• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.14 no.11
• /
• pp.1147-1152
• /
• 2004

The objective of this work is to develop a new design method to find optimal coils, especially the optimal coil configuration of an optical pickup actuator. In designing actuator coils, the developed Lorenz force in the coils along the desired direction should be made as large as possible while forces and torques in other directions should be made as small as possible. The design methodology we are developing is a systematic approach that can generate optimal coil configurations for given permanent magnet configurations. To consider the best coil configuration among all feasible coil configurations, we formulate the design problem as a topology optimization of a coil. The present formulation for coil design is noble in the sense that the existing topology optimization is mainly concerned with the design of yokes and permanent magnets and that the optimization of actuator coils is so far limited within shape or size optimization. Though the present design methodology applies to any problem, the specific design example considered is the design of fine-pattern tracking and focusing coils.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.26 no.4
• /
• pp.389-396
• /
• 2015

A coil design of pulse induction metal detectors has been described. The search coil was demonstrated by using the wire with the diameter of 0.3 mm, 0.5 mm and 1.0 mm and the dielectric plate with the $30cm{\times}30cm$ and $35cm{\times}35cm$, the time constant and the currents of the coil as the variation of the coil size and the number of coil turns was characterized. The coil parameters like the resistance, the inductance and the time constants as the variation of the diameter of the wire, the coil size and the number of coil turns were compared and analysed through the calculation and the measurement. In addition, investigating the coil currents as the variation of the input pulse width, the coil design of pulse induction metal detectors has been discussed.

• Progress in Superconductivity and Cryogenics
• /
• v.14 no.4
• /
• pp.36-40
• /
• 2012

This paper presents an experimental and numerical study on current limiting characteristics of a fault current controller (FCC). The FCC consists of an AC/DC power converter, a superconducting coil, and a control unit. Even though some previous researches proved that the FCC could adjust the fault current level, the current limiting characteristics by the superconducting coil should be investigated for design of the coil. In this paper, four kinds of model coils were tested; 1) air core, 2) iron core without any bias, 3) reversely magnetized core (RMC) using permanent magnets, and 4) RMC using an electromagnet. Based on a comparative study, it is confirmed that a RMC by an electromagnet (EM) could increase the effective inductance of the coil. In this paper, a numerical code to simulate the HTS coil with RMC was developed. This code can be applied to design the HTS coil with active reversely magnetized bias coil.

• Transactions of Materials Processing
• /
• v.23 no.7
• /
• pp.431-438
• /
• 2014

For electromagnetic forming(EMF) the most important feature is a forming coil which creates the electromagnetic force(Lorentz force), using current density and a magnetic field. Most previous papers have concentrated on the final configuration of the blank or the efficiency of EMF process. Studies focused on the design parameters affected by the forming coil performance have not been conducted. In order to design a suitable forming coil for an object, the current study uses LS-DYNA EM-Module to not only optimize the coil but also to examine the effect of coil performance. By this method a suitable forming coil was made and tested to determine whether or not good formability was achieved in a free bulge test Numerical analysis was also used. The workpiece was Al 1100-O with a thickness of 1.27mm and the coil was made from copper CW004A, which has good electrical conductivity and is suitable for electrical components.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.53 no.8
• /
• pp.477-487
• /
• 2004

Helical magneto-cumulative generators(MCGs) are devices which convert explosive energy into electromagnetic energy. The electromagnetic energy supplied from an external circuit is amplified by an explosively driven metal conductor mounted at the center of a helical coil compressing magnetic flux between the conductor and the coil. To optimize the coil design, output properties of small-size helical MCGs were measured while varying design parameters; the number of coil sections, length of the sections, pitch in the sections, and type of copper wire. Dimensions of the coil were kept constant, 50 mm in diameter and 200 mm in length. The coil was fabricated by using enamel-coated copper wire of 1 mm in diameter. The highest energy amplification ratio and figure of merit were 52.5 and 0.81, respectively. from an helical MCG with initial inductance of 63.7 $\mu$H at initial energy of 0.152 kJ Based on the experimental and calculated results, empirical formulas capable of optimizing coil designs were derived. By using these formulas, pitch in each coil section can be obtained at an arbitrary inductive load for high energy amplification ratio and figure of merit.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.21 no.4
• /
• pp.356-363
• /
• 2016

The design methodology of an adequate input voltage and magnetizing inductance to minimize reactive power is suggested to design a wireless power transfer (WPT) converter for high-power transfer efficiency. To increase the magnetizing inductance, the turn number of the WPT coil is increased, thus causing high parasitic resistance in the WPT coil. Moreover, the high coil resistance produces high conduction loss in the transfer and receive coils. Therefore, the analysis of conduction loss is used in the design of the WPT coil and the operating point of the WPT converter. To verify the proposed design methodology, the mathematical analysis of the conduction loss is presented by experimental results.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 1999.03b
• /
• pp.195-198
• /
• 1999

For the thixoforming process beside an existing solidus-liquidus interval, the reheating conditions to obtain the globular microstructure are very important. It relies on the control of globular microstructure of semi-solid alloys that contain non-dendritic particles. To obtain the globular microstructure in cross section of billet, the optimal design of the induction coil is necessary. Therefore, in this paper the optimal coil design to minimize electromagnetic end effect will be proposed. The results of coil design were also applied to the reheating process to obtain a fine globular microstructure. Finally, reheating data base of aluminum alloys for thixoforming and FEM model for induction heating based on the optimal coil design have been proposed.

• Proceedings of the Korean Society of Laser Processing Conference
• /
• 2006.06a
• /
• pp.129-134
• /
• 2006

In this paper, actuator based on voice coil motor is designed and estimated to check the capability whether that system is in design specification or not. Design specification is moving range as $20{\times}20mm^2$ a along XY-axis in plane and maximizes bandwidth for high speed. The type of voice coil motor is selected with regarding design specification and minimizes the size of actuator. Flux density of designed voice coil motor is simulated. And PI controller is designed to maximize bandwidth of actuator. Finally, characteristic of designed actuator is simulated and that result reveals the validity of presented design.

• Progress in Superconductivity and Cryogenics
• /
• v.7 no.3
• /
• pp.21-28
• /
• 2005

Superconducting synchronous motors and generators have the field coil composed of superconductor with almost zero resistance at superconducting state. Therefore, copper loss at the conventional field coil is eliminated and the superconducting machine gets higher efficiency. The armature coil of the superconducting machine is composed of copper wire and supported by non-magnetic material such as FRP (Fiber Reinforced Plastic) This paper contains the design Procedure of a 1MW superconducting synchronous motor using high-temperature superconductor only for the field coil. Especially, the armature coil is designed by water-cooling in order to dissipate Joule heat easily. Moreover, 3-dimensional electromagnetic design is conducted to get a proper design result and reduce design errors from 2-dimensional approach.

• Proceedings of the KIEE Conference
• /
• 2011.07a
• /
• pp.11-12
• /
• 2011

In electromagnetic coupled resonance(ECR) WPT system, the main key for wireless power transmission is the design method of the ECR coils. The ECR coils is classified to the helical coil(3D) type and the spiral coil(2D) type as a coil structure. The pattern of the spiral coil type has been studied in favor of commercialization. In this paper, the design characteristics of the helical coil and the spiral coil is considered using a Vector Network Analyzer. It is analyzed according to the distance of coupling coefficient between the ECR coils. Also, It is analyzed for the relationships such as the maximum transmission efficiency and the resonant frequency depending on the distance between the coils.