gas is oxidized to NO2 using active oxygen (ozone: O3) generated by a plasma ozonizer. The exhaust gas must be cooled to less than 150 °C in order to suppress the thermal decomposition of O3, while the gas temperature at the outlet of the semi-dry reactor must be kept at 200-;250 °C to protect the dry-type electrostatic precipitator. Therefore, it is important to form a local cooling area for NO oxidation in the reactor. In this article, we use the three-fluid nozzles of O3, water, and air to form the local cooling area and effectively oxidize NO to NO2. In addition, we spray NaOH aqueous solution for SO2 absorption downstream of the NO oxidation area to allow sufficient time for NO oxidation. The SO2 reacts with NaOH to produce Na2SO3, a powerful reducing agent. Subsequently, NO2 reacts with Na2SO3 and is reduced to N2, and the Na2SO4 generated in this reaction is reused as a clarifier of the raw materials for glass manufacturing. As a result, the ratio of the amount of removed NO and NOx to the amount of injected O3 (de-NO/O3 and de-NOx/O3) is 64% and 78%, respectively; therefore, high efficiency is obtained. This article includes -ctual examples of the treatment of exhaust gas in a glass melting furnace, using PCHP de-SOx and de-NOx technologies along with results from pilot-scale experiments.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Measuring and Enhancing Microgrid Resiliency Against Cyber Threats
    • Authors: Venkatesh Venkataramanan;Anurag K. Srivastava;Adam Hahn;Saman Zonouz;
      Pages: 6303 - 6312
      Abstract: Recent cyber attacks on the power grid have been of increasing complexity and sophistication. In order to understand the impact of cyber-attacks on the power system resiliency, it is important to consider an holistic cyber-physical system specially with increasing industrial automation. In this study, device-level resilience properties of the various controllers and their impact on the microgrid resiliency is studied. In addition, a cyber-physical resiliency metric considering vulnerabilities, system model, and device-level properties is proposed. Resiliency is defined as the system ability to provide energy to critical loads even in extreme contingencies and depends on system ability to withstand, predict, and recover. A use case is presented inspired by the recent Ukraine cyber-attack. A use case has been presented to demonstrate application of the developed cyber-physical resiliency metric to enhance situational awareness of the operator, and enable better proactive or remedial control actions to improve resiliency.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Cyber Physical Security Analytics for Anomalies in Transmission Protection
    • Authors: Arman Ahmed;Vignesh V. G. Krishnan;Seyedeh Armina Foroutan;Md. Touhiduzzaman;Caroline Rublein;Anurag Srivastava;Yinghui Wu;Adam Hahn;Sindhu Suresh;
      Pages: 6313 - 6323
      Abstract: Protection systems are one of the most critical components in the transmission system and are becoming more digital with ongoing automation. These digital systems are prone to vulnerabilities/attacks, and exploitation of these vulnerabilities may cause major impacts on the electric grid performance. Multiple alarms reported in the control center could be a result of the faults (expected operations) or failures in the protection system (anomalies/ unexpected operation). Situational awareness gained through sensors such as a phasor measurement unit (PMU) and data acquired through the cyber system provide an opportunity to develop continuous cyber-physical monitoring of the system. Note that relay data are not reported in the control center continuously. This paper presents a cyber-physical data analytics based technique to monitor transmission protection system and detect malicious activity. Initially, continuous monitoring of PMU data is utilized for data anomaly detection, which includes bad or missing data using long short-term memory (LSTM). Then, PMU data of interest are utilized for failure diagnosis, using a semisupervised deep autoencoder model. In this research, cyber anomalies are modeled by manipulating the setting/logic design of protective devices, and a ridge regression based classifier with a feature engineering pipeline is used to detect cyber anomalies. The results from the deep autoencoder model and ridge regression based classifier are then utilized for detailed investigation to find the root causes of the observed events assisted by the cyber log data from the protection devices. The algorithm is validated using a real-time simulation of the IEEE test system with industrial hardware relays and PMUs in the loop. Data analytics algorithm running on server utilizes these real-time data continuously for anomaly detection and classification for the developed use cases.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Topology-Based Evaluation for Symbolic Indoor Positioning Algorithms
    • Authors: Judit Tamas;Zsolt Toth;
      Pages: 6324 - 6331
      Abstract: Smart factories require location aware services such as asset tracking. These location aware services should be based on indoor positioning systems. Symbolic indoor positioning is considered as a classification task, where each category denotes a well-defined part of the building, such as a room or corridor. Hence, standard classifiers can be applied to symbolic indoor positioning. A topology-based classification evaluation method is presented that calculates the classification error based on the gravitational force between the symbolic positions denoted by categories. Three variants of the proposed topology-based method is evaluated and compared to the CRISP approach. The comparison was performed over a dataset recorded in a three-storey building whose topology is given in Indoor Geographic Markup Language format. Experimental results showed that the topology-based method gives a more detailed comparison of classifiers for indoor positioning than CRISP.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • High Gain Single Ended Primary Inductor Converter With Ripple Free Input
           Current for Solar Powered Water Pumping System Utilizing Cost-Effective
           Maximum Power Point Tracking Technique
    • Authors: Anjanee Kumar Mishra;Bhim Singh;
      Pages: 6332 - 6343
      Abstract: This paper presents a new configuration of high gain (HG) single ended primary inductor converter (SEPIC) with a ripple-free input current to maximize the efficiency of the PV panel for standalone water pumping system (WPS). The ripple eliminating circuit combined with the HG SEPIC converter to achieve reduced ripples in photovoltaic (PV) current is independent to the duty cycle control and hence, it can be easily integrated to the main power circuit of configuration. This circuit does not need any active switches, control, or drive circuit for its execution. The ripple eliminating circuit yields a complete removal of the electrolytic capacitor connected across the PV array and significantly reduces the inductance of the HG SEPIC converter. It also improves the response and power density of the dc-dc converter. The large gain of dc-dc converter enables the use of low-voltage PV panel and minimizes the partial shading and parasitic capacitance effects on PV array source. Due to the substantial compatibility between natural characteristics of switched reluctance motor (SRM) drive and WPS, a four-phase SRM drive is utilized in the proposed scheme. In addition, a single current sensor based maximum power point tracking technique is utilized in the proposed system, which helps to reduce the cost and improve the accuracy of the overall system. Analytical, simulated, and experimental results of the developed system are presented to demonstrate the performance of the system.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • An Adaptive Resilient Control Approach for Pressure Control in Proton
