International Journal of Applied Electromagnetics and Mechanics - Volume 70, issue 4

Authors: Rao, Shaowei | Zou, Guoping | Yang, Shiyou | Khan, Shoaib Ahmed

Article Type: Research Article

Abstract: An artificial neural network (ANN) based methodology to diagnose transformer faults is proposed. The synthetic minority over-sampling technique (SMOTE) is used to solve the imbalance in the dataset. The SMOTE is improved by introducing a full cycle of creating synthetic samples from minority class samples for the goals that the over-sampled ratio can be automatically determined and the sample size of each category can be completely consistent. The contents of dissolved gases in transformer oils are treated as the original features. The optimal features combination for ANN is determined by comparing the performances of the ANN when different feature combinations …are used. The performances of different activation functions used in the ANN are investigated to give the optimal one. The tested results show the high accuracy (97.92%) of the proposed methodology if the optimum feature combination and activation function are used. Show more

Keywords: Artificial neural network, fault diagnosis, SMOTE, transformer

DOI: 10.3233/JAE-210227

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 70, no. 4, pp. 345-355, 2022

Authors: Li, Daiyan | Zhang, Yanli | Jing, Ying | Wang, Zhen | Xie, Dexin

Article Type: Research Article

Abstract: A large number of experimental observations show that under two-dimensional (2-D) rotational magnetization, there is a complicated relationship between the magnetostrictive strain and magnetic flux density. In this paper, the magnetostrictive characteristics in a non-oriented electrical steel sheet under 2-D magnetization are measured and modelled based on the experimental system developed by the laboratory. The in-plane magnetostrictive strain tensor under the 2-D magnetization is expressed as nonlinear superposition of dynamic magnetostrictive strain in the rolling direction (RD) and transverse direction (TD), respectively. The magnetostriction’s first derivative with respect to magnetization depicts the pinning effect and the interaction among magnetic domains …which result in the hysteresis behaviour. And based on the particle swarm optimization (PSO), the model parameters are identified. The validity of the proposed model is verified by comparing the calculation results with the experimental ones. Studies have shown that the magnetostrictive properties in an electrical steel sheet have strong hysteresis behaviour under the 2-D magnetization, and the model proposed here can well characterize these characteristics. Show more

Keywords: Electrical steel sheet, magnetostriction, mathematical model, 2-D magnetization

DOI: 10.3233/JAE-210228

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 70, no. 4, pp. 357-365, 2022

Authors: Yuan, Wei-Ying | You, Hong-Sen | Yuan, Jian-Sheng

Article Type: Research Article

Abstract: Previously, 36 TEAM benchmark problems have been established, used to verify the numerical calculation methods of electromagnetic fields. Among them, there is only one problem related to the magnetic field considering magnetic hysteresis, which is problem 32. The results of it are obtained by experimental measurement. In this paper, a same kind of benchmark problem is proposed, in which the field results are obtained by using analytical method. This benchmark problem can be used to verify both 2D and 3D numerical calculation methods. The analytical solving process of the problem is that H is obtained by using Ampere’s law, …then B is calculated based on the hysteresis model of the material, so that the field distribution results are formed. The required hysteresis model could be any kind, such as Preisach model, J–A model, etc. As long as the same kind of model is used both in the benchmark problem and in the numerical method, the numerical method can be verified through the proposed benchmark problem. Considering the form of J–A hysteresis model required by the benchmark problem does not exist, which is the field separation-based forward dynamic J–A model, it is derived based on the forward static J–A model. Show more

Keywords: Benchmark problem, field separation-based forward dynamic J–A model, magnetic hysteresis, numerical calculation method

DOI: 10.3233/JAE-210229

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 70, no. 4, pp. 367-375, 2022

Authors: Zhang, Tao | Liu, Xuechao | Zhang, Weirui | Liu, Ruigang | Xu, Canhua

Article Type: Research Article

Abstract: Magnetic induction tomography (MIT) has been proposed as a novel, non-invasive, and non-contact technique for diagnosing brain injuries. The design of the hardware system of MIT is a challenging research area. In this study, we constructed a 16-coil MIT simulation model with an actual cranio-cerebral anatomical structure in COMSOL. We analysed the factors which influence the MIT signal by constructing different types of haemorrhagic stroke models. In addition, the safety of MIT devices was evaluated in detail using the specific absorption rate. The results show that the phase noise of the hardware data acquisition system should be less than 0.001° …for the detection of a small peripheral haemorrhage with 5 mL. The result of the specific absorption rate shows that the security of MIT equipment should not be overlooked, and we need to establish a trade-off between signal intensity and device security. This study can provide data to support additional improvements in the performance of hardware systems in the future. Show more

