• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.22 no.8
• /
• pp.31-37
• /
• 2008

As transmission line is installed by manual operation, it is necessary to scheme the automatic system for stringing transmission wire. For this necessity, the objective of this paper is developed automatic control system for a stringing of transmission wire. In this paper, transmission wire with suspended pattern and ac servo motor for torque generating are modeled. On the basis of wire model, algorithms to determine the reference tension is presented, so as the dip of transmission wire is keep constancy. The control scheme is proposed by the ac servo motor for torque generation and a load cell for a detected tension of transmission wire and implemented. We experimentally show that the performance of the tension response is satisfactory. And also proposed scheme verified the utilities for tension control of transmission wire.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.14 no.3
• /
• pp.88-96
• /
• 2000

The instantaneous power theory have been considered as efficient theory in recent years, because it is easier to understand numerical representation and more soft to control PWM power converter on $\alpha$-$\beta$ stationary reference frame. From the forgoing theory, with regard to the calculating process of compensating reference current, there are many induced components of current/ power, and these components have consequently influence on physical interpretation of instantaneous power theory. Especially, beginners for studing the instantaneous power theory don't have enough informations for standard waveform of induced $\alpha$-$\beta$ components. Therefore, this paper describes simulation works using MATLAB/SIMULINK for $\alpha$-$\beta$ space trajectories and waveforms of $\alpha$-$\beta$ current and power components, induced from the instantaneous power theory. It is respected that the results in this paper are serviceable as basic information to assist beginner for studing the instantaneous power theory.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.26 no.4
• /
• pp.57-66
• /
• 2012

When typical Z-source DC/AC inverter(ZSI) is operated in high voltage gain area, because of its high duty ratio, voltage and current stress in Z-network of typical ZSI are increased. This paper proposes a new switched trans ZSI(STZSI) with two switched trans cells which consist of one trans and two diodes. To confirm the operation performance of the proposed system, the PSIM simulation is performed for typical ZSI, switched inductor ZSI and the proposed STZSI. Voltage / current stress and transient state characteristics of each method are compared under the condition of DC input voltage 100[V] and output phase voltage 66[Vrms]. As a result, we confirmed that transient state of the proposed STZSI is short compared with the conventional ZSI because the high voltage gain is obtained using the same duty ratio, also a low duty ratio is required for the same output voltage. Finally, we could know the proposed system have low voltage and current stress in Z-network compared with the conventional ZSI.

• Journal of the Korean Society for Railway
• /
• v.12 no.2
• /
• pp.254-259
• /
• 2009

DC transit system has been adopted in the metropolitan area, Korea since 1974. Electric multiple (EMU) in this system always reiterates that acceleration and retardation. When EMU decelerates using electric breaking, regenerative power occurs. Regenerative power can be consumed in vicinity EMU on the same line or in resistor. If DC transit system has inverter for reusing regenerative power, Energy efficiency in DC transit system and the replacement cycle of brake shoe in EMU will be increased and dust due to mechanical braking decreased. This paper present the developed inverter for regenerative power and its test equipment. Test for developed inverter is performed at test equipment and is divided into three items, which are regeneration mode, active filter mode, and system link test.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.17 no.2
• /
• pp.279-290
• /
• 2022

A superconducting fault current limiter(SFCL) is a power device that exploits superconducting transition to control currents and enhances the flexibility, stability and reliability of the power system within a few milliseconds. With a high phase transition speed, high critical current densities and little AC loss, high-temperature superconducting (HTS) wires are suitable for a resistive-type SFCL. However, HTS wires due to the lack of optimization research are rather inefficient to directly apply to a fault current limiter in terms of the design and capacity, for the existing method relied the characteristics. Therefore, in order to develop a suitable wire for an SFCL, it is necessary to enhance critical current uniformity, select optimal stabilizer materials and conducted research on the development of uniform stabilizer layering technology. The high temperature superconducting wires manufactured by this study get an average critical current of 804 A/12mm-width at the length of 710m; therefore, conducted research was able to secure economic performance by improving efficiency, reducing costs, and reducing size.