           Exchange Membrane Fuel Cells
    • Authors: Alireza Abbaspour;Kang K. Yen;Parisa Forouzannezhad;Arman Sargolzaei;
      Pages: 6344 - 6354
      Abstract: This paper introduces a novel controller design for pressure control in the proton exchange membrane (PEM) fuel cells. The proposed controller can control the system under the fault/failure of the actuators. The introduced design uses an artificial neural network for online fault detection and isolation in the pressure valves of the PEM fuel cell (PEMFC). We designed a nonlinear controller based on feedback linearization technique to compensate for the fault effects in real time. We also investigated the stability of the proposed design based on the Lyapunov theory. The simulation and the hardware in the loop results clearly show that the proposed active fault-tolerant control design is able to detect, estimate, and track the PEMFC actuators faults and failure accurately, and to compensate for their negative impacts while keeping the desired control performances in real time.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Analysis of Switch Automation Based on Active Reconfiguration Considering
           Reliability, Energy Storage Systems, and Variable Renewables
    • Authors: Sérgio F. Santos;Desta Z. Fitiwi;Marco R. M. Cruz;Cláudio Santos;João P. S. Catalão;
      Pages: 6355 - 6367
      Abstract: Economic development and changing lifestyles are leading to the extensive use of energy-intensive technologies by consumers. As a result, this has led to a dramatically increased demand for electricity. In addition, the consumers' increasing demand for a more reliable and uninterrupted energy supply is posing enormous challenge for service providers. This necessitates the development of novel solutions that should be at the system operators' disposal, particularly at distribution levels. One way to partly address this concern is by automating distribution systems and equipping them with intelligent technologies-a transformation to smart distribution systems. Such a transformation should improve system reliability and operational efficiency because such systems will be capable of operating and immediately restoring discontinued service to consumers. To facilitate this, it is necessary to replace manual switches by remotely controlled ones, improving the system restoration capability, which is one of the key features of smart grids. This paper presents a new framework to determine the minimal set of switches that have to be replaced or optimally allocated in order to automate the system. This is supported by a sensitivity analysis. Different topologies are also assessed taking into account various reliability indices and power losses in system operation following the system's automation. Such an optimization work is done under a massive integration of renewable energy sources and energy storage systems. All this simultaneously addresses the economic and functional requirements of the automated system, ultimately improving system's reliability. The standard IEEE 119-bus standard system is used as a case study, where different types of loads are considered (residential, commercial, and industrial).
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Decoupling Control Scheme for VSG-WPPs to Participate in Grid Frequency
    • Authors: Jiangbei Xi;Hua Geng;
      Pages: 6368 - 6375
      Abstract: By adopting the virtual synchronous generator (VSG) scheme with the inertia emulation controller and droop controller, wind power plants (WPPs) can participate in inertial response (IR) and primary frequency regulation (PFR). According to the analysis in this article, besides the well-known dynamic coupling between the wind turbine operating point (WTOP) controller and the inertia emulation controller, there is a static coupling between the WTOP controller and the droop controller. These couplings would impair the IR and PFR characteristics of the VSG controlled WPPs (VSG-WPPs). The equivalent droop coefficient of the VSG-WPPs is no longer equal to the setting value and changes under different operation conditions. To eliminate these adverse impacts, a decoupling control scheme is proposed. According to the MATLAB simulations and real-time hardware-in-loop testing results provided in this article, under the same power disturbance, the frequency response characteristics of the WPPs with the proposed scheme are much better than the WPPs with the original scheme.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • High Gain Quasi-Mutually Coupled Active Impedance Source Converter
           Utilizing Reduced Components Count
    • Authors: Avneet Kumar;Sajid Kamal;M. Raghuram;Deepankar Deepankar;Santosh K. Singh;Xiaogang Xiong;
      Pages: 6376 - 6388
      Abstract: High voltage gain using a mutually coupled inductor network is quite popular in recent years for Z source converters. To achieve high gain, reduced number of components used is a prime challenge to improve efficiency and reduce the cost and size. In the coupled inductor network, the energy stored is twofold, hence, the effective number of components is reduced. Moreover, the boosting factor is also governed by the number of turns which again helps in reducing the number of components. In general, coupled inductor network is based on two winding transformers. However, to increase the effective number of turns, an autotransformer principle may be used where turns ratio is increased by one as compared to two winding transformers. Therefore, in this article, a coupled inductor network is proposed which is based on the autotransformer concept. The proposed converter is called as quasi-mutually coupled active impedance source converter. The proposed converter has a continuous input current which is helpful in reducing the current stress on the source. The operation, steady-state analysis and its comparison with the existing topology are discussed. Moreover, the developed topology is extended for hybrid topology. Furthermore, the converter is validated using experiment to prove its feasibility.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Advanced Robustness Control of DC–DC Converter for Proton Exchange
           Membrane Fuel Cell Applications
    • Authors: Rui Ma;Liangcai Xu;Renyou Xie;Dongdong Zhao;Yigeng Huangfu;Fei Gao;
      Pages: 6389 - 6400