Keywords: Head model, magnetic induction tomography, numerical simulation, three-dimensional modelling

DOI: 10.3233/JAE-210231

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 70, no. 4, pp. 377-386, 2022

Authors: Su, Peng | Wang, Yiwei | Zhao, Guishu | Shen, Yi | Li, Yongjian | Zhou, Lingkang

Article Type: Research Article

Abstract: In this paper, power-sizing equations of rotor-permanent-magnet flux-switching (RPM-FS) machines are proposed and implemented, where the main decisive factors of the electromagnetic torque, namely electric loading and magnetic loading, are deduced, respectively. Although the topologies of RPM-FS machines are evolved from traditional stator-PM flux-switching machines, there are still seriously flux leakages between poles, and it is hard to derive the peak value of the air-gap flux density directly. Hence, a local simplified magnetic equivalent circuit is utilized to calculate the magnetic loading, which is crucial for the power-sizing equation. The influences of the pole-to-pole flux-leakages and harmonics in back-EMF are …considered to improve the calculated accuracy of the power-sizing equation. Consequently, the electromagnetic torque can be predicted with acceptable accuracy. The feasibility of the power-sizing equation is verified by the finite element analysis and experimental results. Show more

Keywords: Rotor-permanent-magnet, flux-switching, sizing equation, magnetic equivalent circuit

DOI: 10.3233/JAE-210232

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 70, no. 4, pp. 387-396, 2022

Authors: Zhou, Xiaoyan | Zhang, Xiumin | Jiao, Chaoqun | Zhang, Jiangong | Gan, Zheyuan

Article Type: Research Article

Abstract: At present, a large number of high-voltage transmission lines have gradually become a key factor that interferes with the quality of surrounding radio communications. In the study of passive interference of transmission lines, the modeling of iron towers affects the accuracy of calculation results. In order to provide reliable data reference for the research of protective measures and interference suppression methods, aiming at the line model of transmission line tower, taking the tower structure and auxiliary angle-steel as variable factors, this paper studies its influence on the calculation results of passive interference. Three tower models with typical structures and obvious …differences are selected, and the models using only the main material and the auxiliary material angle-steel are established respectively. The calculation results of passive interference under different frequency incident waves are compared. The final conclusion shows that with the increase of incident wave frequency, the passive interference caused by the three transmission tower models increases gradually, and the effect of auxiliary angle-steel is more and more obvious. Show more

Keywords: Auxiliary angle-steel, ultra-high voltage transmission line, passive interference, tower modeling

DOI: 10.3233/JAE-210233

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 70, no. 4, pp. 397-406, 2022

Authors: Ai, Liwang | Miao, Sen | Li, Na | Gao, Caixia | Feng, Haichao | Xu, Xiaozhuo

Article Type: Research Article

Abstract: The high temperature superconducting (HTS) magnetic levitation is actually a self-stable levitation with multi-degree-of-freedom (DoF). However, the research of HTS magnetic levitation focuses on the axial or radial levitation behaviour with single-DoF motion independently. This article mainly discusses the 3-D modelling and the levitation behaviours of an eccentric superconductor-permanent magnet (SC-PM) system with multi-DoF motion. Firstly, the Power-Law E − J relation is used to obtain the relationship of equivalent conductivity-electric field strength for the superconductor. Then, a 3-D finite element model (FEM) of SC-PM system is established and calculated in software MagNet. At the …same time, the result of the simulation is verified by the experimental measurements. The axial levitation behaviour is analysed by establishing and solving the 3-D FEM in eccentric SC-PM system with different multi-DoF motions. The results show that the maximum axial levitation force decreases with the increase of the static eccentricity distance. When the PM rotor exhibits dynamic eccentricity, the axial levitation force presents periodic fluctuations of which the amplitude and period are related to the dynamic eccentric distance and speed. Show more

