Magnetic Design Research Articles

Research on magnetic field characteristics of amorphous alloy and grain‐oriented silicon steel hybrid magnetic circuit iron core

AbstractAmorphous alloy and grain‐oriented silicon steel are commonly employed as soft magnetic materials for the preparation of transformer cores, but both materials have their advantages and disadvantages. Using only silicon steel or amorphous alloy for the preparation of the core makes it difficult to achieve both high design density and low no‐load loss characteristics. In order to achieve the magnetic performance advantages of both amorphous alloy and silicon steel in transformer core development and application, the authors design and develop a kind of amorphous alloy and grain‐oriented silicon steel hybrid magnetic circuit core to explore the amorphous alloy and grain‐oriented silicon steel at different ratios under the magnetic properties of matching law. Based on the amorphous alloy and grain‐oriented silicon steel core magnetic performance comparison characteristics, the authors establish a core magnetic circuit model and design a hybrid magnetic circuit core structure with different material ratios. The hybrid magnetic circuit core model is simulated and analysed to obtain the magnetic density distribution of the hybrid magnetic circuit core. A number of hybrid magnetic circuit core experimental models are produced, and the use of a magnetic property measurement platform is made for the hybrid magnetic circuit core measurements, to reveal the magnetic performance matching law of the hybrid magnetic circuit core, providing a good solution for power distribution in the hybrid magnetic circuit.

Regional Transformation: An Integrated System's Approach to Magnet Designation Utilizing High-Reliability Organization Implementation Strategies.

Synergistic opportunity exists between Magnet-aspiring environments and High Reliability Organization (HRO) cultures to elevate safety, quality, new knowledge, continuous improvement, hierarchical flattening, and frontline empowerment. Variation existed across a region's 15 hospitals regarding Magnet-readiness, leadership engagement, journey strategies, and resource capacity. Quality improvement (QI) methodology and a hybrid-hub-spoke-model (HHSM) were used to support region-wide Magnet designation, improve patient outcomes, and advance nursing research. HRO strategies were used region-wide to strengthen implementation and enculturation of Magnet excellence infrastructure. Nine facilities achieved Magnet recognition. Magnet sites demonstrated significantly lower falls with injury ( P =.012), lower health care-associated infections and hospital-acquired pressure injuries than non-Magnet sites. Nursing research studies increased 223%. Utilizing a HHSM and HRO strategies represent effective methods for supporting region-wide Magnet designation and continuous QI.

Backaction-evading receivers with magnetomechanical and electromechanical sensors

Today's mechanical sensors are capable of detecting extremely weak perturbations while operating near the standard quantum limit. However, further improvements can be made in both sensitivity and bandwidth when we reduce the noise originating from the process of measurement itself—the quantum-mechanical backaction of measurement—and go below this ‘standard’ limit, possibly approaching the Heisenberg limit. One of the ways to eliminate this noise is by measuring a quantum nondemolition variable such as the momentum in a free-particle system. Here, we propose and characterize theoretical models for direct velocity measurement that utilize traditional electric and magnetic transducer designs to generate a signal while enabling this backaction evasion. We consider the general readout of this signal via electric or magnetic field sensing by creating toy models analogous to the standard optomechanical position-sensing problem, thereby facilitating the assessment of measurement-added noise. Using simple models that characterize a wide range of transducers, we find that the choice of readout scheme—voltage or current—for each mechanical detector configuration implies access to either the position or velocity of the mechanical subsystem. This in turn suggests a path forward for key fundamental physics experiments such as the direct detection of dark matter particles. Published by the American Physical Society 2024

Nanofabrication, characterisation and modelling of soft-in-hard FeCo–FePt magnetic nanocomposites

