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Energy, Electrical and Power Engineering: 3rd Edition

A special issue of Energies (ISSN 1996-1073). This special issue belongs to the section "F: Electrical Engineering".

Deadline for manuscript submissions: 20 February 2025 | Viewed by 8649

Special Issue Editors

Prof. Dr. Wenping Cao

E-Mail Website
Guest Editor
School of Engineering and Applied Science, Aston University, Birmingham B4 7ET, UK
Interests: electrical machines and drives; power electronics; power systems; wind power; electric vehicles
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Cungang Hu

E-Mail Website
Guest Editor
School of Electrical Engineering and Automation, Anhui University, Hefei 23061, China
Interests: electric machines and drives; power electronics; power system analysis; new and renewable energy; big data analytics
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Xiaoyan Huang

E-Mail Website
Guest Editor
Department of Electrical Machine, Zhejiang University, Hangzhou 310024, China
Interests: permanent magnet motor; high speed train traction system; high efficiency motor drive system for EV; fault tolerant motor drives for aerospace; PMSM motor intelligent control
Special Issues, Collections and Topics in MDPI journals
Dr. Pinjia Zhang

E-Mail Website
Guest Editor
Department of Electrical Engineering, Tsinghua University, Beijing 10084, China
Interests: renewable energy; micro grid and energy storage; monitoring
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Energy and power are playing an increasingly pivotal role in our modern life and are transforming the way we utilize energy and the way we live. This special issue will bring together the latest innovations and knowledge in energy and power engineering such as new and renewable energy, power electronics and electric motor drives, distributed generation and multi-energy systems, data analytics, and artificial intelligence. You are cordially invited to contribute to the Special Issue and present your new work.

Topics of Interest include but are not limited to:

  • Analogue and Digital Signal Processing
  • Artificial Intelligence
  • Big Data and Data Processing
  • Bioenergy and Utilization
  • Communication Systems
  • Control Theory and Optimisation
  • Diagnosis and Sensing Systems
  • Distributed Generation
  • Electrical Generators
  • Electrical Motor Drives
  • Electromagnetic and Applied Superconductivity
  • Electronics, Information and Control Systems
  • Energy Market and Power System Economics
  • Energy Storage
  • Engineering Materials and Process
  • Fuel Cells and Applications
  • Industrial Process Control and Automation
  • Intelligent control systems
  • Mechatronics and Robotics
  • Modeling, Simulation, and Analysis
  • Nuclear Energy
  • Power Electronic Converters
  • Power Generation and Sustainable Environment
  • Power Quality and Electromagnetic Compatibility
  • Power Planning and Scheduling
  • Power Semiconductors
  • Predictive Control
  • Protection, Operation, and Control
  • Real-Time Control
  • Reliability and Security
  • Renewable Energy
  • Sensors, Instruments, and Measuring Technologies
  • Smart Cities and Smart Grids
  • Solar energy and photovoltaics
  • Transmission and Distribution Systems
  • Wind energy

Thank you very much for your participation!

Prof. Dr. Wenping Cao
Prof. Dr. Cungang Hu
Prof. Dr. Xiaoyan Huang
Dr. Pinjia Zhang
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Energies is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • power converters
  • motor drives
  • electrified vehicles
  • wind power generation
  • measurement techniques

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Related Special Issue

Published Papers (15 papers)

