Electromagnetic Analysis Research Articles

Optimal Design and Analysis of High-Frequency Isolation Transformer for Switched-Mode Power Converters

High-frequency (HF) transformers have gained great interest in recent years due to the advent of powerful soft magnetic materials with low core loss in semiconductor power switches. Also, the optimal design of the HF transformer is a significant issue for high-performance energy conversion systems. In this paper, a 40W 50/12.5/25 V universal input and two output discontinuous-conduction mode (DCM) flyback transformer is designed by using mathematical calculations and analyzed via 3D ANSYS/Maxwell simulation including electromagnetic and loss analysis. It is shown that the simulation results accounting for hysteresis losses, eddy current losses, copper losses, and magnetic flux density determine the accuracy of the mathematical model calculation. Analyzes are performed at 100 kHz frequency levels. Results obtained will include core magnetic flux density, core/copper losses, leakage/magnetizing inductances, windings parasitic capacitances, input/output voltage, current values, and all design parameters. Finally, the proposed HF transformer's overall efficiency is calculated and presented. Significantly, the HF transformer achieves 97.8% efficiency thanks to the transformer's core and coil selection, B-H and B-P characteristics, one-to-one dimension design, and mesh operation. The dynamic and mathematical results of the designed transformer demonstrate the design and efficiency success

Frequency domain solution method for electromagnetic influence analysis on torsional vibrations

In electric motor-driven machines, mechanical torsional dynamics are nonlinearly coupled with the electrical system through the electromagnetic torque and the counter-electromotive force. In this paper, an approach based on small-signal linearization is proposed for modeling the steady-state torsional dynamics of the coupled system. Using the linearized model, resonance interference diagrams, torsional response, and stability can be evaluated rapidly across numerous operating points, while accurately accounting for the electromagnetic effects. The model is validated with conventional time-stepping simulations of two induction machines. An example analysis of a 3 MW motor-driven compressor train displays the modification of torsional properties due to the electromagnetic coupling effect and explains the mechanism of torsional destabilization. Finally, previously published measurements of a 37 kW motor test bench are considered to validate the instability of the elastic torsional mode predicted by the model.

Electromagnetic Stress Analysis of High-Temperature Superconducting Coated Conductor Strip After Partial Debonding at the Edge Under the Combined Transport Current and Magnetic Field

Electromagnetic Stress Analysis of High-Temperature Superconducting Coated Conductor Strip After Partial Debonding at the Edge Under the Combined Transport Current and Magnetic Field

Electromagnetic Design and Mechanical Analysis of a 28.2-T/1.2-GHz High-Field NMR Magnet

Electromagnetic Design and Mechanical Analysis of a 28.2-T/1.2-GHz High-Field NMR Magnet

Design of a Technology Verification Platform for Space Electromagnetic Interference Signal Testing and Analysis

This paper designs a space electromagnetic interference signal test and analysis technology verification platform. The article firstly introduces the general scheme of the technical verification platform and then describes each component unit of the hardware and the overall structure of the software in detail. The platform can achieve a 10 MHz ~ 50 GHz working frequency band, 1.2 GHz acquisition and real-time recording bandwidth, 6 GB/s recording rate, and 12 TB recording capacity.

Flexible and Large‐Scale Liquid Metal Frequency‐Selective Surfaces: Enhanced Tuning through Mechanical Reconfiguration

The tuning capability is crucial for broadening the application possibilities of frequency‐selective surfaces (FSSs). Flexible and stretchable FSSs have attracted widespread research interest due to their ability for adhering to curved surfaces conformally and reconfiguring electromagnetic (EM) wave transmission performance mechanically. However, conventional metal FSSs lack sufficient flexibility and deformability due to material constraints, resulting in diminished durability and limited EM tuning range. In this article, a design approach for flexible liquid metal FSS (LMFSS), which can conform to curved structures and achieve a wide range of EM wave tuning via mechanical stretching without structural damage, is presented. The fabrication of LMFSS is simplified using silicone elastomer curing and liquid metal inkjet printing, avoiding the complexities of traditional microchannel techniques. In the experimental results, it is demonstrated that the designed LMFSS achieves a tuning range of up to 16% under biaxial stretch strains not more than 25%. The tuning mechanism is explored through mechanical–EM simulations and equivalent circuit analyses. Additionally, the tuning phenomenon observed in another flexible LMFSS in this study underscores the portability of the design approach and tuning mechanism. In this research, a promising direction for tunable flexible LMFSS applications is offered.