Keywords: Finite element model, levitation behaviour, multi-degree-of-freedom, SC-PM system

DOI: 10.3233/JAE-210234

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 70, no. 4, pp. 407-415, 2022

Authors: Chen, Qingbin | Zhang, Xu | Chen, Wei | Wang, Cong

Article Type: Research Article

Abstract: Planar spiral coil made of solid wire is widely used in wireless power transfer without magnetic core in high frequency operation system. Based on the magnetic field distribution of planar spiral coil and high frequency eddy current loss mechanism, the influence of magnetic field strength, frequency, and wire gauge on the AC resistance of winding are analysed. It reveals that the coil loss can be reduced by designing the wire gauge. Then the magnetic field strength and the winding loss calculation model are built, based on which the double wire gauge for segmental winding structure is proposed. This method can …reduce the AC resistance and improve the quality factor on the premise of keeping inductance constant at high frequency. Through simulation and experiment, the AC resistance of coil based on the double wire gauge scheme can be greatly reduced comparing to the traditional method and the efficiency of the prototype is increased by 4%, which verifies the theory analysis to be correct and flexible. Show more

Keywords: Coil optimization, the AC resistance, wire gauge, wireless power transfer

DOI: 10.3233/JAE-210235

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 70, no. 4, pp. 417-432, 2022

Authors: Li, Cailian | Li, Yuanyuan | Liu, Guoqiang

Article Type: Research Article

Abstract: Magneto-Acousto-Electrical Tomography (MAET) has the advantage of high spatial resolution and high image contrast and is expected to achieve early breast cancer diagnosis. At present, the density of biological tissue is usually assumed to be the density of water. The effect of density changes on the MAET signal has not been studied. Liposarcoma of the breast is a common malignant tumor. Unlike normal breast cancer which occurs in the gland, liposarcoma of the breast occurs in the fat of the breast. However, the fat density of the breast is widely distributed, which is different from that of liposarcoma. Therefore, it …is very important to study the effect of density change on the MAET signals. In this paper, a finite element simulation model is established to consider the influence of density variation on the MAET signal. The simulation results show that an increase in density reduces the amplitude of the original MAET signal. The degree of reduction in signal amplitude is proportional to the increase in signal density. The simulation results are consistent with the theoretical analysis. Finally, the MAET experimental platform is built to validate the simulation results of MAET signals. The simulation and experiment results show that the change of density greatly influences the detection of breast liposarcoma based on MAET. It cannot be directly equivalent to the density of water. The results of this study indicate that MAET is expected to detect the early diagnosis of breast liposarcoma. Show more

Keywords: Density, liposarcoma, MAET

DOI: 10.3233/JAE-210236

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 70, no. 4, pp. 433-443, 2022

Authors: Ren, Shuting | Li, Yong | Liu, Zhengshuai | Zainal Abidin, Ilham Mukriz | Chen, Zhenmao

Article Type: Research Article

Abstract: Macroscopic defects such as corrosion in nonmagnetic Conductors Under Stress (CUS) are more universal than those within the zero-stress environment, and result in complicated characteristics regarding the electrical properties of the conductors. In this paper, Gradient-field Pulsed Eddy Current technique (GPEC) is intensively investigated for imaging and evaluation of corrosion in CUS. The influence of stress on electrical properties of nonmagnetic CUS with corrosion is analysed via multi-physics simulations and experiments. The correlations between characteristics of corrosion in CUS and the GPEC signal and its features are established and scrutinised. An image processing method reproducing defect images for quantitative assessment …of detected corrosion in CUS is proposed. Show more

Keywords: Conductors under stress, corrosion imaging, electromagnetic non-destructive evaluation, gradient-field pulsed eddy current, multi-physics simulations

DOI: 10.3233/JAE-210237

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 70, no. 4, pp. 445-459, 2022