• Journal of Advanced Navigation Technology
• /
• v.26 no.2
• /
• pp.99-104
• /
• 2022

Recently, the domestic demand for weapon systems based on aircraft platforms is gradually increasing. In particular, the demand for effective precision guided missile(PGM) which cruises for several hundred kilometers after launch to strike the ground target is rising drastically, but it is in the early stages of development, and research based on it are limited. This paper is a study on the power converter unit(PCU) within PGM which is mounted on an aircraft platform based on MIL-STD-1760, which is an interface between an aircraft and PGM. We investigated the electrical properties and structure of the umbilical connector, and the aircraft/store electrical interconnection system. Also, the focus on the design specifications of the PCU that supplies power were described. This result 3 phase AC input, which is the state for the guided simulation power supply in the state of being mounted on an aircraft that rectification method with power factor correction(PFC) compared to bridge rectifier circuit. In the future, it may be used as a basis for power supply design on aircraft mounted weapon systems.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.23 no.1
• /
• pp.59-68
• /
• 2009

Fuel cell generators as the distributed generation system with a few hundred watt$\sim$a few hundred kilowatt capacity, can supply the high quality electric power to user as compared with conventional large scale power plants. In this paper, PEMFC(polymer electrolyte membrane fuel cell) generator as micro-source is modelled by using PSIM simulation software and DSP based fuel cell hardware simulator based on the PSIM simulation model is implemented. The relation of fuel cell voltage and current(V-I curve) is linearized by first order function on the ohmic area in voltage-current curve of fuel cell. The implemented system is composed of a PEMFC hardware simulator, an isolated full bridge dc boost converter, and a 60[Hz] voltage source PWM inverter. The voltage-current-power(V-I-P) characteristics of the implemented fuel cell hardware simulator are verified in load variation and transient state and the 60[Hz] output voltage sinusoidal waveform of the PWM inverter is investigated under the resistance load and nonlinear diode load.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.21 no.5
• /
• pp.10-24
• /
• 2007

In the dissertation, a power conversion system for fuel cell is composed of a PWM inverter with LC filter in order to convert fuel cell voltage to a single phase 220[V]. In addition, new insulated DC-DC converters are proposed in order that fuel cell voltage is boosted to 380[V]. In this paper, it requires smaller components than existing converters, which makes easy control. The proposed DC-DC converter controls output power by the adjustment of phase-shift width using switch $S_5\;and\;S_6$ in the secondary switch which provides 93-97[%] efficiency in the wide range of output voltage. Fuel cell simulator is implemented to show similar output characteristics to actual fuel cell. Appropriate dead time td enables soft switching to the range where the peak value of excitation current in a high frequency transformer is in accordance with current in the primary circuit. Moreover, appropriate setting to serial inductance La reduces communication loss arisen at light-load generator and serge voltage arisen at a secondary switch and serial diode. Finally, TMS320C31 board and EPLD using PWM switching technique to act a single phase full-bridge inverter which is planed to make alternating current suitable for household

• Journal of IKEEE
• /
• v.26 no.4
• /
• pp.584-589
• /
• 2022

For DC-AC power conversion from a high-voltage photovoltaic panel to a single-phase grid, the two-stage transformerless inverter with a buck-boost converter followed by a full-bridge inverter is widely used. To avoid an excessive leakage current due to the large parasitic capacitance of the photovoltaic panel, the full-bridge inverter can only adopt the bipolar PWM which results in much higher power loss compared to the unipolar PWM. In order to overcome such a poor efficiency, this paper proposes a new topology in which an IGBT and a diode for circuit isolation are added to the buck-boost converter. The proposed circuit isolation method allows the unipolar PWM in the full-bridge inverter without any increase in the leakage current so that the overall efficiency can be improved. The validity of the proposed solution is verified by computer simulation and power loss calculation.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2005.11a
• /
• pp.305-308
• /
• 2005

풍력 및 태양에너지는 기존의 화력, 수력, 원자력 발전 등을 대신할 친환경적이고 공해가 없으며 양적으로도 무한한 대체 에너지원이다. 계절적인 기상변화 특성을 이용하여 풍력 발전 시스템과 태양광발전 시스템을 상호 보완시킴으로써 안정적인 전력 공급과 에너지이용 효율의 향상을 꾀할 수 있는 풍력-태양광 복합발전 시스템에 대한 관심이 고조되고 있다. 본 연구에서는 이러한 복합 발전 시스템을 효율적이고 안정적으로 운용하기 위하여 시스템의 각종 데이터들을 수집, 분석하고 파일로 저장하며 이를 인터넷을 이용하여 원격에서도 모니터링 할 수 있는 시스템을 구축한다. 여러 가지 교류와 직류의 전압, 전류들을 비롯한 풍속, 조도, 온도 등의 물리량을 측정하기 위하여 여러 형태의 변환기를 사용하였고 신호 조절 회로를 구성하였다. 데이터 수집 보드(DAQ)를 이용하여 컴퓨터로 데이터들을 읽어 들였으며, 시스템 운용을 위한 서버 프로그램과 이를 원격지에서 실시간 모니터링 및 저장된 데이터들을 다운로드 할 수 있는 클라이언트 프로그램을 작성하였다. 측정된 데이터를 시간, 기상 등의 여러 조건과 연관하여 분석하였다.