Cross-device Portability of Machine Learning Models in Electromagnetic Side-Channel Analysis for Forensics

The possession of smart devices has ingrained itself into daily life. Therefore, smart devices, such as IoT and smartphones, are crucial sources of evidence in instances where criminal activity occurs. Due to the challenges in traditional digital forensic techniques involving smart devices, it has been recently proposed in the literature to leverage electromagnetic side-channel analysis (EM-SCA) for the purpose. This paper identifies and discusses an important barrier that exists in the application of EM-SCA for digital forensics that hinders its successful use, namely, the issue of cross-device portability of machine learning (ML) models that are used for EM-SCA. Firstly, the paper empirically evaluates the possibility of using trained ML models to extract forensic insights from EM radiation data of IoT devices. During this empirical study, the inability to reuse a trained ML model across different devices is identified. Secondly, the paper surveys the literature in search of related work that has studied the use of EM-SCA to gather information from smart devices. The purpose of the survey is to identify whether any existing work has been able to introduce potential approaches to enable cross-device portability of ML models in EM-SCA. The findings of this survey point to the fact that the identified problem still exists and requires further studies opening the door to future research.

Electromagnetic modeling and analysis based on multilayer domain structure for GMI behavior in high frequency

Existing theoretical models on the frequency dependence of the magnetoimpedance (MI) in ferromagnetic microwires primarily describe the MI phenomenon at the limiting cases of lower MHz (<several hundred MHz) or higher GHz (>several GHz) ranges. However, in the intermediate region between these two ranges, known as the transition region, MI curves undergo complex transformations. These transformations have been documented in the literature, but their underlying causes remain poorly understood. Unambiguous knowledge of the domain structure and its correlation with MI properties is essential for elucidating this behavior. In this study, we have, for the first time, observed the inner core magnetic structure of Co-based microwires and revealed its relationship with the high-frequency MI effect. A distinct magnetic structure comprising longitudinal domains in the inner core (IC), circular domains in the outer shell (OS), and a transition region (TR) has been identified. This structure originates from compositional gradients and residual stresses during microwire fabrication. The IC/TR/OS structure manifests in the complex transformations of the MI behavior, exhibiting a turning point at GHz frequencies before the characteristic double MI peak. We developed a multilayer planar model that considers this more realistic magnetic structure, including the TR layer. This model successfully reproduces the key features of the MI curves and provides deeper insights into the high-frequency MI phenomenon. Our findings pave the way for optimizing the sensing capabilities of Co-based ferromagnetic microwires and demonstrate the potential of using high-frequency MI measurements to map their magnetic microstructures.

Electromagnetic Field and Variable Inertia Analysis of a Dual Mass Flywheel Based on Electromagnetic Control

The moment of inertia of the primary flywheel and the secondary flywheel in a dual mass flywheel (DMF) directly affects the vibration damping performance in an automotive driveline. To enable better minimization of vibration and noise by changing the moment of inertia of the DMF to adjust the frequency characteristics of the automotive driveline, a new variable inertia DMF structure is proposed by introducing electromagnetic devices. The finite element simulation model of the electromagnetic field of an electromagnetic device is established, the electromagnetic field characteristics in the structure are analyzed, and the variation in the electromagnetic force under different air gaps and current conditions is obtained. The electromagnetic force test system of the electromagnetic device is constructed, and the validity of the finite element simulation analysis of the electromagnetic field of the electromagnetic device is verified. A mechanical model of the electromagnetic device is established to analyze the characteristics of the displacement of the moving mass in the structure as well as the variation in the moment of inertia of the DMF at different rotational speeds and currents. The maximum adjustable proportion of its moment of inertia can reach 15.07%. A torsional model of the automotive driveline is established to analyze the effect of variable inertia DMF on the resonance frequency of the system under different currents. The results show that the electromagnetic device introduced in the DMF can realize the active adjustment of the moment of inertia and enable the resonance frequency to decrease with increasing rotational speed, which expands the idea of optimizing the vibration damping performance of the DMF and provides a reference for better control of the torsional vibration of the automobile or other mechanical transmission systems.

