• 한국음향학회지
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• 제16권3호
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• pp.106-113
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• 1997

본 논문에서는 저전압 아날로그-디지털 혼성모드 신호처리를 위한 3V CMOS 연속시간 완전균형 적분기가 설계되었다. 설계된 완전균형 적분기의 기본구조는 NMOS와 PMOS 트랜지스터를 이용한 상보형 회로이며, 이러한 상보형 회로는 적분기의 트랜스컨덕턴스를 증가시킬수 있는 장점이 있다. 그리고 트랜스컨덕턴스의 증가는 적분기의 단위이득 주파수, 폴 그리고 영점을 증가시킨다. 소신호해석과 SPICE 시뮬레이션을 통해 기존의 적분기들과 비교하여 이러한 개선점들을 증명하였다. 0.8 3V CMOS CMOS 공정 파라미터를 이용하여 완전균형 상보형 적분기의 응용회로로서 3차 능동 지역통과 필터를 설계하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
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• pp.115-116
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• 2006

Since the discovery of the high-temperature superconductors, many researches have been performed for the practical applications of superconductivity technologies in various fields. As results, significant progress has been achieved. Especially, Superconducting Fault Current Limiter (SFCL) offers an attractive means to limit fault current in power systems. The SFCLS, in contrast to current limiting reactors or high impedance transformers, are capable of limiting short circuit currents without adding considerable voltage drop and energy loss to power systems during normal operation. Under fault conditions, a resistance is automatically inserted into the power grid to limit the peak short-circuit current by transition from the superconducting state to the normal state, the quench. The advantages, like fail safe operation and quick recovery, make SFCL very attractive, especially for rapidly growing power systems with higher short-circuit capacities. In order to verify the effectiveness of the SFCL, in this paper, the analysis of fault current and voltage stability assessment in a sample distribution system and a transmission system are performed by the PSCAD/EMTDC based simulation method. Through the simulation, the advantage of SFCL application is shown, and the effective parameters of the SFCL are also recommended for both distribution and transmission systems. A resistive type component of SFCL is adopted in the analysis. The simulation results demonstrate not only the effectiveness of the proposed simulation scheme but also SFCL parameter assessment technique.

• Journal of Chest Surgery
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• 제23권6호
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• pp.1152-1157
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• 1990

Colloid solution is commonly used to increase the oncotic pressures of priming solutions used in the cardiopulmonary bypass circuit. To study the effectiveness of this practice, we retrospectively evaluated 24 patients undergoing cardiac operations to receive isoelectric solution plus 50 gm of albumin[group A], isoelectric solution plus 25 gm of albumin[group B] and isoelectric solution without albumin[group C] as the prime solution for the bypass circuit. Various clinical parameters related to the perioperative fluid balance, cardiopulmonary function, and renal function were studied. There were no differences between the three groups with regard to postoperative clinical parameter of cardiopulmonary, liver function and renal function. But at the previous report by Cho et al. [38], there was a significant difference between groups with regard to hematologic property, especially in crenated red blood cells. These hematologic events did not affect the clinical outcome but thorough evaluations are needed in order to prove the clinical effect of crenated red blood cell. We conclude that there is no clinically detectable advantage for the routinely supplementing of albumin to the priming solution of bypass circuit in cardiac operations. Whether this practice can be of value in selected cases needs to be further studied.

• 한국전기전자재료학회논문지
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• 제21권8호
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• pp.719-726
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• 2008

In this paper, we designed driving IC for 500 V resonant half-bridge type power converter, In this single-ended level shifter, chip area and power dissipation was decreased by 50% and 23.5% each compared to the conventional dual-ended level shifter. Also, this newly designed circuit solved the biggest problem of conventional flip-flop type level shifter in which the power MOSFET were turned on simultaneously due to the large dv/dt noise. The proposed high side level shifter included switching noise protection circuit and schmmit trigger to minimize the effect of displacement current flowing through LDMOS of level shifter when power MOSFET is operating. The designing process was proved reasonable by conducting Spectre and PSpice simulation on this circuit using 1${\mu}m$ BCD process parameter.