Advanced nanofabrication exploiting e-beam lithography has been used to prepare nanocomposites consisting of periodic arrays of soft magnetic FeCo-based nano-inclusions of variable dimensions, embedded in a hard magnetic FePt matrix. Nanocomposites with non-magnetic (Pt) inclusions and single phase hard magnetic FePt microstructures were prepared as reference samples. The formation of Kirkendall voids in the soft-in-hard nanocomposites, because of annealing-induced diffusion, has been identified through high resolution imaging and chemical analysis. Replication of the μm-scaled nanocomposite and hard magnetic units over mm-scaled surfaces allowed global magnetic characterisation of magnetisation reversal using standard magnetometry. Magnetic force microscopy imaging was used for spatially resolved magnetic characterisation in different remanent magnetic states. Both of these experimental techniques were used to study the influence of the size, volume content and nature of the nano-inclusions on magnetisation reversal. The well-defined geometry and nano-scaled size of the inclusions render these nanocomposites as model systems for micromagnetic simulations and very good agreement was achieved between measured and simulated magnetisation reversal curves. This accordance motivates future in-silico optimisation of such soft-in-hard nanocomposites, which may serve as model systems to guide the design of new high performance bulk magnets which are less dependent on critical elements.

Neuroplasticity of visual brain network induced by hypoxia.

The effects of hypoxia on brain function remain largely unknown. This study aimed to clarify this issue by visual-stimulated functional magnetic resonance imaging design. Twenty-three college students with a 30-d high-altitude exposure were tested before, 1week and 3months after returning to sea level. Brain functional magnetic resonance imaging and retinal electroretinogram were acquired. One week after returning to sea level, decreased blood oxygenation level dependent in the right lingual gyrus accompanied with increased blood oxygenation level dependent in the frontal cortex and insular cortex, and decreased amplitude of electroretinogram a-wave in right eye; moreover, the bilateral lingual gyri showed increased functional connectivity within the dorsal visual stream pathway, and the blood oxygenation level dependent signals in the right lingual gyrus showed positive correlation with right retinal electroretinogram a-wave. Three months after returning to sea level, the blood oxygenation level dependent signals recovered to normal level, while intensively increased blood oxygenation level dependent signals in a broad of brain regions and decreased retinal electroretinogram were also existed. In conclusion, hypoxic exposure has long-term effects on visual cortex, and the impaired retinal electroretinogram may contribute to it. The increased functional connectivity of dorsal stream may compensate for the decreased function of retinal photoreceptor cells to maintain normal visual function.

Study on Winding Design of Dual Three-Phase Electrical Machines for Circulating Current Harmonics and Vibration Suppression

The dual three-phase electrical machines (DTP-EMs) have significant advantages and application potential in large-power and high reliability electromagnetic drive system. Nevertheless, one of the main operating challenges of DTP-EMs is the significant high-frequency circulating current harmonics when supplied with voltage-source inverters (VSIs), which will bring unexpected vibration and loss. This paper provides a thorough study on the mutual magnetic coupling effect and design criterion of dual three-phase winding. First, the mathematical model of DTP-EMs is established. Then, the internal mechanism of mutual magnetic coupling and the relationship among the mutual leakage inductance in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$x$</tex-math></inline-formula> - <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$y$</tex-math></inline-formula> subspace, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\alpha$</tex-math></inline-formula> - <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\beta$</tex-math></inline-formula> subspace and stator leakage inductance is revealed. Furthermore, the winding design criterion for DTP-EMs considering high-frequency circulating current harmonics and vibration suppression is proposed. It is drawn that full pitch is required for DTP-EMs to minimize the high-frequency current harmonics and vibration. Finally, two prototypes of the DTP-EM are built and tested to validate the theoretical analysis. This paper provides an effective winding design guide of DTP-EMs for the high-frequency current harmonics suppression and can also be expand to other multi-phase machines.

Study on a hybrid-produced magnetic-field Hall thruster

The increasing interest in all-electric, low-Earth orbit satellite constellations has stimulated the rapid development of electric propulsion technology, particularly low-power Hall thrusters. In this study, the difficulties in magnetic field design were analyzed in low-power Hall thrusters, and a new and efficient hybrid production technique is proposed. Hybrid production combines the advantages of coil and permanent magnet production; the main magnetic field is generated by permanent magnets, and the regulating magnetic field is generated by coils in parallel. Accordingly, a prototype of a 600-W hybrid-produced magnetic field Hall thruster, HPHT-600, was designed and tested. The HPHT-600 has a small size (channel outer diameter 54 mm), light weight (1.2 kg), low area–volume ratio (0.148), and low magnetic power. In addition, it exhibits a power envelope of 300–1000 W and a total efficiency of 53.5 % at the discharge voltage of 300 V, anode volume flow rate of 35 sccm, and total specific impulse of 1900 s at 500 V and 20 sccm.