Electromagnetic and Mechanical Stress Analysis of a 5 MW High-Pole Non-Overlap Winding Wound-Rotor Synchronous Wind Generator

Electromagnetic and Mechanical Stress Analysis of a 5 MW High-Pole Non-Overlap Winding Wound-Rotor Synchronous Wind Generator

Preparation of M-type barium ferrite submicron absorbing powder by one-step high-temperature ball milling and its particle structure regulation

This study investigates a simple and rapid process for directly preparing M-type barium ferrite using high-temperature ball milling. By adjusting the rotation speed of the high-temperature ball milling, the morphology and size of the powder can be altered to regulate its electromagnetic properties, aiming for an overall good absorbing effect. The powder’s morphology, agglomeration properties, elemental valence states, and electromagnetic parameters were characterized using SEM, BET, XPS, EDS, and VNA. The results show that as the milling speed increases, the particle size of the M-type barium ferrite decreases, transitioning from the typical hexagonal flake particles to spherical block particles, forming a porous loose structure with richer dielectric loss mechanisms and enhanced electromagnetic wave loss capacity. Electromagnetic loss performance analysis indicates that at a milling speed of 50 rpm, the powder achieves the best electromagnetic loss of −61.16 dB at a matching thickness of 8.77 mm and a microwave absorption bandwidth of 4.1 GHz.

Electromagnetic field analysis by the symplectic integrator method

Electromagnetic field analysis by the symplectic integrator method

The Development of a High-Efficiency Small Induction Furnace for a Glass Souvenir Production Process Using Multiphysics

A small induction furnace (SIF), which has the important components of copper coils, a ceramic jig, and a graphite crucible, employed for a glass souvenir production process, has been developed as a form of clean technology for multiphysics, consisting of electromagnetics analysis (EA) and thermal analysis (TA). First, two experiments were established to measure parameters for multiphysics results validation and boundary condition settings. Then, the parameters were applied to multiphysics, in which the EA revealed magnetic flux density (B) and ohmic losses, and the TA reported a temperature consistent with the experimental results, confirming the multiphysics credibility. Next, a ferrite flux concentrator was added to the SIF during development. Multiphysics revealed that PC40 ferrite, as a flux concentrator with a suitable design, could increase B by about 159% compared to the conventional SIF at the power of 1000 W. As expected, the B increases alongside the increase in power applied to the coils, and is more densely concentrated in the flux concentrator than in other regions, enhancing the production process efficacy. Lastly, the developed SIF was employed in the actual process and received good feedback from users. The novel research findings are the developed SIF and methodology, exclusively designed for this research and practically employed for a glass souvenir production process.

Physics-aware neural network-based parametric model-order reduction of the electromagnetic analysis for a coated component

AbstractFinite element (FE) analysis is one of the most accurate methods for predicting electromagnetic field scatter; however, it presents a significant computational overhead. In this study, we propose a data-driven parametric model-order reduction (pMOR) framework to predict the scattered electromagnetic field of FE analysis. The surface impedance of a coated component is selected as parameter of analysis. A physics-aware (PA) neural network incorporated within a least-squares hierarchical-variational autoencoder (LSH-VAE) is selected for the data-driven pMOR method. The proposed PA-LSH-VAE framework directly accesses the scattered electromagnetic field represented by a large number of degrees of freedom (DOFs). Furthermore, it captures the behavior along with the variation of the complex-valued multi-parameters. A parallel computing approach is used to generate the training data efficiently. The PA-LSH-VAE framework is designed to handle over 2 million DOFs, providing satisfactory accuracy and exhibiting a second-order speed-up factor.

Electromagnetic compatibility study of acoustoelectric logging detector

Abstract The acoustoelectric effect logging detector can achieve downhole acoustoelectric effect measurement, but the excitation of the acoustic transducer can generate significant electromagnetic interference (EMI) signals, it is difficult to effectively measure weak converted signals of acoustoelectric effect underground. The EMI problem of acoustoelectric effect logging detectors can be solved by studying EMI characteristics. Based on the analysis of the structure, measurement function, and measured interference signals of the receiving electrodes of the detector, the EMI sources, coupling paths, and sensitive components in the detector were studied. The basic process of EMI generated by high-voltage pulse excitation source of acoustic transducer is analysed, and two electromagnetic coupling interference analysis models for detectors, namely conductive coupling and borehole electromagnetic coupling, are established. This study can provide a fundamental method and reference for electromagnetic compatibility analysis of acoustoelectric effect logging detectors.

