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

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