International Journal of Applied Electromagnetics and Mechanics - Volume 55, issue S1

Authors: Zhu, Lixun | Yoon, Hee-Sung | Koh, Chang-Seop

Article Type: Research Article

Abstract: Magnetostriction in highly Grain-oriented electrical steel sheet (ESS) is a primary source of vibration and acoustic noise of power transformers at no-load condition. Especially rotating magnetization, as it occurs in joint area of three-phase power transformer, makes the magnetostriction bigger and more complex than that under alternating magnetization. Meanwhile, magnetic flux density along transverse direction makes a lot bigger magnetostriction than that under rolling direction. In this paper, a new measuring system of the magnetostriction are developed for a highly Grain-oriented electric steel sheet (HGO-ESS) of which magnetic domains are bigger in size and higher in degree of alignment than …those of a Grain-oriented one. The magnetostriction characteristics of some HGO-ESS are measured by using the developed system under both alternating and rotating magnetic fields. An improved magnetostriction model is also proposed based on the mechanical elasticity, and its effectiveness is validated through comparisons with experimentally measured results from the measuring system. Show more

Keywords: Electrical steel sheet, magnetostriction, magnetostriction force, transformer

DOI: 10.3233/JAE-172261

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. S1, pp. 87-96, 2017

Authors: Kimura, Yusuke | Takahashi, Yasuhito | Fujiwara, Koji

Article Type: Research Article

Abstract: Although two-dimensional (2-D) magnetic properties can be measured by using a 2-D single sheet tester (SST), the construction of the reliable 2-D SST is considerably difficult. By contrast, the flux density and magnetic field parallel to the excitation direction can be measured in a normal one-dimensional (1-D) SST. If the average flux density points toward the excitation direction in a specimen with any inclination angle from its rolling direction, the magnetic energy can be defined and therefore 2-D magnetic properties can be calculated by means of an energy-based modelling method. However, the direction of the flux density and magnetic field …in the 1-D SST has not been deeply discussed when a specimen with any inclination angle is measured. In this paper, the behavior of the flux density and the magnetic field strength is examined by using 1-D SST. The direction of the flux density is measured by using a pair of cross B-coils. The direction of the magnetic field strength is measured by using a pair of cross H-coils. The effect of the specimen width on the distribution of flux density is also investigated by using a magnetic field analysis. As a result, when a pair of cross H-coils is adopted to a specimen with appropriate aspect ratio, 2-D magnetic properties can be measured by means of the 1-D SST. Show more

Keywords: 2-D magnetic properties, single sheet tester, longitudinal direction

DOI: 10.3233/JAE-172262

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. S1, pp. 97-104, 2017

Authors: Ferrara, Enzo | Appino, Carlo | Rocchino, Luciano | Ragusa, Carlo | de la Barrière, Olivier | Fiorillo, Fausto

Article Type: Research Article

Abstract: The magnetic power losses have been measured at 50 Hz and different peak polarization values on different types of non-oriented and grain-oriented Fe-Si sheets using the Epstein frame, according to the current standards. The very same measurements have then been repeated by measuring polarization and tangential magnetic field by means of localized windings, centrally placed on the strips inside the Epstein frame windings, thereby retrieving the effective field and the true power loss figure. It is obtained that the ratio of the standard P 𝑒𝑝𝑠𝑡 to the effective P 𝑒𝑓𝑓 loss figure, …which can be interpreted in terms of ratio of effective l 𝑒𝑓𝑓 to conventional (l m = 0.94 m) magnetic path length, evolves with the peak polarization J p , showing, in general, a monotonic increase with increasing J p . The deviation of P 𝑒𝑝𝑠𝑡 from P 𝑒𝑓𝑓 is observed to range from about - 3% in the non-oriented alloys at low inductions to about + 5% in the grain-oriented alloys at J p = 1.8 T. This behavior finds a rationale in the existence of a polarization profile J p ⁢ ( x ) measured along the strip length and in the dependence of P 𝑒𝑓𝑓 on J p , showing a power law P 𝑒𝑓𝑓 ⁢ ( J p ) ∝ J p n , with n > 1 and increasing with J p . The so calculated effective path length l e ⁢ f ⁢ f = l m ⋅ P 𝑒𝑝𝑠𝑡 /P 𝑒𝑓𝑓 consistently shows a monotonic increase with J p , which is more relevant in the GO alloys. Show more

Keywords: Magnetic power losses, Epstein frame, magnetic steels

DOI: 10.3233/JAE-172263

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. S1, pp. 105-112, 2017

Authors: Hou, Ruifen | Sievert, Johannes | He, Jian | Lin, Anli

Article Type: Research Article

Abstract: The van-der-Pauw (VDP) method and the traditional measurement method are used to measure the resistivity of the electrical steel plate and strip samples. According to the comparison of the two methods, the relative difference between them is 0.27% for sample of g-o-material and 0.06% for that of n-o-material. The uncertainty of the two methods both are 0.31%. It can be stated that the two methods, the VDP and the traditional method, applied to strip samples, show excellent agreement and should be introduced both in the new edition of the IEC 60404-13 standard.