      Abstract: The fuel cell output power depends highly on the random load profile, and power converters play a key role in the fuel cell power system. Robust control design of the converter can help to design online control and optimize the diagnostic method for fuel-cell-based applications. In this article, an advanced control algorithm of the dc-dc converter for the proton exchange membrane fuel cell is realized through a robustness algorithm based on flatness control and active disturbance rejection control (ADRC). Flatness control can track the power demand, and ADRC can help to estimate the total required power in real time. The effectiveness of the proposed control method is verified through a two-phase interleaved boost converter (TIBC), and results indicate that the steady-state error of TIBC's output voltage can be decreased. Besides, the proposed control scheme is not sensitive to system parameter variations, and it can balance the power among each phase accurately. Moreover, the flatness-ADRC control can guarantee the smooth output of the converter when load disturbance occurs. The simulation and experimental results all indicate that strong robustness can be obtained when compared with the conventional proportional integral control method. The simple architecture of the controller makes it easier to be implemented in real-time online applications.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Bottom-Up Load Forecasting With Markov-Based Error Reduction Method for
           Aggregated Domestic Electric Water Heaters
    • Authors: Xun Gong;Julian L. Cardenas-Barrera;Eduardo Castillo-Guerra;Bo Cao;Saleh A. Saleh;Liuchen Chang;
      Pages: 6401 - 6413
      Abstract: Domestic electric water heaters (DEWHs) can provide operational flexibility for load control due to their energy storage capacity. Load forecasting for aggregated DEWHs is important for providing information of baseline load and controlling electricity demand profile without negative impact to the normal end use. Advanced metering infrastructures nowadays provide more possibilities to further enhance forecasting with bottom-up method. This article proposes a bottom-up forecasting with Markov-based error reduction method to predict power consumption of aggregated DEWHs for multiple forecast horizons. DEWHs are randomly divided into small aggregations, whose power consumption is forecasted by independent forecast engines. In this paper, the engines are K-means and wavelet decomposition-based neural networks. After summing all forecasting of small aggregations up, a new Markov-based error reduction method is proposed to extract features in residuals and mitigate forecasting error accumulation introduced by the summation, providing opportunities to further improve forecasting accuracy for the total DEWH load. Differing from traditional Markov-based error reduction, two new compensation parameters (compensation coefficient, and compensation threshold) are proposed. They are determined by using particle swarm optimization algorithm. Experiments on real and simulated DEWH loads verified the effectiveness of the proposed forecasting method. The proposed method improved the forecast accuracy over selected benchmark algorithms by about 20% to 80%, according to four performance metrics: mean absolute error, mean absolute percentage error, root-mean-square error, normalized form RMSE. The aggregation effects on performance were also analyzed in theory and tested with simulated DEWHs, providing a good indication of the forecast dependence on the aggregation size.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Effective Utilization of Parallel-Connected Megawatt Three-Level
           Back-to-Back Power Converters in Variable Speed Pumped Storage Units
    • Authors: Karthik Desingu;Raghu Selvaraj;Thanga Raj Chelliah;Deepak Khare;
      Pages: 6414 - 6426
      Abstract: Power electronic converter plays a significant role in the hydropower generating systems of both fixed and variable speed types. These converters are used in the form of a simple rectifier for the static dc excitation in the fixed speed system and in the form of the ac excitation (ac-ac or ac-dc-ac) in the variable speed system. The parallel-connected multiple three-level neutral-point-clamped (3L-NPC) megawatt back-to-back (BTB) converters have been adopted in recently commissioned variable speed pumped storage units (VSPSU). For such configurations, reliability and efficiency are considered to be prominent. This article proposes a methodology for effective utilization of a parallel-connected BTB power converter for VSPSU of large capacity by performing the load-dependent activation /deactivation of converters. A vector control strategy for the active and reactive power deliveries of VSPSU is formulated. This article also focusses on the losses and thermal behavior of converters at different speeds of generator in accordance with water head variations. The proposed control system is designed in such a way to decrease overall losses in the power converter system. The effectiveness of the proposed method is explained on a real scale of 250-MW doubly fed induction machine with 5 × 5 MW power converters using MATLAB/PLECS software, and experimental validation is performed through a downscaled 2.2-kW laboratory prototype.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Extended State Observer Based Flatness Control for Fuel Cell Output Series
           Interleaved Boost Converter
    • Authors: Yigeng Huangfu;Qian Li;Liangcai Xu;Rui Ma;Fei Gao;
      Pages: 6427 - 6437
      Abstract: Output series interleaved boost converter (OS-IBC) has become a promising candidate for fuel cell application, due to the features of high voltage gain and low input current ripple. To achieve a satisfactory control performance for the OS-IBC, a robust dual loop control strategy is designed in this article. The designed controller comprises an inner loop dedicated to inductor current tracking and an outer loop aimed at output voltage regulation, both of which are based on flatness control. Furthermore, the extended state observers (ESO) are integrated into this control algorithm for online estimating the uncertain input voltage and output current of the equivalent converter. With this ESO, the parasitic circuit parameters are considered into the estimations, and meanwhile, the input source voltage sensor and load current sensor can be omitted. The feasibility and robustness of the designed controller have been successfully validated by simulation and experimental results obtained using a 240-W prototype converter and a dSPACE control platform.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Integrations of Neural Networks and Transient Energy Functions for
           Designing Supplementary Damping Control of UPFC
    • Authors: Hung-Chi Tsai;Jian-Hong Liu;Chia-Chi Chu;
      Pages: 6438 - 6450