Authors: Li, Yongjian | Li, Yating | Cheng, Zhiguang | Tian, Yakun

Article Type: Research Article

Abstract: HVDC (High Voltage Direct Current) transmission equipment generally works under AC–DC hybrid excitation (with both DC-bias components and harmonics), increasing the loss of magnetic components and even causing local overheating. In order to study the influence of AC–DC hybrid excitation on the performance of magnetic materials, the loss properties of electrical silicon steel under AC–DC hybrid excitation are measured and modelled. This paper improves the iron loss model based on the Bertotti loss model by introducing a new term caused by DC bias. In addition, the improved loss model is combined with the transient loss model, and the iron loss …calculation is performed based on the results of the TEAM P21 extended model. The comparison between the calculated and measured loss shows that the improved loss model is more accurate than the traditional one. Show more

Keywords: AC–DC hybrid excitation, Bertotti loss model, TEAM Problem 21 Family, iron loss

DOI: 10.3233/JAE-210238

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 70, no. 4, pp. 461-470, 2022

Authors: Wang, Yingying | Yu, Jiahui | Yang, Xinyu | Zhang, Xu

Article Type: Research Article

Abstract: The core of the inductor used in a high-frequency switching power converter usually operates on a local magnetization curve under DC bias, and is easily saturated. In this paper, a novel inductor with a metamaterial core is proposed, in which the magnetic core is replaced by coil units. The coil units can achieve an equivalent permeability comparable to that of the commonly used magnetic powder core material at the working frequency. The design and analysis methods for an inductor with a metamaterial core are described in detail. The proposed inductor is insensitive to the DC component, but can store and …transmit the energy of the pulse component. The inductor with a metamaterial core has low loss and is lightweight, which helps increase the power density. Show more

Keywords: Buck circuit, equivalent permeability, filter inductor, metamaterial core

DOI: 10.3233/JAE-210239

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 70, no. 4, pp. 471-478, 2022

Authors: Huo, Tianchen | Yang, Wenrong | Qiao, Yiwei | Zhang, Haojie | Chen, Guohang

Article Type: Research Article

Abstract: The high–low voltage DC/DC converter of electric vehicle produces high du ∕dt and di ∕dt due to the high operating frequency of the power devices, which introduce nonnegligible electromagnetic interference. In this paper, the power devices control signals of the high–low voltage DC/DC converter were modulated by periodic signals, the influence of the modulation frequency, the maximum frequency deviation and the modulation waveform on the conducted electromagnetic interference were analyzed. Combined with the published data of the phase-shifted full-bridge circuit of the high–low voltage DC/DC converter, the spread-spectrum modulation control signal model and power circuit model were established …in MATLAB/Simulink and PSIM, and co-simulations were carried out with different modulation parameters. The interference suppression effects of three test frequency bands required by CISPR 25 were tested; the optimal parameters for the periodic frequency modulation of the high–low voltage DC/DC converter in electric vehicle were proposed. Show more

Keywords: Co-simulation, DC/DC converter, electromagnetic interference suppression, periodic frequency modulation

DOI: 10.3233/JAE-210240

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 70, no. 4, pp. 479-490, 2022

Authors: Zhang, Tianheng | Guo, Miaomiao | Xu, Guizhi

Article Type: Research Article

Abstract: Intermittent theta burst stimulation (iTBS) is a new magnetic stimulation paradigm and has been widely used in the study of neurological diseases. However, its electrophysiological regulation mechanism remains unclear. To explore the effect of iTBS on brain cognitive function and its electrophysiological mechanism, the aged rats were treated with iTBS, and the local field potentials (LFPs) in the ventral hippocampus (vHPC) and medial prefrontal cortex (mPFC) were acquired during working memory (WM) tasks. The effect of iTBS stimulation on the correlation network synergy and topological attributes across brain regions of WM in aged rats was investigated. The results showed that …iTBS enhanced the correlation network connection characteristics of vHPC and mPFC brain regions during WM, and improved the behavioral performance of aged rats. This study has important research significance for the mode optimization and clinical application of transcranial magnetic stimulation. Show more

Keywords: Brain network, hippocampus-prefrontal cortex, theta burst stimulation, working memory

DOI: 10.3233/JAE-220001

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 70, no. 4, pp. 491-500, 2022

Authors: Liu, Zhao | Zhu, Lihua | Zhong, Sichong | Wang, Yanzhao | Zhang, Jiangong