Keywords: Van-der-Pauw, resistivity, electrical steel, 4-terminal method

DOI: 10.3233/JAE-172264

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. S1, pp. 113-118, 2017

Authors: Le, Minhhuy | Kim, Jungmin | Yang, Dongcheol | Lee, Heejong | Lee, Jinyi

Article Type: Research Article

Abstract: This paper presents an electromagnetic testing method for the inspection of cracks in an overlay welding area. The overlay welding method is usually used to repair failure welds in a structure in which the components are difficult and expensive to replace. The inspection system uses an air-core exciting coil to produce an electromagnetic field in the overlay welding area and a linearly integrated giant magnetoresistance (GMR) sensor array (LIGiS) to measure the distribution of the electromagnetic field around the cracks; thus, the cracks can be inspected. The LIGiS is fabricated using 32 GMR sensor elements arrayed at 0.6 mm intervals. …Artificial cracks with different sizes, orientations, and locations on the crisp surface of an overlay welding sample are tested to verify the effectiveness of the proposed method. Show more

Keywords: LIGiS, eddy current testing, nondestructive testing, overlay welding

DOI: 10.3233/JAE-172265

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. S1, pp. 119-124, 2017

Authors: Zhao, Xiaojun | Guan, Dawei | Zhang, Honggang | Xiao, Fan | Meng, Fanhui

Article Type: Research Article

Abstract: The measurement of DC magnetic properties of soft magnetic materials is carried out by using the static performance testing system (SPTS). The measured limiting hysteresis loop is used to generate the first-order reversal curves (FORCs), which can be effectively applied to the modeling of hysteretic characteristics and verification of hysteresis model. Consequently measurement of FORCs in experiment is unnecessary, whereas efficiency and accuracy of parameter identification can be guaranteed to enhances the applicability of the Preisach model. The concentric hysteresis loops and high-order reversal curves are simulated by using the H -based Preisach model, and a good agreement …between the measured and simulated results verifies the accuracy and effectiveness of the proposed method. Show more

Keywords: DC magnetic properties, first-order reversal curves, limiting hysteresis loop, Preisach model

DOI: 10.3233/JAE-172266

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. S1, pp. 125-133, 2017

Authors: Li, Wei | Fu, Weinong

Article Type: Research Article

Abstract: Finite element method (FEM) of nonlinear magnetic field computation embedded with different vector Jiles-Atherton (J-A) hysteresis models is investigated in this paper. Newton’s method is adopted to do the nonlinear iteration. Both scalar and vector J-A models are incorporated into the FEM computation. The TEAM workshop problem 32 is used as a numerical example. The computed results are compared with the measured ones, which shows the effectiveness of the developed algorithm. The specifics of different vector J-A models are pointed out from the viewpoints of modelling accuracy and convergence performance.

Keywords: Finite element method, Jiles-Atherton model, Newton’s method, TEAM problem 32

DOI: 10.3233/JAE-172267

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. S1, pp. 135-140, 2017

Authors: Zhu, Lixun | Lim, Jeonghyeok | Koh, Chang-Seop

Article Type: Research Article

Abstract: The hysteresis properties of electrical steel sheet (ESS) is very helpful to develop new type electrical machines and improve their performance. Therefore, two-dimensional steel sheet tester (SST) is required to measure the hysteresis properties of ESS. This paper introduces a kind of square type SST, but this SST can only measure the non-oriented and grain-oriented ESS because the size of the specimen is not large enough. To measure highly grain-oriented ESS, a new round type SST which is designed to have broader region of uniform field and allows a larger specimen is proposed in this paper. Meanwhile, magnetostriction properties also …can be measured by this round type SST. Show more

Keywords: Electrical steel sheet, single sheet tester, hysteresis property, magnetostriction

DOI: 10.3233/JAE-172268

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. S1, pp. 141-146, 2017

Authors: Cheng, Zhiguang | Forghani, Behzad | Wang, Xuegang | Liu, Lanrong | Liu, Tao | Fan, Yana | Zhang, Junjie | Zhao, Xiaojun | Liu, Yang

Article Type: Research Article

Abstract: This paper discusses engineering-oriented magnetic material property modeling, fully taking into account the requirements posed by industrial applications, involving the magnetic properties measured under both standard and extreme conditions, the combination of material modeling and numerical analysis, and the validation of modeling and simulation. It presents some application notes on typical magnetic measurement and modeling, concerning the Epstein combination and data weighted processing method, the additional iron loss caused by 3-D excitation, the examination of magnetic flux inside laminated stacks, and the effect of both B-H curves and solvers on loss analysis, based on the authors’ recent research. In addition, …future research projects on the determination and application of the magnetic material properties, under practical working conditions, are proposed. Show more

Keywords: Magnetic material and component, industrial magnetic measurement, working magnetic property, modeling and simulation, validation and application

DOI: 10.3233/JAE-172269

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. S1, pp. 147-158, 2017

Authors: Zhao, Zhigang | Cheng, Z. | Forghani, B. | Liu, F. | Li, Yongjian | Liu, L.

Article Type: Research Article

Abstract: The modeling and reduction of the iron loss is increasingly concerned in both analysis and design of large electromagnetic devices under today’s extreme excitations. This paper aims to investigate the effective and practical approaches to exactly determine the iron loss inside laminated core under ac-dc hybrid excitation in the numerical analysis, and validate the proposals based on the product-level models.

Keywords: Ac-dc hybrid excitation, magnetic property, measurement and numerical analysis, iron loss

DOI: 10.3233/JAE-172270

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. S1, pp. 159-167, 2017