      Abstract: This article presents an integrated scheme for supplementary damping control of unified power flow controllers (UPFCs) in order to mitigate low-frequency oscillations in power systems. The entire control system consists of the primary control and the supplementary control. In the primary control, the passivity-based control is considered in the current control loop of two converters for achieving more prompt and accurate dynamical responses. In the supplementary control, the transient energy function (TEF) approach will be explored first for designing the damping control of UPFCs. This control action can be considered as an extension of droop control used in the synchronous generator. In order to further cope with unmodeled dynamics of power systems and provide the online dynamic adaptation ability, neural networks approximated control actions are designated for online weight adjustments of the TEF-based supplementary control. Numerical simulations on three benchmark systems have been performed to validate the proposed control method for providing the extra damping and suppressing power swings even under severe operating conditions.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Experimental Verification of a Double-Input Soft-Switched DC–DC
           Converter for Fuel Cell Electric Vehicle With Hybrid Energy Storage System
    • Authors: Hadi Moradisizkoohi;Nour Elsayad;Osama A. Mohammed;
      Pages: 6451 - 6465
      Abstract: In the drivetrain of a fuel cell (FC)-powered electric vehicle, double-input converter plays a critical role by transferring the power from battery and FC to an ultracapacitor (UC) during acceleration and from UC to the battery during braking. As the battery and FC have unregulated low voltage, the converter should provide a high-voltage gain as well as an efficient power conversion. In this article, a double-input three-level converter composed of buck-boost-half-bridge modules is proposed for automotive applications. The proposed converter can supply the load in the absence of FC or battery. The converter takes advantage of active clamp configuration in terms of reducing the voltage stress across switches and providing soft-switching performance. Consequently, the converter's overall performance in terms of switching losses and cost can be considerably improved. The switching scheme doubles the effective switching frequency, which, in turn, reduces the size of the boost inductors to enhance power density. The operational characteristics of the converter and comparison with state-of-the-art converters are given in this article. Finally, a 4-kW, 100-kHz prototype using gallium nitride switches is implemented to validate the proposed concept.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Foreign Object Detection in Inductive Charging Systems Based on Primary
           Side Measurements
    • Authors: Hassan Jafari;Masood Moghaddami;Arif I. Sarwat;
      Pages: 6466 - 6475
      Abstract: A foreign object detection (FOD) method for inductive charging systems is introduced in this article. The proposed FOD only requires primary side measurements, i.e., primary resonant current and resonance frequency deviation. The proposed FOD incorporates a mechanism for effective discrimination of foreign object intrusion, horizontal and vertical alignment variations of the transmitter and receiver magnetic pads. Alignment variations of primary and secondary magnetic pads as well as intrusion of conductive/magnetic foreign object both impact electromagnetic characteristics, consequently the resonant frequency. FOD for large size objects works properly based on resonance frequency deviation, however, there is the need for discrimination between the FOD for small objects and misalignment. Thereby, both disturbances can be detected by online monitoring of the resonance frequency deviation, and be discriminated from each other by real-time measurement of the primary current. The proposed FOD technique can be added as a protection scheme to the self-tuning controllers of inductive power transfer (IPT) systems operating off its resonance frequency. Finite element analysis along with theoretical formulation of the studied IPT circuit is presented using the proposed method. Conductive FOD method based on frequency deviation and discrimination method using primary resonance current are implemented on an IPT setup, and the experimental results verify its effectiveness in both standby and full-power modes. The test results show that the frequency deviation based FOD method has a high speed in detection of even small scale objects such as a coin.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Interconnection and Damping Assignment Passivity-Based Control Applied to
           On-Board DC–DC Power Converter System Supplying Constant Power Load
    • Authors: Shengzhao Pang;Babak Nahid-Mobarakeh;Serge Pierfederici;Matheepot Phattanasak;Yigeng Huangfu;Guangzhao Luo;Fei Gao;
      Pages: 6476 - 6485
      Abstract: In the more electric aircraft context, dc distribution systems have a time-varying structure due to the flexible distributed loads and complex operation conditions. This feature poses challenges for system stability and increases the difficulty of the stability analysis. Besides, the risk of instability may be increased under constant power load condition due to the negative incremental impedance characteristic. To this end, this article proposes an improved interconnection and damping assignment passivity-based control scheme. Particularly, an adaptive interconnection matrix is developed to establish the internal links in port-controlled Hamiltonian models and to generate the unique control law. The damping assignment technique is addressed to tune the dynamic characteristic. In order to meet the load requirements of different voltage levels, the design procedures were given for determining the control law in both boost converter and buck converter cases. The simulation and experimental results are performed to demonstrate the validity of the proposed control approach.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • A Hybrid Firefly-Swarm Optimized Fractional Order Interval Type-2 Fuzzy
           PID-PSS for Transient Stability Improvement
    • Authors: Prakash K. Ray;Shiba R. Paital;Asit Mohanty;Y. S. Eddy Foo;Ashok Krishnan;Hoay Beng Gooi;Gehan A. J. Amaratunga;
      Pages: 6486 - 6498
      Abstract: This article focuses on the implementation of a hybrid firefly algorithm-particle swarm optimization (FAPSO) scheme for optimizing the parameters of an interval type-2 fractional order fuzzy proportional integral derivative (IT2FOFPID)-based power system stabilizer (PSS) to minimize the low-frequency oscillations in a power system. Here, the IT2FOFPID-based PSS is designed by considering speed deviation and acceleration as input signals. In this article, a single machine infinite bus system and the New England 10 machine 39-bus power system are used for testing and comparing the approaches. Stability studies are also performed using OPAL-RT's OP5600, a real-time digital simulator. The comparative studies demonstrate that the hybrid FAPSO optimized IT2FOFPID-PSS provides better damping and stability performance when compared with the PSSs based on the FA/PSO/ hybrid genetic algorithm and bacterial foraging optimization and hybrid differential evolution and pattern search optimized IT2FOFPID approaches under various operating scenarios.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Control of Hybrid Wind–Diesel Standalone Microgrid for Water
