We have proposed and demonstrated a fiber optic magnetic field sensor using a FBG (fiber bragg grating) attached on a Terfenol-D bar. The volume of Terfenol-D is changed by the applied magnetic field due to the magnetostriction effect, as a result, the grating period of FBG varies with the intensity of the magnetic field and the Bragg wavelength of FBG is shifted. The temperature sensitivity of the sensor was measured with and without the magnetic field. The temperature sensitivity of the sensor was measured to be 0.02 nm/℃. We observed that the sensitivity of the fabricated device to magnetic field intensity was decreased with the environment temperature.

The internet of things (IoT) technology is a key component for the advent of 4^th industrial revolution, which is the network of home appliances, infrastructures, and vehicles to remotely investigate these systems. For the operation of compact IoT devices, batteries are widely used as electric power, and the limited lifetime of batteries inevitably leads to periodic replacement. Magneto-mechano-electric (MME) generators may be alternatives to batteries inside the IoT devices by converting stray magnetic field into electric energy, since we are always surrounded by ambient alternating current (AC) magnetic fields induced from electric power transmission lines everywhere. This article reviews the recent domestic research progress in high-performance MME generators and their application field for IoT and electronic devices.

Citations

• Magneto-mechano-electric energy harvesting for sustainable IoT and next-generation electronics: Materials strategies, device engineering, and challenges
  Deepak Rajaram Patil, Atul Thakre, Mengdi Fu, Muhammad Waheed, Chang Min Lee, Hyun Jae Lee, Geon Lee, Sagar M. Mane, Seung Yoon Ryu
  Sensors and Actuators A: Physical.2026; 411: 118476.     CrossRef

Commonly, a live-line alarm can be used to measure the electric field strength of a high-voltage system to calculate its current, but it is hard to detect the electric field of shielded cables or concealed structures, such as underground distribution cables. Current sensors can detect the magnetic field in a single core wire, but they cannot determine the magnetic field about a double-core wire because the currents flow in opposite directions. Therefore, it is very difficult to detect certain current problems, such as a fault current in an extension line comprised of a double line. In this paper, to ultimately develop a sensor that can detect the current regardless of line conditions, we used a simulation to determine the concentration of the magnetic field dependent on the distribution of the external magnetic field and the path of each line’s core.

Electrical energy is playing an increasingly vital role as the primary energy source in everyday life. With the increase in electric power consumption, power facilities are under an increasing stress and must operate at a high capacity. Consequently, the demand for electric power cables in power transmission and distribution lines is rapidly increasing. Underground distribution lines have been steadily replacing the aboveground lines owing to the increase in electric power demand and the need to increase the supply voltage. In addition to line damage, worker safety is of primary concern in this type of underground infrastructure.In this study, to improve the safety of workers dealing with underground transmission lines, we analyzed the electromagnetic field generated around the distribution line and determined the basic criteria for developing a device that can detect a live underground line.

Nowadays, it is increasingly important to detect whether cables are live for the operator`s safety if there is a sudden power failure. It is especially hard to detect the electrical field of an underground line because of shielding. This paper on detection of live-line states in cables studied the detection characteristics of the change in the magnetic field and axis as the frequency, voltage, and distance at the same load are changed using 3 axes. A search coil type was used as a magnetic field sensor with non-contact. We found that magnetic fields decrease proportionally to the square of the distance and the decrease of rated voltage with load effected to magnetic field. The magnetic field was detected by 3-axis sensors given correct proximity, but appeared as noise components beyond a distance of 2 cm.

In this research, the development of fabrication technique of bulk YBaCuO superconductors for application was studied. In fluence of BaZrO₃ addition on magnetization characteristics of thermal pyrolysis textured YBaCuO superconductor was investigated. Fine BaZrO₃ particle were dispersed within the textured YBaCuO matrix by means of the thermal pyrolysis processing. Magnetic levitation force for YBaCuO superconductors were obtained using Nd-B-Fe permanent magnet, at 77 K and at the magnetic field from 0 to 5.3 K gauss. In the unadded superconductor and 5 wt% BaZrO₃ addition, anomalous magnetization behavior, which is characterized by the intermediate magnetic field, was observed at 77 K. Critical current density was about few hundreds A/㎠ and the magnetic characteristics increased slightly by addition of BaZrO₃ powder. Maximum magnetic force was obtained in the YBaCuO superconducting bulk with 3 wt.% BaZrO₃ addition.

The magnetoelectric characteristics on layered Ni-PZT-Ni, Co, Fe composites by epoxy bonding for magnetic field sensor were investigated in the low-frequency range. The ME coefficient of Ni-PZT-Ni, Ni-PZT-Co and Ni-PZT-Fe composites reaches a maximum of 200 mV/cm·Oe at Hdc=110 Oe, 106 mV/cm·Oe at Hdc=90 Oe and 87 mV/cm·Oe at Hdc=160 Oe, respectively. A trend of ME charateristics on Ni-PZT-Co, Ni-PZT-Fe composites was similar to that of Ni-PZT-Ni composites. The ME output voltage shows linearly proportional to ac field Hac and is about 0∼150 mV at Hac=0∼7 Oe and f=110 Hz in the typical Ni-PZT-Ni sample. The frequency shift effect due to the load resistance RL shows that the frequency range for magnetic field sensor application can be modulated with appropriate load resistance RL. This sample will allow for a low-magnetic ac field sensor in the low-frequency (near f=110 Hz).

Citations

• Enhanced Self-Biased Magnetoelectric Coupling in Laser-Annealed Pb(Zr,Ti)O3 Thick Film Deposited on Ni Foil
  Haribabu Palneedi, Deepam Maurya, Liwei D. Geng, Hyun-Cheol Song, Geon-Tae Hwang, Mahesh Peddigari, Venkateswarlu Annapureddy, Kyung Song, Yoon Seok Oh, Su-Chul Yang, Yu U. Wang, Shashank Priya, Jungho Ryu
  ACS Applied Materials & Interfaces.2018; 10(13): 11018.     CrossRef

In this paper, it tried to develop the core sensor for detection of micro magnetic field in electric wires. The sensor is non contact type and is consisted of ferrite core for low price. To investigate their properties for variations of current, it changed the number of winding and the length of sample core, it examined, to check the live wire situation in built-in wires, electrical characteristics due to difference between electric wires and core sensor. As the results, it verified live wire situation at the number of winding(5,000) and within length of 6[cm]. Also, it obtained magnetic field magnitude decreased inverse proportion ratio to a square about difference between electric wires and core sensor.

Citations

• Transport Loss Characteristics of the Bi-2223 Tapes in an External AC Magnetic Field
  K. Ryu, H.J. Song, H.J. Kim, K.C. Seong
  IEEE Transactions on Applied Superconductivity.2006; 16(2): 1011.     CrossRef