Electromagnetic Characteristics Analysis and Thrust Fluctuation Optimization in Integrated Propulsion, Levitation, and Guidance Systems

Electromagnetic Characteristics Analysis and Thrust Fluctuation Optimization in Integrated Propulsion, Levitation, and Guidance Systems

Literature review of specific techniques in catching and throwing in infield defense in baseball - retrospective article

&lt;p&gt;目的：內野手可以是整個棒球守備的核心，棒球守備各階段全身上下的協調，有許多值得探討的專項技巧。方法：本研究使用Google scholar，以Baseball infielder、內野、野球守備、內野捕球、守備ゴロ等關鍵字，搜尋台灣、日本、美國三國關於棒球內野守備專項技巧的文獻做歸納，以不同角度探討內野守備的專項技巧：一、內野守備接球，二、內野守備傳球，三、守備的分期與各分期之動作控制。結果：本篇回顧性論文發現，一、移動腳步到好接球的彈跳點是良好守備的關鍵。二、減少軸心腳在接球位置上的變化和較為前面的接球點，對於接球的穩定性至關重要，甚至會影響到後續傳球的動能。三、精簡接傳的動作相較於增加傳球球速可能可以更能有效減少整體守備時間。四、優秀選手在接球的過程中會儘早讓軸心腳著地，並前期和中期將重心保留在軸心腳。五、內野手傳球在前導腳接觸時，軀幹向後扭轉和肘部伸展角度都會比投手小。結論：無論是接球前腳步移動的節奏和精確性，還是接球時的接球點和接短彈跳的能力，甚至是軀幹和骨盆前傾的時機點，對於內野守備過程都產生一定的影響。建議在日常練習時，就能將接短彈跳、腳步移動，納入訓練課表中，並且在動作過程中，加以檢視軀幹的姿勢，方能在比賽時擁有良好的守備表現。&lt;/p&gt; &lt;p&gt;&amp;nbsp;&lt;/p&gt;&lt;p&gt;The standing throw with run-up is the best approach to evaluate the performance of energy transfer and the efficiency of throwing motions for handball players. Purpose: This research aims at analyzing the usage of the standing throw with run-up among the handball players in Taiwan. The roles of body kinematics, strength of core muscles and standing balance of the drive leg played in the standing throw with run-up are also discussed. Methods: Nine Division I handball players from college went through a series of tests. The motions and the speed of the handball throwing were detected by a 3D electromagnetic motion analysis system and a sports radar gun, respectively. The maximum isometric muscle strength of trunks and hips were measured by a torque sensor and a home-made device of strength measurement. The standing balance of the drive leg was measured by a force plate with a mat. Results: The maximal shoulder external rotation angle in the arm cocking phase, the maximal trunk rotation velocity in the arm acceleration phase and the maximal shoulder horizontal adduction velocity showed moderate positive relationships with the ball velocity. The strength of back muscles had a moderate negative relationship with the ball velocity. The correlation between the balance ability of the drive leg and the ball velocity was not observed. Conclusion: The importance of proximal segments to the standing throw with run-up is analyzed by kinematical analysis. It is suggested that the energy of handball throwing is generated by the upper extremities or other limb segments in the processes of the standing throw with run-up. Our findings can serve as a helpful reference for both coaches and players.&lt;/p&gt; &lt;p&gt;&amp;nbsp;&lt;/p&gt;

Electromagnetic Performance Analysis, Prediction, and Multiobjective Optimization for U-Type IPMSM

Electromagnetic Performance Analysis, Prediction, and Multiobjective Optimization for U-Type IPMSM

Electromagnetic Analysis of the Demo Magnet System: Electrical Behavior of a Toroidal Field Coil During an Electrical Transient

Electromagnetic Analysis of the Demo Magnet System: Electrical Behavior of a Toroidal Field Coil During an Electrical Transient

Heat transfer modeling in a transformer using magneto-CFD analysis and GWO algorithm considering dynamic thermal model

One of the most expensive power system components is transformer. The correct use and health of the transformer increase the reliability of the power network.The transformer health is depend on careful planning for it. Therefore, hot spot temperature must be calculated for accurate transformer planning. Also, in order to increase the accuracy of transformer hot spot temperature estimation, the dynamic thermal model is used. On the other hand, the use of meta-heuristic algorithms has been less considered by researchers to calculate the transformer hot spot temperature. Thus, in this paper, the grey wolf, imperialist competitive and artificial bee colony algorithms are used to estimate the transformer hot spot temperature. Besides, electromagnetic analysis of the transformer is investigated using ANSYS-MAXWEL software. On the other hand, conjugate heat transfer modeling in the transformer is presented to compare the results with the grey wolf optimization algorithm. The results show that the grey wolf optimization algorithm can be a good alternative for transformer hot spot temperature estimation.