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Research

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29 pages, 9515 KiB  
Article
Analysis of Gas-Steam CHP Plants Without and with Heat Accumulator and HTGR Reactor
by Ryszard Bartnik, Anna Hnydiuk-Stefan and Zbigniew Buryn
Energies 2024, 17(22), 5702; https://doi.org/10.3390/en17225702 - 14 Nov 2024
Viewed by 387
Abstract
This study analyzes the thermodynamic and economic viability of modified high-temperature gas-cooled reactor (HTGR) gas-steam combined heat and power (CHP) systems compared to conventional CHP plants. The research addresses the critical need for efficient and sustainable energy production methods. Using comprehensive thermodynamic modeling [...] Read more.
This study analyzes the thermodynamic and economic viability of modified high-temperature gas-cooled reactor (HTGR) gas-steam combined heat and power (CHP) systems compared to conventional CHP plants. The research addresses the critical need for efficient and sustainable energy production methods. Using comprehensive thermodynamic modeling and economic analysis, the study evaluates system performance under various operating conditions. Key findings reveal that modified CHP plants with HTGR and turboexpanders (TEs) demonstrate significantly higher efficiency and lower heat generation costs compared to conventional gas turbine (GT) CHP plants, despite higher initial capital investments. The modified systems achieve electricity generation efficiencies up to 48%, surpassing traditional nuclear power plants. The absence of CO2 emissions and lower fuel costs in HTGR systems contribute to their economic advantage. This research provides novel insights into the potential of HTGR technology in CHP applications, offering a promising solution for future energy systems. The study’s originality lies in its comprehensive comparison of conventional and modified CHP systems, considering both thermodynamic and economic aspects, which has not been extensively explored in existing literature. Full article
(This article belongs to the Special Issue Energy, Electrical and Power Engineering: 3rd Edition)
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16 pages, 20540 KiB  
Article
Evaluation of an Infinite-Level Inverter Operation Powered by a DC–DC Converter in Open and Closed Loop
by Nataly Gabriela Valencia Pavón, Alexander Aguila Téllez, Javier Rojas Urbano, Víctor Taramuel Obando and Edwin Guanga
Energies 2024, 17(22), 5593; https://doi.org/10.3390/en17225593 - 8 Nov 2024
Viewed by 346
Abstract
This paper evaluates the open- and closed-loop DC–DC converter operation within a DC coupling multilevel inverter architecture to obtain an infinite-level stepped sinusoidal voltage. Adding a cascade controller to the DC–DC converter should reduce the settling time and increase the number of levels [...] Read more.
This paper evaluates the open- and closed-loop DC–DC converter operation within a DC coupling multilevel inverter architecture to obtain an infinite-level stepped sinusoidal voltage. Adding a cascade controller to the DC–DC converter should reduce the settling time and increase the number of levels in the output voltage waveform; it could decrease the speed error and phase shift concerning the sinusoidal reference signal. The proposed methodology consists of implementing an experimental multilevel inverter with DC coupling through a single-phase bridge inverter energized from a BUCK converter. Trigger signals for the two converters are obtained from a control circuit based in an ATMEGA644P microcontroller to explore its capabilities in power electronics applications. A digital controller is also implemented to evaluate the operation of the BUCK converter in open and closed loop and observe its influence in the stepped sinusoidal output voltage. The evaluation is performed to energize a resistive load with common output voltage in multilevel inverters, i.e., 3, 5, 7, 11, and infinity levels. Results show that during the design stage, fast dynamic elements, like the storage capacitor, can be used to obtain a minimum THD because the settling time is sufficiently fast, the speed error remains small, and there is no need for a controller. A digital controller requires processing time, and although in theory it can reduce the settling time to a minimum, the processor introduces latency in the control signals generation, producing the opposite effect. Controller complexity of the digital controller must be considered because it increases processing time and influences the efficiency of the closed-loop operation. Full article
(This article belongs to the Special Issue Energy, Electrical and Power Engineering: 3rd Edition)
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17 pages, 5813 KiB  
Article
Research on Voltage Prediction Using LSTM Neural Networks and Dynamic Voltage Restorers Based on Novel Sliding Mode Variable Structure Control
by Jian Xue, Jingran Ma, Xingyi Ma, Lei Zhang and Jing Bai
Energies 2024, 17(22), 5528; https://doi.org/10.3390/en17225528 - 5 Nov 2024
Viewed by 426
Abstract
To address the issue of uncertainty in the occurrence time of voltage sags in power grids, which affects power quality, a voltage state prediction method based on LSTM neural networks is proposed for predicting voltage states. For the problem of quickly and accurately [...] Read more.
