• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.1
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• pp.311-316
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• 2012

In this paper, chaotic circuit of the Lorentz system for engineering applications was implemented using resistor, multipliers, capacitors and operational amplifiers. The implemented Lorentz chaotic system was analysed by PSPICE program. PSPICE simulation results show many kind of chaotic phenomena such time waveforms and phase plots. Meanwhile, according to resistor's variation, we got that Lorentz system show equilibrium state, periodic state and chaotic state.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.4
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• pp.273-278
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• 2016

In this paper, chaotic circuit of the Lorentz system using multipliers, operational amplifiers, capacitor, fixed resistor and variable resistor for control has been designed in a electronic circuit. Through PSPICE program, electrical characteristics such as time waveforms, frequency spectra and phase attractors analyzed. And in the special area ($10{\sim}100k{\Omega}$) of the $500k{\Omega}$ control variable resistor, the circuit showed chaotic dynamics. Also, we implemented the circuit in a electronic hardware system with discrete elements. Measured results of the circuit coincided with simulated data.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1083-1086
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• 2003

Recently, the study on bearingless motors which integrate both motor and magnetic bearing function in one stator is very active, as many machines have high rotational speed, high precision, smaller size and lighter weight. In this paper, we propose a novel rotary actuator including function of axial bearing using Lorentz force as a preceding research for development of a bearingless motor. As using Lorentz force, this type has some merits such as the linearity of control force, freedom from flux saturation and high efficiency unlike conventional rotary actuators using a reluctance force. This type is cotrolled independently in levitation and rotational directions respectively. It shows by mathematical expression of levitation force and torque in the proposed rotary actuator. And also, the levitation force is generated by magnetic interaction between the magnetic materials and the rotational torque is generated by Lorentz force. Finally. for verification of this proposed system, a prototype is made and some experiments will be performed in the near future.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.11
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• pp.527-532
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• 2005

During the last ten years the new interruption techniques, which use the arc energy itself to increase the pressure inside a chamber by the PTFE nozzle ablation, have displaced the puffer circuit breakers due to reduced driving forces and better maintainability. In this paper, we have investigated the thermal flow characteristics inside a thermal puffer type gas circuit breaker by solving the Wavier-Stokes equations coupled with Maxwell's equations for considering all instabilities effects such as turbulence and Lorentz forces by transient arc plasmas. These relative inexpensive computer simulations might help the engineer research and design the new interrupter in order to downscale and uprating the GIS integral.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.10
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• pp.2589-2595
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• 2009

An electromagnetic pump has been designed using Load Distribution Method and Equivalent Circuit Method, and installed in a liquid metal flow system. The relation between the driving power of he electromagnetic pump and the flow rate was proposed. Also, the flow velocity and flow rate has been calculated by treating the Lorentz force as a source term in the Navier-Stokes equation. The calculation results were analyzed and compared with data from a commercial Code, FLUENT. They agreed well with each other within an error of 5%.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.1348-1354
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• 2015

In this paper, chaotic circuit of the voltage controlled Lorentz system for engineering applications has been designed and implemented in an electronic circuit. The proposed circuit consists of MOS variable resistor, multipliers, capacitors, fixed resistors and operational amplifiers. The circuit was analysed by PSPICE program. PSPICE simulation results show that chaotic dynamics of the circuit can be controlled by the MOS variable resistor through time series analysis, frequency analysis and phase diagrams. Also, we implemented the proposed circuit in an electronic hardware system with discrete elements. Measured results of the circuit showed controllability of the circuit using the MOS resistor.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.11
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• pp.199-207
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• 1998

This paper presents the design and the control of three degree-of-freedom(DOF) fine positioning device based on an electro-magnetic force. The device is designed by use of a magnetic circuit theory and it is capable of fine motion due to the electro-magnetic force. The device consists of permanent magnets, yokes and coils. The magnetic fluxes generated from the permanent magnets constitute magnetic paths through steel, whereas the coils are arranged into the gap between two surfaces of the yokes. Therefore, by supplying current to the coils, the coils are capable of some motions due to Lorentz forces. For the optimal design of the actuating system, the system parameters are defined and investigated under the given constraints. From the system modeling in small displacement, three decoupled equations of motion are obtained. To get better performance of the system, a PID controller is implemented. Experimental results are presented in terms of time response and accuracy.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.6
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• pp.143-149
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• 2008

This paper presents the results of the study on the novel micro mixer. Existing micro mixer is classified as active mixing and passive mixing by the mixing principles. Both mixing principles have problems. For solving these problems, this research has developed the novel micro mixers based on a totally different principle compared with former mixers. They not only have a simpler structure than former ones but also are able to achieve high mixing efficiency in spite of low power consumption due to using Lorentz Force. In addition, they are designed to increase the efficiency of mixing by changing the rotating direction of fluid with a polar switching circuit. Driving forces of the mixer are Lorentz force and a moving force of fluid due to electrophoresis. Because the efficiency of mixer is affected by electrode shape, several models have been made. The computer simulation has been made to estimate the efficiency of each mixer.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.7
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• pp.733-740
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• 2013

The high-velocity electromagnetic forming (EMF) process is based on the Lorentz force and the energy of the magnetic field. The advantages of EMF include improved formability, wrinkle reduction, and non-contact forming. In this study, numerical simulations were conducted to determine the practical parameters for the EMF process. A 2-D axis-symmetric electromagnetic model was used, based on a spiral-type forming coil. In the numerical simulation, an RLC circuit was coupled to the spiral coil to measure various design parameters, such as the system input current and the electromagnetic force. The simulation results show that even though the input peak current levels were at the same level in each case, the forming condition varied due to differences in the frequency of the input current. Thus, the electromagnetic forming force was affected by the input current frequency, which in turn, determined the magnitude of the current density and the magnetic flux density.

• Journal of Magnetics
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• v.21 no.2
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• pp.187-191
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• 2016

Retrieving the equivalent electromagnetic parameters (permittivity and permeability) plays an important role in the research and application of metamaterials. Frequency dispersion of magnetic permeability has been theoretically predicted in a metamaterial composed of cut wire pairs (CWP) separated by dielectric substrate on the basis of circuit theory. Magnetic resonance resulting from antiparallel currents between the CWP is observed at the frequency of minimum reflection loss (corresponding to absorption peak) and effective resonator size can be determined. Having calculated the circuit parameters (inductance L, capacitance C) and resonance frequency from CWP dimension, the frequency dispersion of permeability of Lorentz like magnetic response can be predicted. The simulated resonance frequency and permeability spectra can be explained well on the basis of the circuit theory of an RLC resonator.