• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.562-564
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• 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.

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

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.2
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• pp.137-144
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• 2011

A Simple equivalent circuit model is developed for a wireless energy transfer system via coupled magnetic resonances and a practical design method is also provided. Node equations for the resonance system are built with the method, expanding on the equations for a transformer, and the optimum distances of coils in the system are derived analytically for optimum coupling coefficients for high transfer efficiency. In order to calculate the frequency characteristics for a lossy system, the equivalent model is established at an electric design automation tool. The model parameters of the actual system are extracted and the modeling results are compared with measurements. Through the developed model, it is seen that the system can transfer power over a mid-range of a few meters and impedance matching is important to achieve high efficiency. This developed model can be used for a design and prediction on the similar systems such as increasing the number of receiving coils and receiving modules, etc.

• KIEE International Transactions on Electrophysics and Applications
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• v.5C no.6
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• pp.233-241
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• 2005

The present model of a SF6 arc accounts for the copper vapour contamination from the electrodes inside a Laval nozzle of a circuit breaker. Steady state simulations have been done for the arc with electrode gap of 60mm and DC electric current of 500A, 1000A and 1500A for both cases with and without copper contamination. The effects of electrode polarity are considered for the arc current of 1000A. It was found out that evaporation of copper from the anode results in a cooling of the arc in a region close to the electrodes. The electrical potential across the electrodes is not sensitive to the presence of copper vapour, typically less than $4\%$ difference. Transient analysis has been done in order to obtain the arc properties at current zero. The arc current is increased linearly from -1000 to 0A when the upstream electrode is cathode with constant dI/dt of $27.0A/{\mu}s$ (or decreased linearly from 1000 to 0A when upstream electrode is anode). It has been predicted that the presence of copper vapour reduces the interruption capability of the breaker.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.371-375
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• 2003

In this paper, a new design method for coupled-line filters with tapped input/output has been developed. The design equations for this tapped filter have been obtained using a new equivalent circuit model of tapped lines. From an edge coupled-line filter, tapped lines replaces the input/output coupled lines which tend to have very narrow gaps (few mils). Therefore, tapped coupled-line filters tend to be less sensitive to filter fabrication tolerances and to be easily fabricated using milling tools. The new filter design algorithm allows very accurate filter design for frequencies less than 20 GHz and bandwidth less than 20%. Above 20 GHz, the filter performance can be optimized starting from the filter design algorithm in this paper. Simulation problems with 2-D EM tools to characterize filter performance at high frequencies have shown to be solved by providing a channel for the filter to eliminate higher order modes.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.3
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• pp.122-129
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• 2001

Exact simulation of conducted EMI in switched mode power supplies is proposed. In order to achieve exact simulation, PSPICE active component ABM model and modified transformer model are proposed. Each model parameter is extracted from measurements and data-books. PSPICE simulation results with high frequency PCB pattern model are accordant with EMI measurements for a 50[W] isolated flyback converter. EMI relations of each component and EMI patterns are analyzed.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.171-171
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• 2010

An innovative design of a floating-buoy wave energy converter (WEC) using hydrostatic transmission (HST), named HSTWEC, is presented in this paper. The system is designed to convert ocean wave fluctuation into electricity by using the HST circuit and an electric generator. Based on the floating-buoy concept, the wave forces the sub-buoy to move up and down. Consequently, the electric power can be obtained from the generator in both the moving directions of the sub-buoy through the HST circuit as shown in Fig. 1. In order to investigate the HSTWEC operations, a mathematical model of the system is indispensible. In addition, the method to control the HSTWEC, including: pump displacement control, tension adjustment control and ballast weight control, is also discussed in this paper. Finally, the design concept as well as simulation results indicated that this HSTWEC design is an effective solution and possible to fabricate for wave energy generation.

• Journal of information and communication convergence engineering
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• v.13 no.3
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• pp.189-196
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• 2015

In this paper, we present a rotating auto-zeroing offset cancellation technique, which can improve the performance of touch screen sensing circuits. Our target touch screen detection method employs multiple continuous sine waves to achieve a high speed for large touch screens. While conventional auto-zeroing schemes cannot handle such continuous signals properly, the proposed scheme does not suffer from switching noise and provides effective offset cancellation for continuous signals. Experimental results show that the proposed technique improves the signal-to-noise ratio by 14 dB compared to a conventional offset cancellation scheme. For the realistic simulation results, we used Cadence SPECTRE with an accurate TSP model and noise source. We also applied an asymmetric device size (10% MOS size mismatch) to the OP Amp design in order to measure the effectiveness of offset cancellation. We implemented the proposed circuit as part of a touch screen controller system-on-chip by using a Magnachip/SK Hynix 0.18-µm complementary metal-oxide semiconductor (CMOS) process.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.161-161
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• 2010

In order to achieve low power consumption and the uniform power spectrum of LED BLU (Back Light Unit) system, new circuits with a 2 stage L-C (Inductor-Capacitor) coupler have been proposed. From the simulation results based on our proposed model, the ripple power of the L-C regulation-embedded BLU circuit shows a dramatic reduction by more than 89.3% as compared to the normal BLU (without L-C circuits). This indicates that the proposed circuit is very promising for the realization of high-efficiency BLU circuits.

• Electrical & Electronic Materials
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• v.9 no.10
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• pp.1019-1026
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• 1996

In this study, we may be presented the carrier oscillation properties for the low-voltage varistor fabricated by a new method of three composition seed grain, in order to analyze the behavior of carriers at the its equivalent circuit model. The oscillation phenomena of carriers appeared from current-voltage characteristics under knee voltage is shown by the transient flow of nontrapped carriers group in the trap level of intergranular layer, surface state and/or depletion layer. In particularly, current oscillation phenomena is hardly shown in the high electric field. It is that the injected carriers from both electrodes are directly from the conduction band of forward biased ZnO grain through the intergranular layer into the reverse biased ZnO grain, because the trap level in the electric field above the knee voltage is mostly filled.