To address the issue of uncertainty in the occurrence time of voltage sags in power grids, which affects power quality, a voltage state prediction method based on LSTM neural networks is proposed for predicting voltage states. For the problem of quickly and accurately compensating for voltage sags, a DVR system based on a new approach law of sliding mode variable structure control is proposed, which significantly reduces chattering, improves response speed, and enhances the robustness of the system. The stability of the system is proven based on Lyapunov stability theory. Simulation experiments are conducted to analyze the voltage state prediction effect based on the LSTM neural network and the compensation effect of the novel reaching law of sliding mode variable structure control under different levels of voltage sag, validating the effectiveness and correctness of the proposed solution. Full article
(This article belongs to the Special Issue Energy, Electrical and Power Engineering: 3rd Edition)
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19 pages, 784 KiB  
Article
Electricity Bill Savings from Reduced Household Energy Consumption in Apartment Complexes
by Young Mo Chung, Beom Jin Chung and Dong Sik Kim
Energies 2024, 17(21), 5488; https://doi.org/10.3390/en17215488 - 2 Nov 2024
Viewed by 627
Abstract
Apartments account for 64.6% of all housing units in the Republic of Korea, and most of them receive electricity under a contract, which includes a progressive rate plan. Recently, due to the electrification of energy used in homes and the growing adoption of [...] Read more.
Apartments account for 64.6% of all housing units in the Republic of Korea, and most of them receive electricity under a contract, which includes a progressive rate plan. Recently, due to the electrification of energy used in homes and the growing adoption of electric vehicles, electricity consumption in apartment complexes has been gradually increasing. Given the characteristics of the progressive rate system, an increase in electricity usage results in a significant higher rise in electricity bills. Thus, an effective alternative is required to reduce electricity bills for each household. In this paper, the savings in electricity bills achieved by reducing household electricity usage are analyzed from both apartment complex and individual household perspectives, using metering data from 13,332 households. When households are sorted by the amount of savings in descending order, the resulting values are found to follow a negative exponential curve. This indicates that the benefits from reducing electricity usage in households with higher saving are significantly larger compared to other ones. We analyzed bill savings when electricity usage reductions were selectively applied to the top 10%, 20%, and 30% of households with the largest savings. From the results, it is found that the largest savings in electricity bills for households are achieved when usage reductions are applied to the top 10% of households. It is expected that this amount of savings would encourage these households to reduce their electricity consumption. Additionally, it is found that the savings for apartment complexes and the total savings for selected households are not the same, resulting in changes in the bills for households that do not reduce their usage. From the results, it was observed that when the usage reduction of selected households is small or the proportion of households reducing usage is low, the common area charges for non-reducing households tend to increase, leading to higher electricity bills. On the contrary, when the usage reduction of selected households is large or the proportion of households reducing usage is high, the common area charges for non-reducing households tend to decrease, resulting in lower electricity bills. Full article
(This article belongs to the Special Issue Energy, Electrical and Power Engineering: 3rd Edition)
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17 pages, 1709 KiB  
Article
Point of Common Connection Voltage Modulated Direct Power Control with Disturbance Observer to Increase in Renewable Energy Acceptance in Power System
by Yong Woo Jeong and Woo Young Choi
Energies 2024, 17(21), 5319; https://doi.org/10.3390/en17215319 - 25 Oct 2024
Viewed by 508
Abstract
In this paper, we present a disturbance observer-based point of common connection voltage-modulated direct power control (PCCVM-DPC) system, which increases the robustness of the PCCVM-DPC system. First, the mathematical analysis of the disturbances for the step-up transformer’s nonlinearity, the grid voltage harmonics, and [...] Read more.
In this paper, we present a disturbance observer-based point of common connection voltage-modulated direct power control (PCCVM-DPC) system, which increases the robustness of the PCCVM-DPC system. First, the mathematical analysis of the disturbances for the step-up transformer’s nonlinearity, the grid voltage harmonics, and the parameter uncertainties is presented. By analyzing the disturbance terms of the PCCVM-DPC system, we present the disturbance observer (DOB) for the PCCVM-DPC system. To assess the efficacy of our approach, we perform comparative studies of the PCCVM-DPC without DOB and PCCVM-DPC with DOB by constructing the simulation environment based on the commercial step-up transformer and ESS inverter datasheet. We have validated that the active and reactive power control performance of the PCCVM-DPC with DOB outperforms the PCCVM-DPC without DOB from the observation that the current total harmonic distortion reduced by more than 40% compared to the PCCVM-DPC without the DOB. Full article
(This article belongs to the Special Issue Energy, Electrical and Power Engineering: 3rd Edition)
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26 pages, 5739 KiB  
Article
Active Battery Voltage Equalization Based on Chain-Loop Comparison Strategy
by Kuo-Ing Hwu, Yuan-Hua Lin and Jenn-Jong Shieh
Energies 2024, 17(20), 5156; https://doi.org/10.3390/en17205156 - 16 Oct 2024
Viewed by 639
