Numerical study and design optimization of electromagnetic energy harvesters integrated with flexible magnetic materials

윤상원 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.5

This study presents a new design of an electromagnetic energy harvester integrated with a soft magnetic material. The harvester design optimizes the magnetic material characteristics and the size of a rectangular permanent magnet. The design employs a complete magnetic circuit made of (1) a thin-film soft magnetic material that facilitates a flexible but highly (magnetically) permeable beam and (2) an optimally-sized magnet that maximizes the harvester performance. The design is demonstrated to reduce magnetic flux leakage, and thus considerably enhances both magnetic flux density (B) and its change by time (dB/dt), which both influence harvester performance. The improvement in harvester performances strongly depends on critical design parameters, especially, the magnet size and characteristics of magnetic materials, including permeability, stiffness, and thickness. The analyses conclude that recently-introduced nanomaterials (having ultrahigh magnetic permeability) can potentially innovate harvester performances. However, the performance may be degraded without design optimization. Once optimized, the integrated nanomaterials facilitate a significant improvement compared with a conventional design without integrated magnetic materials.

A COMPARATIVE STUDY ON THE DISLODGING FORCE OF MAGNETIC ATTACHMENT TO THE DENTURE RESIN BY MAGNETIC DESIGN AND FIXING MATERIALS

Lee, Jung-Hwa,Lee, Jong-Hyuk,Cho, In-Ho The Korean Academy of Prosthodonitics 2008 대한치과보철학회지 Vol.46 No.3

STATEMENT OF PROBLEM: Detachment of the magnetic assembly from the denture base has been a problem in magnetic overdenture patients. PURPOSE: The objectives of this study were to compare the dislodging force by the fixing materials and the designs of the magnetic assembly, and to compare the effect between the fixing materials and the designs of the magnetic assembly. MATERIAL AND METHODS: Two fixing materials, Jet denture repair $acrylic^{(R)}$ and Super-$Bond^{(R)}$ C&$B^{(R)}$ and two types of magnetic assembly designed with or without wing were used. Each magnetic assembly was fixed in the chamber of the denture base resin block ($Lucitone^{(R)}$199) with each fixing material respectively. These specimens were thermocycled 2,000 cycles in the water held at $4^{\circ}C$ and $60^{\circ}C$ with a dwell time of 1 min each time. Each specimen was seated in a testing jig and then a push-out test was performed with a universal testing machine at a cross head speed of 0.5 mm/min to measure the maximum dislodging forces. RESULTS: Comparing the fixing materials, Super-Bond C&$B^{(R)}$ showed superior dislodging force than Jet denture repair $acrylic^{(R)}$. Comparing the design of the magnetic assemblies, the wing design magnetic assembly showed better dislodging force. Combination of the Super-Bond C&$B^{(R)}$ as a fixing material and wing design magnetic assembly revealed a greatest dislodging force. The kind of fixing material was more influential than the type of magnetic assembly. CONCLUSION: The dislodging force of Super-Bond C&$B^{(R)}$ was significantly higher than Jet denture repair $acrylic^{(R)}$. And the dislodging force of magnetic assembly which have wing design was significantly higher than magnetic assembly which have no wing design.

Novel Design and Research for a High-retaining-force, Bi-directional, Electromagnetic Valve Actuator with Double-layer Permanent Magnets

You Jiaxin,Zhang Kun,Zhu Zhengwei,Liang Huimin 한국자기학회 2016 Journal of Magnetics Vol.21 No.1

To increase the retaining force, a novel design for a concentric, bi-directional, electromagnetic valve actuator that contains double-layer permanent magnets is presented in this paper. To analyze the retaining-force change caused by the magnets, an equivalent magnetic circuit (EMC) model is established, while the EMC circuit of a double-layer permanent-magnet valve actuator (DLMVA) is also designed. Based on a 3D finite element method (FEM), the calculation model is built for the optimization of the key DLMVA parameters, and the valve-actuator optimization results are adopted for the improvement of the DLMVA design. A prototype actuator is manufactured, and the corresponding test results show that the actuator satisfies the requirements of a high retaining force under a volume limitation; furthermore, the design of the permanent magnets in the DLMVA allow for the attainment of both a high initial output force and a retaining force of more than 100 N.