           Treatment System Application
    • Authors: Félix Dubuisson;Miloud Rezkallah;Ambrish Chandra;Maarouf Saad;Marco Tremblay;Hussein Ibrahim;
      Pages: 6499 - 6507
      Abstract: This article deals with the control of a standalone microgrid based on variable speed wind turbine (WT) and fixed speed diesel generator (DG) for water treatment application. A perturb and observe (P&O) method is used to achieve the maximum power point tracking (MPPT) from the WT without using speed sensors. Two levels of control are proposed for the three-phase voltage source inverter for voltage and frequency regulation at the point of common coupling (PCC) and power management in standalone and diesel connected modes. Furthermore, the battery energy storage is controlled using simple approach to balance the power in the system during load variations and wind speed changes. The performance of the proposed system is tested using MATLAB/Simulink under load and weather variations. In addition, the system is tested on a small-scale prototype in the laboratory under load and wind speed variations.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Optimal Power Flow Incorporating Frequency Security Constraint
    • Authors: Nga Nguyen;Saleh Almasabi;Atri Bera;Joydeep Mitra;
      Pages: 6508 - 6516
      Abstract: Optimal power flow (OPF) minimizes the production cost, while satisfying the constraints on the system, such as real and reactive power balance, equipment capability constraints, and voltage limits. This article presents a method of incorporating a frequency security constraint within the framework of the OPF problem. Increasing displacement of conventional generation by renewable resources that contribute little or no frequency regulation capability may necessitate the enforcement of such a constraint to meet frequency security requirements. The system frequency is required to be maintained within a safe limit, thus indicating the balance between generation and consumption. Hence, the solution for optimization of power flow should not only present a minimum cost of generation within the operating conditions, but also ensure frequency stability. In order to obtain this solution, the requirement of frequency stability is introduced as a new constraint of the power dispatch problem and is represented by the maximum frequency deviation limit. This new constraint is constructed as a nonlinear function of system inertia and the frequency regulation constant, since frequency deviation is highly sensitive to these factors. It is shown that the inclusion of this constraint causes the OPF to preferentially select higher inertia generators as necessary, to satisfy the frequency security requirement. A genetic algorithm is utilized as the optimization tool in this article. The IEEE RTS-79 test system is used to demonstrate efficacy of the proposed method.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • An Efficient Energy Management Approach for a Solar-Powered EV Battery
           Charging Facility to Support Distribution Grids
    • Authors: Viet Thang Tran;Md. Rabiul Islam;Kashem M. Muttaqi;Danny Sutanto;
      Pages: 6517 - 6526
      Abstract: The home photovoltaic (HPV) system integrated with energy storages can supply power to the distribution grid which may be reliable and free from HPV intermittency effects. However, this is always associated with the high cost of energy storages. On the other hand, the growth of electric vehicles (EVs) in the market has a potential to place the distribution grid in a high risk as the EV owners may charge the EV battery on demand which may cause an unexpected increase in the evening and power quality problems. This article proposes an efficient energy management approach for the HPV systems to power the electric vehicle battery (EVB) charging facility while utilizing the EVB as an energy storage system (ESS) that can mitigate the HPV impacts and allow the growth of HPV systems in power grids. This research is aimed for EVs that are compatible with the dc fast charging CHAdeMO standard. The operation strategy of the HPV-EVB charging system is designed in such a way that the EVB is charged efficiently either by the HPV or by the distribution grid. The proposed energy management strategy will help reduce the unexpected peak power demand, and can help in the implementation of the vehicle-to-grid (V2G) to improve the stability of the grid during peak load. In addition, the EVB can provide power to the critical loads in the home when there is a loss of power supply from the grid. In the proposed system, the HPV, the grid, and the EVB converters share a common dc bus. Both simulation and experimental results show that the proposed energy management of the HPV-EVB system can reduce the impacts of the high penetration of EVs and HPVs on power distribution grids and can effectively improve the self-consumption of the HPV systems.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Analysis and Design of Current-Fed Three-Phase-Isolated LCC-T Resonant
           Converter for Low-Voltage High-Current Applications
    • Authors: Venkata R. Vakacharla;Akshay Kumar Rathore;
      Pages: 6527 - 6537
      Abstract: A three-phase-isolated current-fed dc-dc converter with LCC-T resonant tank to achieve an efficient and compact design is proposed. Traditional dc-dc converters require an external parallel inductor to increase the transformer magnetizing current to realize soft switching under light-load conditions. The proposed LCC-T configuration eliminates this requirement and realizes light-load soft switching with reduced circulating current. In addition, the proposed topology maintains zero-voltage switching (ZVS) turn-ON of primary switches, ZVS turn-ON and zero-voltage-zero-current switching turn-OFF of secondary diodes for all load conditions. Steady-state operation, analysis, and design of the proposed converter are reported. Experimental results of 1-kW hardware prototype to verify the claims of the proposed analysis and design are presented.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • A System Emulator for AC Microgrid Testing
    • Authors: A. S. Vijay;Mukul C. Chandorkar;Suryanarayana Doolla;
      Pages: 6538 - 6547
      Abstract: The control algorithms proposed to improve load sharing, stability, and power quality in microgrids need rigorous testing. Real-time emulation is one of the proven approaches to provide realistic testing environments for the development of products and control algorithms. Typically, for microgrid system-level testing, individual component-level (source or load) emulators are employed: hardware test bed clusters. These use multiple converters, increasing control complexity and consuming space. In this article, we propose a flexible microgrid system emulator, based on a single converter for the testing of a complete microgrid, at any node selected by the user. This is unlike the case of emulators proposed in the literature till date, which use a large number of converters to emulate the system dynamics, wherein each converter is used to mimic the behavior of one particular component, such as a single source or a single load. The modeling and control aspects are discussed, and the accuracy of the model developed and the working of the emulator are established through simulations and experiments on a laboratory prototype, respectively, considering the case of a simple two-distributed-generator-based microgrid for various scenarios.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Modeling the Luminance Degradation of OLEDs Using Design of Experiments