Abstract
This paper describes active battery balancing based on a bidirectional buck converter, a flyback converter, and battery cells by using the proposed chain-loop comparison strategy. The role of the bidirectional buck converter is to charge/discharge the battery pack. During the charging period, the [...] Read more.
This paper describes active battery balancing based on a bidirectional buck converter, a flyback converter, and battery cells by using the proposed chain-loop comparison strategy. The role of the bidirectional buck converter is to charge/discharge the battery pack. During the charging period, the converter is in buck mode, and its output is controlled by constant current/voltage; during the discharging period, the converter is in boost mode, and its output is controlled by constant voltage. The role of the flyback converter is voltage equalization of the battery pack, and its output is controlled by constant current. A chain-loop comparison strategy is used to control battery voltage equalization. In this work, three equalization modes, namely, charging balance, discharging balance, and static balance, were considered. The voltage difference between the maximum and minimum is 0.007 V after a balancing time of 19.75 min, 0.005 V after a balancing time of 24 min, and 0.007 V after a balancing time of 20 min for charging balance, discharging balance, and static balance, respectively. Full article
(This article belongs to the Special Issue Energy, Electrical and Power Engineering: 3rd Edition)
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15 pages, 4630 KiB  
Article
Loss and Thermal Analysis of a High-Power-Density Permanent Magnet Starter/Generator
by Xiaojun Ren, Zhikai Chen, Rui Du and Ming Feng
Energies 2024, 17(20), 5049; https://doi.org/10.3390/en17205049 - 11 Oct 2024
Viewed by 671
Abstract
Reducing heat and improving the overall operation stability of the motor play a key role in the design of a starting engine. This paper focuses on the loss and thermal analysis of a permanent magnet (PM) brushless machine used in starter generators. The [...] Read more.
Reducing heat and improving the overall operation stability of the motor play a key role in the design of a starting engine. This paper focuses on the loss and thermal analysis of a permanent magnet (PM) brushless machine used in starter generators. The loss of the starter generator was calculated through a combination of theoretical analysis and the finite element method. A thermal analysis model was established based on the division of the fluid domain, boundary grid, heat source setting, and so on. The temperature fields of the whole motor and the main components were calculated and analyzed. The main factors affecting the air cooling effect were analyzed, including air flow rate, air temperature, and motor speed. A prototype experimental platform of the SG motor was built. The efficiency and temperature rise in the motor were tested. The temperature values were compared with the calculated values. The experimental results show that the performance of the motor is excellent, and the error between the temperature and the design calculation is less than 10% under each load torque. The accuracy of the thermal analysis method is verified. The correctness of the motor transient model was also confirmed through a temperature rise experiment under rated conditions, providing a research basis for improving operation efficiency. Full article
(This article belongs to the Special Issue Energy, Electrical and Power Engineering: 3rd Edition)
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20 pages, 3409 KiB  
Article
Comparison of Optimal SASS (Sparsity-Assisted Signal Smoothing) and Linear Time-Invariant Filtering Techniques Dedicated to 200 MW Generating Unit Signal Denoising
by Marian Łukaniszyn, Michał Lewandowski and Łukasz Majka
Energies 2024, 17(19), 4976; https://doi.org/10.3390/en17194976 - 4 Oct 2024
Viewed by 670
Abstract
Performing reliable calculations of power system dynamics requires accurate models of generating units. To be able to determine the parameters of the models with the required precision, a well-defined testing procedure is used to record various unit transient signals. Unfortunately, the recorded signals [...] Read more.
Performing reliable calculations of power system dynamics requires accurate models of generating units. To be able to determine the parameters of the models with the required precision, a well-defined testing procedure is used to record various unit transient signals. Unfortunately, the recorded signals usually contain discontinuities, which complicates the removal of the existing harmonic interferences and noise. A set of four transient signals recorded during typical disturbance tests of a 200 MW power-generating unit was used as both training and research material for the signal denoising/interference removal methods compared in the paper. A systematic analysis of the measured transient signals was conducted, leading to the creation of a coherent mathematical model of the signals. Next, a method for denoising power-generating unit transient signals is proposed. The method is based on Sparsity-Assisted Signal Smoothing (SASS) combined with optimization algorithms (simulated annealing and Nelder-Mead simplex) and is called an optimal SASS method. The proposed optimal SASS method is compared to its direct Linear Time-Invariant (LTI) competitors, such as low-pass and notch filters. The LTI methods are based on the same filter types (Butterworth filters) and zero-phase filtering principle as the SASS method. A set of specially generated test signals (based on a developed mathematical model of the signals) is used for the performance evaluation of all presented filtering methods. Finally, it is concluded that—for the considered class of signals—the optimal SASS method might be a valuable noise removal technique. Full article
