• Proceedings of the KIEE Conference
• /
• 1999.07a
• /
• pp.121-123
• /
• 1999

The purpose of this paper is to establish a method of design of the Ultrasonic Motor for Driving Robot Hand. This method is based on two models for the ultrasonic motor(a two dimensional elastic contact model. electric equivalent circuit). And analyzed the basic model which installed in the module to match the suitable standard. As varied external diameter, internal diameter and thickness, the proper ultrasonic motor is implemented to find a targeted resonant-frequency and torque near to designed values.

• Proceedings of the KIEE Conference
• /
• 2005.07b
• /
• pp.1141-1143
• /
• 2005

This paper presents the reasonable design parameters of a SRM for hybrid electric vehicle driving. For the design of SRM, the initial model is designed using the equivalent magnetic circuit method. In order to optimize the SRM for HEV. The initial model is redesigned by FEM with the variation of the stock length and turns of winding. This paper shows that a flat-topped current of a phase can be made from a change of the stack length and the number of turns for high efficiency, high average torque and a lower torque ripple. The change of current falling time as a variation of turn-off angle was shown by FEA. The iron loss and copper loss were described. The torque of the redesigned motor is suitable for low and high speed ranges to drive a HEV that was verified by the speed-torque curve.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2006.08a
• /
• pp.67-69
• /
• 2006

Capacitance and loss values of pentacene MIS capacitors with different thicknesses are measured as a function of frequency for the modeling of the devices. The equivalent circuit for the ideal MIS capacitor is adopted to model the obtained admittance, so the values of $C_i,\;C_d,\;C_b$, and $R_b$ are determined for each pentacene thickness. In the loss curve, broader loss peaks are observed in measurement than the modeling results regardless of the pentacene thickness. By considering the effects of dispersive charge transport in bulk semiconductor, more accurate modeling results are obtained.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.17 no.11 s.114
• /
• pp.1089-1095
• /
• 2006

In this paper, the circuit analysis of three-dimensional bandpass filter with transmission zero in multi-layer printed circuit board is presented. The equivalent circuit of bandpass filter is evaluated by microwave network analysis. Compare to the established paper that have configured the circuit model of filter except the effect of distribute element, the proposed model can include the effect. As a result, the multi-layer PCB bandpass filter with transmission zero has designed by extracting mutual capacitance from electrical component inside inductor. The structure size is only $10mm{\times}20mm{\times}1.251mm$. Measured data of the bandpass filter indicate 1.9 dB of insertion loss and 28 dB of return loss at the center frequency of 1.84 GHz, as well as 43 dB attenuation at the refraction frequency of 2.78 GHz.

• Journal of the Korean Magnetics Society
• /
• v.19 no.1
• /
• pp.5-11
• /
• 2009

The Explosive Magnetic Generator of Frequency (EMGF) has been studied as a method to generate a strong microwave effectively through converting the explosion powder energy into the electromagnetic energy. However, the generated high frequency electromagnetic wave has not been explained clearly yet, for it is known to be difficult to analyze the high frequency electromagnetic wave oscillation using a simple time-varying equivalent circuit model. In this paper, we analyze the problems of the widely used inductance model with an exponential decreasing pattern and investigate the tendency of a more accurate inductance variation model using the finite element method of EMGF inductance by considering the magnetic compression effect. And we have shown via an EMGF output simulation that the new inductance variation model proposed here has an negative effect on EMGF output.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.24 no.3
• /
• pp.245-250
• /
• 2014

Addiction can be largely divided into two categories. One is called medium addiction in which medium itself causes an addiction. Another is called cause addiction that brings addiction through combination of sensitive self and latent personal action. The medium addiction involves addiction phenomena directly caused by illegal drugs, alcohol and various other chemicals. The cause addiction is dependent on personal sensitivities as a sensitive problem of personal and includes cyber addictions such as shopping, work, game, internet, TV, and gambling. In this paper we propose two-dimensional addiction model that are equivalent to using an R-L-C series circuit of Electrical circuit and a Spring-Damper-mass of mechanical system. We also organize a Duffing equation that is added a nonlinear term in the proposed two-dimensional addiction model. We represent periodic motion and chaotic motion as time series and phase portrait according to parameter's variation. We confirm that among parameters chaotic motion had addicted state and periodic motion caused by change in control coefficient had pre-addiction state.