Improving the performance of room temperature rotary magnetic refrigerators via magnet shape optimization

A magnetic structure intended for use in a room-temperature rotary active magnetic regenerator (AMR) is presented, under construction at the University of Genoa. Given the overall size of the regenerator and the thickness of the gap, the magnet design is optimized to produce the highest possible magnetic field difference between two adjacent regions. Magnet shape optimization is obtained by introducing a geometry with four degrees of freedom corresponding to the position of the edges of each magnet, plus the remanence angle. This approach serves two main purposes: the primary is to increase the magnetic induction and, to follow, some effort is made to minimize the volume and weight of the expensive NdFeB magnets, while preserving the cooling performance. So, a balance between these two goals must be achieved. After a rough preliminary sizing, a parametric investigation is performed toward these targets and some shapes are presented. The magnetic flux density in the gap, and other consolidated and novel performance indices, are evaluated and compared to those found in the literature for similar devices. The final design achieves, in the air gap, a maximum induction value of 1.045 T, and an average flux density of 0.83 T in a volume per unit length of 0.00268 m3/m in the high induction region. This is accomplished by using 0.00606 m3/m of magnetic material (N50, NdFeB). The magnet designs presented here exhibit a well-balanced performance (in terms of greater cooling for the same magnet weight) compared to earlier designs for similar AMR devices.

Research and Design of the RF Cavity for an 11 MeV Superconducting Cyclotron

In contrast to the room temperature cyclotron, the superconducting cyclotron’s high operational magnetic field and small extraction radius lead to a magnet design with a reduced radius. This limits the space available for the RF cavity in the 11 MeV superconducting cyclotron, necessitating a more compact RF cavity design. By using the transmission line theory, the complex structure of the quarter-wavelength coaxial cavity can be represented as a microwave circuit. Through relevant theoretical analytical formulas, equivalent circuit parameters can be derived. The resonant frequency of the RF cavity is then determined using the equivalent circuit method. The optimization of the RF cavity structure was achieved by creating a numerical model and conducting finite element numerical calculations on the high-frequency resonant system. The comparative results between the equivalent circuit and numerical calculations indicate that the frequency error remains within 0.1%, validating the compact RF cavity design. A multiple linear regression analysis facilitates the prediction of resonance frequency across various parameter variables. By analyzing the fitting formula, RF cavity machining error requirements are established, ensuring a prediction error within 1%, thus meeting engineering design criteria.

Development of a novel flattened magnetron for household microwave oven

This paper presents a design scheme of a Novel Flattened Magnetron for Household Microwave Oven, which makes a breakthrough in the magnetic circuit of the existing magnetron and adopts the symmetrical enhanced magnetic circuit design scheme. Magnetron width has been successfully reduced from 80 mm to 50 mm. The reduction is up to 37.5%. Based on the size of the flattened magnetic circuit system, the theory of magnetron noise, and the knowledge of LC low-pass filters, a filtering structure for the flattened magnetron is proposed. Electromagnetic simulation shows that the magnetron with the new magnetic circuit structure can still meet the design specifications of the magnetron used in the existing microwave oven. An experiment was conducted to verify the proposed design's performance, and it was found to be similar to the existing conventional magnetron.

A novel cost-effective power supply model for industrial appliances based on triangular magnetic shunt transformer design

This paper presents a new design of a magnetic shunt transformer for use in industrial microwave generators. The proposed transformer has a triangular shape and offers several advantages over existing transformer designs, including reduced volume and maintenance costs. We provide a detailed analysis of the transformer's dimensions and an equivalent model of the three-phase high voltage power supply system. The results of this study have significant implications for the field of industrial microwave generator design and could lead to the development of more efficient and costeffective systems. The resulting model is comprised of saturable inductors capable of accounting for the non-linear phenomena of saturation. The power supply is simulated using MATLAB/Simulink with a neuro-fuzzy ANFIS approach. The results are compared to experimental validations of a single-phase reference power supply for a magnetron, validating the proposed power supply. Additionally, the simulation results demonstrate the effectiveness of the proposed design, which outperforms existing transformers in terms of volume, energy efficiency and maintenance costs.