(This article belongs to the Special Issue Energy, Electrical and Power Engineering: 3rd Edition)
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22 pages, 2716 KiB  
Article
Intelligent Identification Method of Low Voltage AC Series Arc Fault Based on Using Residual Model and Rime Optimization Algorithm
by Xiao He, Takahiro Kawaguchi and Seiji Hashimoto
Energies 2024, 17(18), 4675; https://doi.org/10.3390/en17184675 - 20 Sep 2024
Viewed by 560
Abstract
Aiming at the problem of accurate AC series arc fault detection, this paper proposes a low voltage AC series arc fault intelligent detection model based on deep learning. According to the GB/T 31143—2014 standard, an experimental platform was established. This system comprises a [...] Read more.
Aiming at the problem of accurate AC series arc fault detection, this paper proposes a low voltage AC series arc fault intelligent detection model based on deep learning. According to the GB/T 31143—2014 standard, an experimental platform was established. This system comprises a lower computer (slave computer) and an upper computer (master computer). It facilitates the acquisition of experimental data and the detection of arc faults during the data acquisition process. Based on a one-dimensional Convolutional Neural Network (CNN), Residual model (Res) and RIME optimization algorithm (RIME) are introduced to optimize the CNN. The current signals collected using high-frequency current, low-frequency coupled current, and high-frequency coupled current are used to construct an arc fault feature set for training of the necessary detection model. The experimental results indicate that the RIME optimization algorithm delivers the best performance when optimizing a one-dimensional CNN detection model with an introduced Res. This model achieves a detection accuracy of 99.42% ± 0.13% and a kappa coefficient of 95.69% ± 0.96%. For collection methods, high-frequency coupled current signals are identified as the optimal choice for detecting low-voltage AC series arc faults. Regarding feature selection, random forest-based feature importance ranking proves to be the most effective method. Full article
(This article belongs to the Special Issue Energy, Electrical and Power Engineering: 3rd Edition)
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19 pages, 6160 KiB  
Article
Study on the Evolutionary Process and Balancing Mechanism of Net Load in Renewable Energy Power Systems
by Sile Hu, Jiaqiang Yang, Yu Guo, Yue Bi and Jianan Nan
Energies 2024, 17(18), 4654; https://doi.org/10.3390/en17184654 - 18 Sep 2024
Viewed by 717
Abstract
With the rapid development of renewable energy sources such as wind and solar, the net load characteristics of power systems have undergone fundamental changes. This paper defines quantitative analysis indicators for net load characteristics and examines how these characteristics evolve as the proportion [...] Read more.
With the rapid development of renewable energy sources such as wind and solar, the net load characteristics of power systems have undergone fundamental changes. This paper defines quantitative analysis indicators for net load characteristics and examines how these characteristics evolve as the proportion of wind and solar energy increases. By identifying inflection points in the system’s adjustment capabilities, we categorize power systems into low, medium, and high renewable energy penetration. We then establish adjustment models that incorporate traditional coal power, hydropower, natural gas generation, adjustable loads, system interconnections, pumped-storage hydroelectricity, and new energy storage technologies. A genetic algorithm is employed to optimize and balance the net load curves under varying renewable energy proportions, analyzing the mechanism behind net load balance. A case study, based on real operational data from 2023 for a provincial power grid in western China, which is rich in renewable resources, conducts a quantitative analysis of the system’s adjustment capability inflection point and net load balancing strategies. The results demonstrate that the proposed method effectively captures the evolution of the system’s net load and reveals the mechanisms of net load balancing under different renewable energy penetration levels. Full article
(This article belongs to the Special Issue Energy, Electrical and Power Engineering: 3rd Edition)
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14 pages, 3628 KiB  
Article
Investigation of the Arc Characteristics in a Nozzle with C4F7N/CO2 Mixtures
by Wen Wang, Xianglian Yan, Xiaolong Li, Dongyu Guo and Zhenxin Geng
Energies 2024, 17(18), 4593; https://doi.org/10.3390/en17184593 - 13 Sep 2024
Viewed by 425
Abstract
C4F7N is considered the most promising alternative to SF6 due to its higher liquefaction temperature, and it is generally mixed with buffering gases such as CO2 in engineering applications. This paper establishes a two-dimensional axisymmetric nozzle arc [...] Read more.