• Journal of Electrical Engineering and Technology
• /
• v.4 no.3
• /
• pp.382-388
• /
• 2009

Recently, hydrogen energy has been anticipated to change the paradigm of conventional power systems because it can expand sustainable energy utilization and conceptually provide remarkable flexibility to power system operation. Since hydrogen energy can be converted to electric energy through fuel cells, fuel cells are expected to play an important role in the future hydrogen economy. In this paper, a Proton Exchange Membrane Fuel Cell (PEMFC) is modeled as an equivalent circuit and its steady-state characteristics investigated using the model. PEMFCs can be connected to power systems through power conditioning systems, which consist of power electronic circuits, and which are operated as distributed generators. This paper analyzes the effects of the characteristics of the PEMFC internal voltages and investigated the dynamic responses of the PEMFC under fault conditions. The results show that the fault current contribution of the PEMFC is different from those of conventional generators and is closely related to its operating point.

• Journal of Power Electronics
• /
• v.17 no.5
• /
• pp.1298-1307
• /
• 2017

The constant on-time current-mode controlled (COT-CMC) switching dc-dc converter is stable, with no subharmonic oscillation in its current loop when a voltage ripple in its outer voltage loop is ignored. However, when its output capacitance is small or its feedback gain is high, subharmonic oscillation may occur in a COT-CMC buck converter with a proportional-integral (PI) compensator. To investigate the subharmonic instability of COT-CMC buck converters with a PI compensator, an accurate reduced-order asynchronous-switching map model of a COT-CMC buck converter with a PI compensator is established. Based on this, the instability behaviors caused by output capacitance and feedback gain are investigated. Furthermore, an approximate instability condition is obtained and design-oriented stability boundaries in different circuit parameter spaces are yielded. The analysis results show that the instability of COT-CMC buck converters with a PI compensator is mainly affected by the output capacitance, output capacitor equivalent series resistance (ESR), feedback gain, current-sensing gain and constant on-time. The study results of this paper are helpful for the circuit parameter design of COT-CMC switching dc-dc converters. Experimental results are provided to verify the analysis results.

• KIPS Transactions on Computer and Communication Systems
• /
• v.3 no.11
• /
• pp.419-426
• /
• 2014

The recent trend of performance increase in the smart mobile devices demands more power consumption and lower batter life time. Among three battery models of mathematical model, electrochemical model and electric model, the Thevenin's equivalent circuit with non-linear function model of SOC in the electrical model is widely used. However, the OCV results have only limited accuracy because of the characteristic shift caused by temperature and age and atypical impedance property that cannot expressed by electrical components. In this paper, the new battery model that improves the accuracy of the existing models is proposed. In the proposed simulator the mathematical model for SOC characteristic is improved and the adjustment for the temperature, the age of battery and atypical electrical characteristics. In the experimental results of predicting of the battery in the static and dynamic state, the proposed simulator shows improved MSE comparing to the results of the existing methods.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.27 no.7
• /
• pp.37-44
• /
• 2013

Phase to ground faults are possibly one of the maximum number of faults in power distribution system. During a ground fault the maximum fault current and neutral to ground voltage will appear at the pole nearest to the fault. Distribution lines are consisted of three phase conductors, an overhead ground wire and a multigrounded neutral line. In this paper phase to neutral faults were staged at the specified concrete pole along the distribution line and measured the ground fault current distribution in the ground fault current, three poles nearest to the fault point, overhead ground wire and neutral line. A simplified equivalent circuit model for the distribution system under case study calculated by using MATLAB gives results very close to the ground fault current distribution yielded by field tests.