• Journal of Magnetics
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• 제17권1호
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• pp.19-26
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• 2012

This paper deals with the performance analysis and estimation of the electrical parameters of a permanent magnet synchronous generator (PMSG) for hydrokinetic energy conversion applications using vortex induced vibration (VIV). The analytical solutions for the magnetic fields produced by permanent magnets (PMs) and stator winding currents are obtained using a 2D polar coordinate system and a magnetic vector potential. An analytical expression for the 2D permeance is also derived, which takes into account stator skew effects. Based on these magnetic field solutions and the 2D permeance function, electrical circuit parameters such as the backemf constant and the air-gap inductance are obtained analytically. The performances of the PMSG are investigated using the estimated electrical circuit parameters and an equivalent circuit (EC). All analytical results are validated extensively using 2D finite element (FE) analyses. Experimental measurements for parameters such as the back-emf and inductance are also presented to confirm the analyses.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2000년도 학술대회논문집
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• pp.225-230
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• 2000

This paper describes a double-ended current fed push-pull type high frequency resonant inverter used as the power supply for wax-sealing. The proposed inverter can realize ZVS operation by using resonant capacitor to ZVS capacitor and has some merits not only reduction of switch current distribution but also extension of load range compare to the conventional single-ended current fed push-pull type high frequency resonant inverter. This analysis of proposed circuit uses normalized parameter ad characteristic estimation which is needed in each step before design is generally described according to normalized frequency($\mu$), normalized resistance(λ) and parameters. It is also presented as an example of method of the circuit design based on estimation analysis values from theoretical analysis. The theoretical analysis is proved through experiment and this circuit shows that it can be used practically as the power supply system for wax-sealing and DC-DC converter.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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• pp.227-232
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• 2003

Usually, the thrust of a Linear Pulse Motor(LPM) is calculated by magnetic equivalent circuit modelling method. Analytical thrust deviation exists to calculating magnetic flux density by using Permeance Modelling Method, Finite Element Method, and Velocity Electric Motive Force Method. For calculating accuracy thrust by using these every method, the thrust is calculated and compared by Lorentz Force Method, Magnetic Coenergy Method, and Maxwell correspondence force Method. And that becomes important factor at the comparison of each capacity and parameter of motor. So this study wants to compare and analyze measurement data and calculating data of the static thrust of LPM. and then we can get more accuracy method, calculating the static thrust of LPM.

• Journal of Power Electronics
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• 제17권5호
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• pp.1268-1277
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• 2017

Three-phase pulse width modulation (PWM) rectifiers are usually designed under the assumption of ideal ac power supply and input inductance. However, non-ideal circuit parameters may lead to a voltage collapse of PWM rectifiers. This paper investigates the mechanism of voltage collapse in three-phase PWM rectifiers. An analytical stability boundary expression is derived by analyzing the equilibrium point of the averaging state space model, which can not only accurately locate the voltage collapse boundary in the circuit parameter domain, but also reveal the essential characteristic of the voltage collapse. Results are obtained and compared with those of the trial-error method and the Jacobian method. Based on the analysis results, the system parameters can be divided into two categories. One of these categories affects the critical point, and other affects only the instability process. Furthermore, an effective control strategy is proposed to prevent a vulnerable system from being driven into the instability region. The analysis results are verified by the experiments.

• 드라이브 ㆍ 컨트롤
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• 제9권4호
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• pp.58-61
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• 2012

The customers who used the hydroulic system desire the product that has more detailed specification quickly during the industrial technology is developed. Every researcher try to reduce the developed period and to satisfy the customers' desire. Lot's of simulation software and hardware already was used to be satisfied those purpose. But these kind of equipment need a lot of cost to set up and technical knowledge to drive that system. This paper concerns about analog PID controller that can be assembled with a few resistor, condenser and optional amplifier and doesn't need technical knowledge to drive. At the first, the plant was modeled mathematically to design the analog PID controller's circuit. After that, PID controller's parameter was selected by customers' desire. Finally, the analog PID controller's circuit was assembled from the control law. The circuit's availability was confirmed by step response test in the controlled system.

• 조명전기설비학회논문지
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• 제27권5호
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• pp.74-80
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• 2013

This paper presents the transient behavior of the switching surge voltages generated by interruption of DC ground fault currents flowing through metal flexible conduits. All fault circuits consist of line parameters such as resistance, inductance, capacitance and conductance. The use of nonmagnetic metal conduits should be taken into account in order to reduce the inductance of battery charger distribution circuits. The frequency-dependent circuit parameters of metal flexible conduits were measured. The switching surge voltages generated at the ground fault circuit consisted of steel-galvanized alloy and aluminium conduits were investigated. As a result, the impedances of metal flexible conduits are significantly increased over the range of the frequency above 10 kHz and the switching surge voltages generated along aluminium flexible conduit are lower than those along steel-galvanized alloy conduit when DC fault current is interrupted.