C4F7N is considered the most promising alternative to SF6 due to its higher liquefaction temperature, and it is generally mixed with buffering gases such as CO2 in engineering applications. This paper establishes a two-dimensional axisymmetric nozzle arc model based on magnetohydrodynamics, calculating the nozzle arc for air, SF6, and C4F7N/CO2 mixtures. The simulation model’s accuracy is validated by comparing the calculation results for air with experimental data. This study focuses on comparing and analysing the temperature distribution, arc voltage, and energy balance characteristics of the nozzle arcs for SF6 and C4F7N/CO2 mixtures. By comparing the physical properties of the two gases, the differences in their arc characteristics are explained. Finally, the influence of different C4F7N concentrations on the arc characteristics of the mixed gas is compared. The results show that the arc voltage of the C4F7N/CO2 mixtures is higher than that of the other two gases and increases asymptotically with the decrease in current. Among the three gases, the main form of arc energy dissipation is axial thermal convection, and both radial heat transfer and axial thermal convection are more significant in the C4F7N/CO2 mixtures, resulting in the lowest arc temperature, which is more conducive to arc extinguishing. This study provides an in-depth explanation of the differences in arc morphology and temperature between SF6 and C4F7N mixed gases by comparing their ρCp and ρh. The findings offer theoretical support for the design and optimisation of new environmentally friendly circuit breakers. Full article
(This article belongs to the Special Issue Energy, Electrical and Power Engineering: 3rd Edition)
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13 pages, 4189 KiB  
Article
Electromagnetic and Mechanical Stress Analysis of a 5 MW High-Pole Non-Overlap Winding Wound-Rotor Synchronous Wind Generator
by Karen S. Garner and Udochukwu B. Akuru
Energies 2024, 17(18), 4585; https://doi.org/10.3390/en17184585 - 12 Sep 2024
Viewed by 855
Abstract
Utilizing non-overlap windings has emerged as a favourable choice for minimizing electrical machine manufacturing costs, among other benefits. Nevertheless, it is widely acknowledged that these windings exhibit a notable level of harmonic contents in the resultant magnetomotive force, which can detrimentally impact machine [...] Read more.
Utilizing non-overlap windings has emerged as a favourable choice for minimizing electrical machine manufacturing costs, among other benefits. Nevertheless, it is widely acknowledged that these windings exhibit a notable level of harmonic contents in the resultant magnetomotive force, which can detrimentally impact machine performance, particularly in terms of torque ripple. In the context of wind energy conversion, maintaining low torque ripple is an essential and demanding prerequisite. Medium-speed wind generators present a good trade-off between high energy yield and low gearbox ratios. So far, medium-speed non-overlap winding wound-rotor synchronous generator (WRSG) technologies have been limited to 10/12 and the less common 16/18 pole/slot combinations. In this study, the analysis of a high-pole number combination (24/27 pole/slots) non-overlap WRSG is carried out to theoretically and comparatively predict the electromagnetic and radial force mechanical stress performance analysis with the 16/18 machine with a phase-shifted non-overlap winding (PSW), at 5 MW power level. The study, which is founded on the finite element analysis (FEA) technique, shows that the 24/27 machine exhibits comparable average torque and torque ripple, lower core losses and significantly reduced radial forces compared to the 16/18 PSW-WRSG. However, the 16/18 PSW-WRSG has a 50% reduction in the radial forces compared to the conventional 16/18 non-overlap winding. Experimental vibration analysis of a 3 kW 16/18 WRSG test machine confirms the radial force and vibration reduction in the phase-shifted winding. Full article
(This article belongs to the Special Issue Energy, Electrical and Power Engineering: 3rd Edition)
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12 pages, 2440 KiB  
Article
Effect of the Arc Extinguishing and Insulation Properties of C4F7N/CO2 Mixtures with Oxygen Addition: Experimental Investigations and Comparative Analysis
by Dongyu Guo, Xiaolong Li, Wen Wang and Zhenxin Geng
Energies 2024, 17(17), 4202; https://doi.org/10.3390/en17174202 - 23 Aug 2024
Viewed by 557
Abstract
The C4F7N/CO2 mixture is considered one of the most promising alternatives to sulfur SF6. Recent studies have shown that the addition of O2 to the C4F7N/CO2 mixture can suppress carbon [...] Read more.
The C4F7N/CO2 mixture is considered one of the most promising alternatives to sulfur SF6. Recent studies have shown that the addition of O2 to the C4F7N/CO2 mixture can suppress carbon precipitation following electric arc discharges. This paper conducts arc-burning experimental research on SF6, 10%C4F7N/90%CO2, and 10%C4F7N/85%CO2/5%O2 mixtures. Measurements were taken of the arc voltage and arc current under a 10 kA breaking current for these three gases. Additionally, the pressure at the nozzle throat during arc and cold flow conditions, as well as the pressure in the storage chamber, were measured. The post-arc current and Rate of Rise of Recovery Voltage (RRRV) for the three gases were calculated. The study also compared the solid precipitates in the gas medium after multiple arc-burning experiments. The results indicate that adding O2 to the C4F7N/CO2 mixture can increase the pressure at the nozzle throat during the arc phase, and the inclusion of O2 has minimal impact on the peak arc-extinguishing voltage and critical RRRV. It is hypothesized that a small amount of oxygen has a negligible effect on the thermal recovery properties of the C4F7N/CO2 mixture, while also inhibiting the precipitation of carbon following electric arc discharges. This research could provide a reference for developing and optimizing eco-friendly high-voltage circuit breakers. Full article
(This article belongs to the Special Issue Energy, Electrical and Power Engineering: 3rd Edition)
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Review