Review on Magnetic Components

Nor Zaihar Yahaya,Mumtaj Begam Kassim Raethar,Mohammad Awan 전력전자학회 2009 JOURNAL OF POWER ELECTRONICS Vol.9 No.2

When converters operate in megahertz range, the passive components and magnetic devices generate high losses. However, the eddy current issues and choices of magnetic cores significantly affect on the design stage. Apart from that, the components’ reduction, miniaturization technique and frequency scaling are required as well as improvement in thermal capability, integration technique, circuit topologies and PCB layout optimization. In transformer design, the winding and core losses give great attention to the design stage. From simulation work, it is found that E-25066 material manufactured by AVX could be the most suitable core for high frequency transformer design. By employing planar geometry topology, the material can generate significant power loss savings of more than 67% compared to other materials studied in this work. Furthermore, young researchers can use this information to develop new approaches based on concepts, issues and methodology in the design of magnetic components for high frequency applications.

Analysis of Linear Machine by Parameter Study using Equivalent Magnetic Circuit and FEA

Sungin Jeong 한국자기학회 2022 Journal of Magnetics Vol.27 No.1

This study proposes an analytical approach by optimum process that is generalized by number of phases, magnet, and pole-pair of linear machines based on a physical magnetic circuit model. The linear machine increases the force output of the machine due to generation of the magnetic field created by the armature winding. There is a strong attractive force between the iron-core armature and the permanent magnet. Therefore, this paper deals not only with one-phase systems by the number of magnet and pole pairs but also two-phase machines in linear machines. All this is carried out for optimum process using geometric parameters based on analytical electromagnetic field research. The best structure for optimum design is selected by a parameter study and it is accomplished with 2-D finite element analysis. The object function and design variables for this parameter study by constraints are chosen for practical and effective design of the machine. Eventually, it suggests new design rules based on optimal design through parameter study. The proposed methods allow us to draw a very important design rule, as a result it can be provided to less time of the machine design and analysis.

Reliability-based robust design optimization for torque ripple reduction considering manufacturing uncertainty of interior permanent magnet synchronous motor

Gyeong Uk Jang,김창완,Dae-Sung Bae,Younghoon Cho,이정종,조승현 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.3

This study performed reliability-based robust design optimization (RBRDO) of stator and rotor shape of the IPM type electric motor to reduce the torque ripple considering uncertainties. A metamodel based on the design of experiments results, which was calculated by using 2-D electromagnetic finite element analysis, was used to calculate manufacturing uncertainties and material property distribution. As a result, the mean torque ripple of the optimum electric motor design was reduced by 56.4 % and the robustness was increased by 61.8 % compared with the initial design. The RBRDO design was compared with the designs of deterministic design optimization and reliability-based design optimization, and it was shown that, by using the RBRDO method, the optimum IPMSM can be designed to satisfying not only the minimum torque ripple but also the robustness and the reliability of output torque and torque ripple.

Optimal Rotor Design of IPM Motor for Improving Torque Performance Considering Thermal Demagnetization of Magnet

Sunghoon Lim,Seungjae Min,Jung-Pyo Hong IEEE 2015 IEEE transactions on magnetics Vol.51 No.3

<P>This paper proposes a new design technique for improving torque performance of interior permanent magnet (IPM) motors with consideration of the thermal characteristic of magnet. To verify the driving performance of IPM motor at operating temperature, a magnetic-thermal coupled analysis was performed with a heat source, such as iron loss and copper loss, and the thermal characteristics of permanent magnet (PM) is considered to define the magnetic property. The optimization problem is formulated to minimize the harmonics of magnetic flux, which cause iron loss, as well as to maximize the output torque for satisfying the design target. To obtain an optimal rotor shape of the IPM motor, which is composed of both PM and ferromagnetic material, a multi-phase level set model is employed for representing the precise boundaries of the magnetic materials. A design example of a motor with Nd-Fe-B magnet, which has a tendency to be demagnetized at high temperature, is provided to verify the effectiveness of the proposed method.</P>

Multilayer Piezoelectric Transducer Design Guidelines for Low Profile Magnetic-less DC/DC Converter