    • Authors: Farah Salameh;Andrea Al Haddad;Antoine Picot;Laurent Canale;Georges Zissis;Marie Chabert;Pascal Maussion;
      Pages: 6548 - 6558
      Abstract: Modeling the lifespan of an organic light-emitting diode (OLED) is a complex task as it depends on different potentially interacting factors. As the literature on this subject is still scant, new parametric models for calculating the lifespan of the OLED are proposed in this article. The design of experiment (DoE) methodology is used for cost and accuracy reasons. Different lifespan models based on thermal and electrical experimental aging tests are proposed. As stress factors, current density, temperature, and their interactions, which are rarely taken into account in aging studies, are simultaneously involved. The analysis of the model parameters highlights the prevalence of temperature compared to current density on the luminance performance of OLEDs. Nonlinear models appear as the most accurate.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Invisibility and Readability of Temporally and Spatially
           Intensity-Modulated Metaimage for Information Hiding on Digital Signage
           Display System
    • Authors: Hiroshi Unno;Kazutake Uehira;
      Pages: 6559 - 6566
      Abstract: This paper describes a display technique that enables us to invisibly embed a metaimage into a color component of a displayed cover image by using a temporally, spatially, color-intensity-modulated metaimage and to extract it. We first examined invisibility in terms of color components for a temporally and spatially intensity-modulated metaimage in a displayed cover image. The results obtained from these experiments revealed that the invisibility with which the metaimage was embedded in the blue color component was much higher than that of the red and green components. Our experiments also revealed that the red and green components could not be used for a color component in which the metaimage was embedded. We also proposed and evaluated a new technique of improving the readability of an invisibly embedded metaimage in a displayed cover image captured with a video camera. The proposed technique uses two methods. A proposed method of calculating an estimated grayscale metaimage enabled us to obtain a value for the binarizing threshold from its histogram by using the correlation between color components in which the metaimage was either embedded or not embedded. A proposed method of calculating an estimated binary metaimage could drastically reduce noise caused by the cover image by using the obtained value of the binary threshold and size feature parameters of the embedded metaimage. The readability of the metaimage was drastically improved by using these methods.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Power Estimation of a Current Supplied DBD Considering the Transformer
           Parasitic Elements
    • Authors: Vanesa Rueda;Arnold Wiesner;Rafael Diez;Hubert Piquet;
      Pages: 6567 - 6575
      Abstract: Power estimation of a DBD device supplied by a current source converter is studied in this article, pointing out the prominent contribution of the transformer parasitic elements. The impact of the stray capacitance and magnetizing inductance is stated and an iterative method that estimates the electrical power and DBD waveforms is presented. Results show that the magnetizing inductance can enhance the electrical power without changing the current ratings of the converter and that the stray capacitance must be minimized. Moreover, the experimental results reveal the need for a better DBD model to properly estimate the power. In consequence, an improved model is proposed and validated using a DBD excimer lamp in a wide range of electrical operating conditions.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Advancing Technology in Upgrading or Replacing Vintage Low-Voltage Motor
           Control Centers
    • Authors: David B. Durocher;Matthew R. Hussey;
      Pages: 6576 - 6584
      Abstract: Low-voltage motor control centers (LV MCCs) are universally applied in the process industries. These electrical assemblies are perhaps one of the most dynamic in the industry, ever-changing as the low-voltage motor loads are constantly added and modified in response to necessary process revisions and upgrades. As existing LV MCCs approach 40-50 years in age, industry users are challenged with a decision either to replace vintage motor control centers (MCCs) at their end of life or consider to upgrade existing assemblies. This article will discuss the upgrade versus replace alternatives, addressing Underwriter's Laboratories 845 North American industry standard requirements and how this affects the design, installation, and maintenance of both upgraded and new MCCs. Application issues including considering the cost of replacing load cables versus the reuse of existing cables, high-resistant ground systems and opportunities for process improvements, and network communications that leverage the latest technology will be discussed. Finally, a case study comparing the replacement of an existing MCC versus a field upgrade based on changing out all exiting starter and feeder circuit breaker units including an estimate of the total installed cost for both alternatives for this application will be reviewed.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Factors Determining the Effectiveness of a Wind Turbine Generator
           Lightning Protection System
    • Authors: Raghavender Goud Deshagoni;Tony Auditore;Ramesh Rayudu;Ciaran P. Moore;
      Pages: 6585 - 6592
      Abstract: As a result of the growing supply and demand for wind power, wind turbine generators are increasingly being installed at suboptimal sites that have high soil resistivity and high incidence of lightning strikes. This means that lightning protection systems for wind turbines are becoming a critical component of wind farm design. Not only do effective lightning protection systems ensure the safety of the physical wind turbine structure and human operators, they also protect the electrical and control systems installed inside wind turbine generators and safeguard the lives of human operators. This paper presents a framework to assess the effectiveness of wind turbine lightning protection systems at the wind farm design phase. Performing the analysis at this early stage reduces lightning-induced downtime, which leads to increased energy yield. Our results show that the grounding system plays a critical role in the wind turbine lightning protection system. For this reason, we also analyze various influential parameters of a grounding system design. We present results from full-wave electromagnetic simulations of the complete wind turbine grounding system, including the foundation.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Workers at Risk of Fatal and Nonfatal Electrical Injuries