MOLLER Spectrometer Magnet Design With Measured Mechanical Properties of Irradiated S2-Glass Reinforced Cyanate Ester Resin at Elevated Temperature

MOLLER Spectrometer Magnet Design With Measured Mechanical Properties of Irradiated S2-Glass Reinforced Cyanate Ester Resin at Elevated Temperature

Magnetic Design and Electromagnetic Field Simulation of Downhole Turbine Generator

With the increasing difficulty of oil and gas resources exploration and the increase of drilling operations in complex geological environments, the challenges faced by oil drilling operations are also increasing. With the continuous improvement of the intelligence of MWD/LWD drilling technology and downhole instruments, the demand for electric energy is also increasing. In order to ensure the normal operation of the equipment and the accurate acquisition of data, this paper designs a new type of external rotor downhole turbine generator, and designs the structure and parameters of the turbine generator. Finally, Ansoft Maxwell software is used to simulate and analyze the electromagnetic field of the generator. The results show that the induced electromotive force and load current waveform obtained by electromagnetic field simulation analysis have good sinusoidality. At the rated speed of 2500rpm, the effective value of the output line voltage of the turbine generator is about 49.1V, the effective value of the line current is about 10.99A, and the output power is about 841.17W, which meets the design requirements. The research has certain guiding significance for practical engineering.

Analysis of comprehensive magnetic shielding and optimization design of high-conductive layers in magnetic shielding devices for atomic magnetometer

Since the frequency of the biological magnetic field is DC to 500 Hz, it is important to improve the ability of the magnetic shielding device within this range for the measurement of the biological magnetic field and the reduction of the magnetic noise of the SERF magnetometer. At present, the optimization of AC magnetic field shielding in the frequency range of 0.01 to 500 Hz is rarely considered. To optimize the AC shielding factor, this paper analyzed the influence of the position and structure of the high-conductive layer in the magnetic shielding device and proposed an optimized structure of the high conductive layer. What’s more, the theoretical formula was improved by introducing frequency coefficients, solving the problem of significant differences between theoretical calculation results, FEM results and measurement results. Finally, it was verified by experiments that the optimized high-conductivity layer structure can improve the AC shielding factor of magnetic shielding device.

Artificial Intelligence-Powered Pulse Sequences in Nuclear Magnetic Resonance and Magnetic Resonance Imaging: Historical Trends, Current Innovations and Perspectives

This review article explores the historical background and recent advances in the application of artificial intelligence (AI) in the development of radiofrequency pulses and pulse sequences in nuclear magnetic resonance spectroscopy (NMR) and imaging (MRI). The introduction of AI into this field, which traces back to the late 1970s, has recently witnessed remarkable progress, leading to the design of specialized frameworks and software solutions such as DeepRF, MRzero, and GENETICS-AI. Through an analysis of literature and case studies, this review tracks the transformation of AI-driven pulse design from initial proof-of-concept studies to comprehensive scientific programs, shedding light on the potential implications for the broader NMR and MRI communities. The fusion of artificial intelligence and magnetic resonance pulse design stands as a promising frontier in spectroscopy and imaging, offering innovative enhancements in data acquisition, analysis, and interpretation across diverse scientific domains.

Bio-Hybrid Magnetic Robots: From Bioengineering to Targeted Therapy.