Article Type: Research Article

Abstract: Active noise reduction system is widely used in production and life because of its good noise reduction effect in low frequency band, easy installation, high practicability and good economy. This paper focused on the compilation of active noise reduction algorithms and the overall system debugging, and explored the factors that affected the active noise reduction. In order to realize the software part of the active noise reduction system, the LMS adaptive filtering algorithm was written and non-linearity function and auxiliary machine learning algorithm was used. Then the hardware system was built for the overall joint debugging of software and hardware. …Combined with the practical application background of electrical equipment engineering, the influence of the angle, number of speakers and the distance from electrical equipment on the noise reduction effect were studied. The results showed the overall noise reduction in the experiment was about 6 dB, which proved that the active noise reduction system proposed in this paper is effective. Show more

Keywords: Active noise reduction, adaptive filtering, LMS, influence of noise reduction

DOI: 10.3233/JAE-220002

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 70, no. 4, pp. 501-513, 2022

Authors: Ruowei, Qu | Shifen, Wang | Zhengfang, Liu | Junhua, Gu | Guizhi, Xu

Article Type: Research Article

Abstract: Epilepsy is one of the most serious neurological diseases in the world. The mesial temporal lobe epilepsy (MTLE), especially hippocampal sclerosis (HS) is the most common pathological causes of epilepsy. With the development of computer visualization technology, there are many auxiliary diagnostic approaches based on deep learning algorithms. However, the traditional 2D-CNN framework can only accept single layer inputs. In such case, the associations between the brain planes are ignored, which may lead to misdiagnosis or missed diagnosis. 3D-CNN framework can accept cubes as the input of the neural network, so that network parameters will carry more structural and logical …information of the brain in the spatial domain. Therefore, this study designed a 3D-CNN framework for MTLE diagnosis in T2-FLAIR MRI images. We retrospectively collected 15 patients with the MTLE and 15 age-matched controls who underwent T2-FLAIR studies. Then, we proposed three 3D-CNN based on ResNet to identify symmetrical differences in the corresponding areas of the brain in both sides. The symmetrical cubes were combined as the inputs for the 3D-CNN framework. Performances of the proposed framework were compared with radiomics algorithms and visual assessment. The proposed 3D-CNN based on ResNet-34 performs the best among all the algorithms. Moreover, due to the non-inferiority testing for paired data, the proposed 3D-CNN frameworks based on the ResNet were not inferior to that of visual assessment which was unblinded to the clinical information. The proposed 3D-CNN framework could diagnosis MTLE in MRI images accurately and efficiently, which might be applied as a computer-assisted approach for the future diagnosis of epilepsy patients. Show more

Keywords: Epilepsy, hippocampal sclerosis, CNN, MRI, computer aided diagnosis

DOI: 10.3233/JAE-220003

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 70, no. 4, pp. 515-523, 2022

Authors: Li, Dandan | Wu, Yuxiang | Zhu, Shilei | Li, Zhongkang

Article Type: Research Article

Abstract: Aiming at the weak capacity of the parameter identification methods of Jiles–Atherton (J–A) hysteresis model, such as slow convergence speed and low convergence accuracy, an improved sparrow search algorithm (IM-SSA) is proposed based on mutation crossover operator and T-distribution perturbation strategy in this paper to improve the convergence speed and accuracy of parameter identification method. Firstly, the initial population of the sparrow search algorithm is enriched by Tent chaotic sequence, which expand the search area. Then, the adaptive crossover and mutation operator is introduced into the finders population to enrich the diversity of the finders population and balance the global …and local search ability of the algorithm. Secondly, the T-distribution perturbation or differential mutation is used to perturb the population after each iteration according to the individual characteristics, which can avoid the population singularity in the later stage of the algorithm and enhance the ability of jump out of the local optimal value of the algorithm. Finally, the proposed parameter identification method is used to identify the parameters of the J–A hysteresis model, which are used to simulate the magnetic properties of Non-oriented silicon steel sheets with different magnetic induction intensity. The calculation result is compared with the experiment ones. The results proved that the proposed method has faster convergence speed and higher convergence accuracy. Show more

Keywords: Cross-mutation operator, improved sparrow search algorithm, J–A hysteresis model, parameter identification, t-distribution perturbation

DOI: 10.3233/JAE-220050

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 70, no. 4, pp. 525-535, 2022