    • Authors: Tammy Gammon;Derek Vigstol;Richard Campbell;
      Pages: 6593 - 6602
      Abstract: The electrical safety community has made great strides in reducing electrical injuries to electrical workers through elimination, mitigation, administrative controls, worker training, and personal protective equipment. However, a large percentage of fatal and nonfatal electrical injuries occur to nonelectrical workers. This article uses Bureau of Labor Statistics data and Occupational Safety and Health Administration records to identify workers and types of work vulnerable to electrical injury. Odds of electrical or occupational injury or fatality are included for risk perspective. To decrease the likelihood of electrical injuries in at-risk workers, electrical safety programs must effectively target and reach at-risk workers. Appropriate training and ways to reach nonelectrical workers vulnerable to electrical injury are discussed.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Electrical Safety Considerations in Large-Scale Electric Vehicle Charging
    • Authors: Bo Wang;Payman Dehghanian;Shiyuan Wang;Massimo Mitolo;
      Pages: 6603 - 6612
      Abstract: Several safety regulations, particularly concerning the charging of electric vehicles (EVs) are developed to ensure electric safety and prevent hazardous accidents, in which safety requirements for the EV supply equipment (EVSE) and the EV battery are two main driving factors. At present, quantitative assessment of electrical safety considering the operation conditions of large-scale EV charging stations (EVCSs) has still remained a challenge. Driven by the hierarchy of hazard control mechanisms, this article proposes a holistic approach to evaluate the electrical safety of the large-scale EVCSs when coupled to renewable power generation. Our approach mainly focuses on several topics on the operational safety of EVCS primarily concerning: 1) the facility degradation which could potentially result in a compromised EVSE reliability performance and EVCS protection failure; 2) the cyberattack challenges when the smart charging and the communication between EVCSs and electric utilities are enabled; and 3) the potential mismatch between the renewable output and EVCS demand, which could trigger the system stability challenges during normal operation and inability to supply the critical EV loads during outages. The proposed framework will provide informative guidelines to the EVCS operators for continuous monitoring and effective management of the day-to-day EVCS operation.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Real-Time Detection of Interharmonics and Harmonics of AC Electric Arc
           Furnaces on GPU Framework
    • Authors: Eda Uz-Logoglu;Ozgul Salor;Muammer Ermis;
      Pages: 6613 - 6623
      Abstract: In this paper, a method based on the multiple synchronous reference frame analysis is recommended and implemented to detect time-varying harmonics and interharmonics of rapidly fluctuating asymmetrical industrial loads. The experimental work has been carried out on a typical three-phase alternating current arc furnace installation. In the recommended method, the reference frame is rotated in both directions at speeds corresponding to the positive and negative sequences of all harmonics and all interharmonics 5 Hz apart. To extract the direct current components of the transformed d-q quantities, a low-pass filter is employed. In order to keep the delay of the filter at zero frequency less than a few ms, Kalman estimation technique has been used. Back transformation is then applied for each harmonic and interharmonic component to obtain their positive- and negative-sequences of the associated harmonic and interharmonic in the actual line current waveforms. Parallel computing technique has been applied for the real-time detection of both the phase and the amplitude of all harmonics and interharmonics. This is achieved on NVDIA Jetson TX1 graphics processing unit framework for a sample industrial plant. The developed system is shown to be useful for fast and accurate generation of reference signals for the controllers of the advanced technology power conditioning systems which successfully compensates interharmonics, harmonics, and flicker of the rapidly fluctuating nonlinear industrial loads.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • EAF Arc Stability Through the Use of UPFCs
    • Authors: E. A. Cano-Plata;A. J. Ustariz-Farfán;C. Arango-Lemoine;
      Pages: 6624 - 6632
      Abstract: The use of a unified power flow controller (UPFC) to improve the power transfer in an EAF is investigated. The implemented equipment used techniques of hardware-in-the-loop to determine the required specific characteristics of the UPFC to improve the stability of the arc. The arc is mainly responsible for the conversion of electromagnetic power into thermal power and heat transfer. The stability studies of power networks help in improving the stability of the arc. These are the topics covered in this paper. This research also shows how it is possible to achieve an increment of the stability of the arc with the enhancement of the power quality between the main transformer and the distribution system through the decrease of the THDI, unbalance, and flicker.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Influence of Solid Rotor Steel on Dynamic Response and Losses of
           Turbogenerator With Loss of Excitation
    • Authors: Guorui Xu;Chaolong Luo;Yang Zhan;Haisen Zhao;
      Pages: 6633 - 6642
      Abstract: The rotor of turbogenerator is made of solid steel, instead of laminated steel, for its high-speed rotation. The asynchronous torque resulting from the eddy current in the rotor core plays an important role in the asynchronous operation of turbogenerator after loss of excitation. On the other hand, the rotor loss and temperature rise restrict the operation of turbogenerator. The selection of solid steel is therefore a key factor that affects the operation limit and should be carefully considered in the design of turbogenerators. For a turbogenerator with the rotor core made of different solid steel, this paper presents time-stepping finite element calculation of the asynchronous performances and the experimental validation. The influences of different rotor solid steel on the dynamics, saturation, asynchronous operation ability, and rotor loss of turbogenerator with the loss of field are studied. The losses in different areas of rotor are calculated and compared. The results provide steel manufacturers and generator designers with the theoretic basis for improvement of the asynchronous operating ability of turbogenerator.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Evaluation of Series and Parallel Hybrid Filters Applied to Hot Strip