Magnetic robots possess an innate ability to navigate through hard-to-reach cavities in the human body, making them promising tools for diagnosing and treating diseases minimally invasively. Despite significant advances, the development of robots with desirable locomotion and full biocompatibility under harsh physiological conditions remains challenging, which put forward new requirements for magnetic robots' design and material synthesis. Compared to robots that are synthesized with inorganic materials, natural organisms like cells, bacteria or other microalgae exhibit ideal properties for in vivo applications, such as biocompatibility, deformability, auto-fluorescence, and self-propulsion, as well as easy for functional therapeutics engineering. In the process, these organisms can provide autonomous propulsion in biological fluids or external magnetic fields, while retaining their functionalities with integrating artificial robots, thus aiding targeted therapeutic delivery. This kind of robotics is named bio-hybrid magnetic robotics, and in this mini-review, recent progress including their design, engineering and potential for therapeutics delivery will be discussed. Additionally, the historical context and prominent examples will be introduced, and the complexities, potential pitfalls, and opportunities associated with bio-hybrid magnetic robotics will be discussed.

Research on magnetic influence factors and optimal design of wall-climbing robot

The adsorption stability and motion flexibility are one of the core problems restricting the development of wall-climbing robots. In order to solve the problem of wall-climbing robots, the basic structure of magnetic adsorption unit is introduced in detail. Secondly, the finite element analysis software was used to optimize the simulation of the relationship between the parameters of the magnetic adsorption unit and the magnetic adsorption force through the control variable method. After optimization, the magnetic adsorption force of the magnetic adsorption unit was significantly improved under the condition that its own volume was unchanged. Finally, the experiment is carried out to verify.

Optimization design of a new hybrid magnetic circuit motor

The combination of permanent magnets and electrically excited windings creates an air gap magnetic field. The development of a hybrid magnetic circuit motor with an adjustable magnetic field is of great significance. This article introduces a hybrid magnetic circuit motor design that combines salient pole electromagnetic and permanent magnets. A tubular magnetic barrier has been designed to reduce inter-pole leakage and enhance the usage rate of permanent magnets in the hybrid magnetic circuit motor. The optimum eccentricity of the rotor has been accurately designed, resulting in an improved sinusoidal distribution of the air gap magnetic density waveform. An analysis of the static composite magnetic field under various excitation currents has been conducted, showcasing the capability of the hybrid magnetic circuit motor to stably adjust the air gap flux density level and output torque. A prototype has undergone comprehensive trial production and testing, conclusively confirming the machine’s superior output performance.

MagGen: A Graph-Aided Deep Generative Model for Inverse Design of Permanent Magnets.

A deep generative model based on a variational autoencoder (VAE), conditioned simultaneously by two target properties, is developed to inverse design stable magnetic materials. The structure of the physics-informed, property embedded latent space of the model is analyzed using graph theory. An impressive ∼96% of the generated materials are found to satisfy the target properties as per predictions from the target-learning branches. This is a huge improvement over approaches that do not condition the VAE latent space by target properties or that do not consider the connectivity of the parent materials from which the new materials are generated. This impressive feat is achieved by using a simple real-space-only representation that can be directly read from material cif files. Model predictions are finally validated by density functional theory calculations on a randomly chosen subset of materials. The performance of the present model is comparable or superior to that of models reported earlier. This model (MagGen) is applied to the problem of designing rare earth-free permanent magnets with promising results.

An Intelligent Optimized Control System for Induction Heating Application

In the modern era, induction heating (IH) technology is utilized for industrial functions like medical applications and domestic applications. Furthermore, efficient uses such as control topologies, magnetic component design, and power electronics have high demand as well as cost-effective with respect to advanced technology. However, IH technology directly targets the power converter and coil so it has wasted higher amount of heat. Also, high power dissipation in an IH system leads to high energy costs and reduced system performance. Hence, various approaches are developed to minimize power dissipation. However, they cannot reduce power dissipation in the induction coil. Thus, a novel Decision-based Squirrel Control System was developed in this article to decrease the power wastage in induction coil optimally. The developed model’s squirrel fitness function monitors power wastage and compensates them by tuning it. The developed model is executed in MATLAB/Simulink, and the results are determined. In terms of rising time, settling time, overshoot, and error rate. Here, the proposed work can achieve 0.075s resting time, 1.02s settling time, 0.05s overshoot, and 0.29% of error rate. The comparative assessment proves that the presented approach attained better results than others.