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19 pages, 1903 KiB  
Review
A Survey on the Sustainability of Traditional and Emerging Materials for Next-Generation EV Motors
by Francesco Lucchini, Riccardo Torchio and Nicola Bianchi
Energies 2024, 17(23), 5861; https://doi.org/10.3390/en17235861 - 22 Nov 2024
Abstract
The transportation sector is experiencing a profound shift, driven by the urgent need to reduce greenhouse gas (GHG) emissions from internal combustion engine vehicles (ICEVs). As electric vehicle (EV) adoption accelerates, the sustainability of the materials used in their production, particularly in electric [...] Read more.
The transportation sector is experiencing a profound shift, driven by the urgent need to reduce greenhouse gas (GHG) emissions from internal combustion engine vehicles (ICEVs). As electric vehicle (EV) adoption accelerates, the sustainability of the materials used in their production, particularly in electric motors, is becoming a critical focus. This paper examines the sustainability of both traditional and emerging materials used in EV traction motors, with an emphasis on permanent magnet synchronous motors (PMSMs), which remain the dominant technology in the industry. Key challenges include the environmental and supply-chain concerns associated with rare earth elements (REEs) used in permanent magnets, as well as the sustainability of copper windings. Automakers are exploring alternatives such as REE-free permanent magnets, soft magnetic composites (SMCs) for reduced losses in the core, and carbon nanotube (CNT) windings for superior electrical, thermal, and mechanical properties. The topic of materials for EV traction motors is discussed in the literature; however, the focus on environmental, social, and economic sustainability is often lacking. This paper fills the gap by connecting the technological aspects with sustainability considerations, offering insights into the future configuration of EV motors. Full article
(This article belongs to the Special Issue Energy, Electrical and Power Engineering: 3rd Edition)
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20 pages, 333 KiB  
Review
Fault Diagnosis in Electrical Machines for Traction Applications: Current Trends and Challenges
by Marco Pastura and Mauro Zigliotto
Energies 2024, 17(21), 5440; https://doi.org/10.3390/en17215440 - 31 Oct 2024
Viewed by 443
Abstract
The widespread diffusion of electric vehicles poses new challenges in the field of fault diagnostics. Past studies have been focused mainly on machines designed for industrial applications, where the operating conditions and requirements are significantly different. This work presents a review of the [...] Read more.
The widespread diffusion of electric vehicles poses new challenges in the field of fault diagnostics. Past studies have been focused mainly on machines designed for industrial applications, where the operating conditions and requirements are significantly different. This work presents a review of the most recent studies about fault diagnosis techniques in electrical machines feasible for traction applications, with a focus on the most adopted approaches of the last years and on the latest trends. Considerations about their applicability for electric vehicle purposes, along with some areas that require further research, are also provided. Full article
(This article belongs to the Special Issue Energy, Electrical and Power Engineering: 3rd Edition)
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