           Mills With Cycloconverters
    • Authors: Hélio M. A. Antunes;Igor A. Pires;Sidelmo M. Silva;
      Pages: 6643 - 6651
      Abstract: This article presents two hybrid filter topologies applied to a hot strip mill electrical system with cycloconverters, to evaluate the harmonic compensation and damping of harmonic resonance. In addition, an evaluation of the performance of hybrid filters in reducing the current rating of the passive filter is also presented. The most relevant waveforms of the system and its harmonic spectrum are analyzed, to assess the performance of each filtering structure in improving the power quality. The results obtained through digital simulation show that a series hybrid filter provides harmonic damping and allows enhancing the harmonic compensation characteristics of the passive filtering system, using an active filter of lower rated power compared to a parallel hybrid filter. However, the series hybrid filter does not present good filtering characteristics in the high-frequency range, that can be performed by a parallel hybrid filter with a higher rating.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Overcurrent Protection in Electric Arc Furnaces
    • Authors: S. Arias-Guzman;A. J. Ustariz-Farfán;E. A. Cano-Plata;
      Pages: 6652 - 6659
      Abstract: This article proposes a new adaptive protection setting methodology for steel manufacturers, aiming to reduce miscoordination between main feeders and current consumptions due to fault clearance or high load disconnection. By detecting abrupt changes in current consumption, the computation of different protection settings may be achieved. The application of this methodology is performed through the assessment of a steel manufacturer who sustained an arc blast of one of their protection cells, and a description of the way in which the proposal permits avoidance of such catastrophic conditions.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Modulation Effects in an Inverter Fed Nine-Phase Induction Motor Drive
    • Authors: Rodrigo Rodrigues Bastos;Tamires Santos de Souza;Braz de Jesus Cardoso Filho;
      Pages: 6660 - 6669
      Abstract: Using electric motors with a number of phases greater than three present some advantages over conventional three-phase machines: higher reliability, reduced power per phase, increased torque density, and reduced torque pulsations. As the number of phases increases, the complexity of the modulation also increases due to a larger number of switching vectors and harmonic planes. A nine-phase inverter implies 512 switching vectors in each one of its four harmonic planes. In this article, a modulation technique for a nine-phase inverter based on a subset of the voltage vectors that yields a reduced number of on/off transitions in a switching period is shown. The resulting harmonics and their effects in multiphase machines are analyzed. Third harmonic injection is considered from the perspective of both torque improvement and dc bus voltage utilization. Simulation, finite element, and experimental results are presented to support the authors' conclusions.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Effects of Light Spectrum on Luminance Measurements in Underground Coal
    • Authors: Max Juarez Martell;John J. Sammarco;Brendan D. Macdonald;
      Pages: 6670 - 6677
      Abstract: Lighting regulations for luminance in U.S. coal mines are verified in the field by using a luminance photometer calibrated to the Standard Illuminant A light source. Significant measurement errors can exist when measuring light sources that are dissimilar to light sources used to calibrate the photometer. This article quantifies the measurement errors when measuring these dissimilar light sources commonly used in U.S. underground coal mines—a light-emitting diode (LED), a compact fluorescent light (CFL) with a clear cover, a CFL with an amber cover, and a tungsten halogen. The impact of photometer quality was also evaluated. Three different luminance measuring instruments of high, medium, and low quality were compared—a PR-650, LS-100, and PMEX, respectively. The PMEX was under evaluation for measuring luminance compliance in U.S. underground coal mines. The PR-650 was used as the referent to which the other photometers were compared. The PMEX error ranged from −17.0% to −26.5% with the highest error for the amber CFL. The LS-100 closely matched the luminance measurement for the LED and halogen; however, it had a percent error of −10.4% for the amber CFL. After the initial experiment, Mine Safety and Health Administration (MSHA) made improvements to the PMEX resulting in the PMEX-MSHA. The experiment was replicated using the new photometer and the newer PR-670. After repeating the experiment, the measurement errors ranged from −16% to −19% for the PMEX-MSHA, thus indicating an improvement over the PMEX. These results show that the spectral content of a light source and the photometer quality can greatly impact the accuracy of luminance measurement.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • Selection and Tests of Innovative Variable-Speed Motor–Compressor
           Solutions for a 55-MW Full Electric Offshore Platform Maximizing
           Availability and Efficiency With Better Environmental Impact
    • Authors: Lionel Durantay;Thomas Alban;Sami Siala;Antoine Billaud;
      Pages: 6678 - 6689
      Abstract: A new concept of an electric offshore platform, sized to 55 MW, which is powered from the shore via a 161-km subsea cable, is currently being commissioned in the North Sea. Only electrical motors drive the rotating equipment such as the compressors and the pumps. The first part of this paper overviews the selected global architecture of the electric compression based on three variable-speed direct drive solutions for gas exports in term of flexibility, operability, efficiency, compactness of integration, and environmental impact. The second part focuses on the motor-compressor technology including the 250-Hz voltage-source-inverter drive with a compact filter and robust control, the gearless rotating equipment combining a totally enclosed water-air cooled (TEWAC) induction motor and a compressor on active magnetic bearings operating up to 7 MW at 14 500 r/min. The gas string test results are presented validating the system performance and compactness. The conclusion is dedicated to the next generation of mature solutions using standalone and integrated topside or subsea machine improving the system reliability and operability.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • IEEE Open Access Publishing
    • Pages: 6690 - 6691
      Abstract: Advertisement, IEEE.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
  • IEEE Open Access Publishing
    • Pages: 6692 - 6692
      Abstract: Advertisement, IEEE.
      PubDate: Nov.-Dec. 2019
      Issue No: Vol. 55, No. 6 (2019)
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Tel: +00 44 (0)131 4513762
Fax: +00 44 (0)131 4513327
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