Gab-Su Seo,Bo-Hyung Cho 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

In this paper, multilayer piezoelectric transducer design guidelines are presented for a low profile magnetic-less DC/DC converter. Power capacity considerations are very important in designing magneticless power converters with piezoelectric devices, as it has different characteristics from conventional power devices such as magnetic inductors and transformers. Piezoelectric devices have fundamental limitations on power handling, such as maximum operation voltage and current capacity. Using an electro-mechanically coupled equivalent circuit model of a piezoelectric element, the power capacity is discussed and the current capacity equations, including material constants, are derived. In addition, benefits and trade-offs of a multilayer structure application to improve power capacity of piezoelectric transducers are discussed and design considerations for a piezoelectric power application are given. Customized piezoelectric transducers can be designed based on the design guidelines to meet system requirements. Experimental results with a 15W prototype magnetic-less DC-DC converter using a multilayered piezoelectric transducer verify the feasibility of the research.

Magnet Design of a Proton and Carbon-ion Synchrotron for Cancer Therapy

Hyung-Suck Suh,Young-Gyu Jung,Heung-Sik Kang 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.56 No.61

The magnets for a medical synchrotron for cancer therapy with proton and carbon-iron beams were designed. The synchrotron components are the magnetic septa, electrostatic septa, betatron core, and conventional magnets. This design was carried out to satisfy the physics requirements from the beam dynamics. We used a 3D code for the electromagnetic simulation and the optimization of the magnetic structures. In this paper, the basic design process for the electromagnetic devices will be described.

원형무코일로 구성된 MRI용 초전도 자석의 설계와 비교

김용권(Yong-Gwon Kim),현정호(Jung-Ho Hyun),서증훈(Jeung-Hoon Seo),김혁기(Hyug-Gi Kim),오창현(Chang-Hyun Oh) 大韓電子工學會 2011 電子工學會論文誌-SC (System and control) Vol.48 No.6

본 논문에서는 초전도 자석의 자장 균일도를 개선하기 위한 방법으로 3가지 형태의 magnet 모델을 제안하고 각각의 자석형태에 대하여 같은 세기의 자장을 (Magnet field strength) 가질 경우에 최소전력 방식으로 최적화된 전류 분포에 해당하는 coil wire의 길이 그리고 해당 조건에서의 자장의 불균일도를 시뮬레이션을 통하여 비교 분석하였다. 구성된 3가지 magnet type을 동일한 조건 (계산 점의 개수 18개 20㎝ DSV)에 대해서 wire길이와 main field inhomogeneity를 비교하였으며 이러한 시뮬레이션 결과를 통하여 얻을 수 있는 결론은 계산점의 수가 적을수록 wire의 길이는 짧아지나 field inhomogeneity는 높아진다는 것이다. 즉 Magnet shim을 수행할 경우 계산점을 줄이는 방법으로는 짧은 wire의 길이와 main field homogeneity를 동시에 만족하도록 최적화 하는 것이 거의 불가능함을 의미하는 것이다. 그러나 DSV를 줄였을 경우에 계산점을 줄였을 때에 비해 우수한 결과 값을 얻을 수 있었다. 결론적으로 공간적으로 개방되어 있는 magnet model의 경우 계산점을 줄여 shimming을 진행할 경우 동일한 imaging region의 크기에 대해 더 많은 전류(또는 wire 길이)가 필요하고 field 균일도도 떨어졌으나 작은 ROI를 대상으로 영상을 얻는 경우 유용하게 사용될 수 있다. This paper proposed a method which is the three types of magnet model for improving field inhomogeneity of superconducting magnet. The length of coil wire was compared for the optimized current pattern using minimum power methods and field inhomogeneity under the specific simulation condition in case of same magnet field strength about each magnet type field inhomogeneity. Length of wire and field inhomogeneity were compared under the same condition(18 target points 20㎝ DSV). According to the simulation results the smaller target points can reduce the wire length but it can not improve the field inhomogeneity. Length of wire and low field inhomogeneity can not improve in same time. However small DSV and reducing target points can overcome the these problem. And to conclude if it processes shimming as reducing target points in case of magnet model which is open to space about the size of same imaging region it needs a lot of current values( or the length of wire) and decreases field homogeneity but it is useful to get small ROI.