• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• 제9권1호
• /
• pp.23-29
• /
• 1995

There are many articles about the HID lamps about it's characteristics and simulation methods for lamp design or ballast design. For the electronic ballasts of HID lamps, There are some problems caused by acoustic-resonance which destabilizes the arc of HID lamps. So, some studies suggest the methods to avoid it. For example, the methods suggested are high frequence driving over 100[kHz], and mixed frequence driving which alternates high frequence and low frequence, and squarewave driving etc. This study suggests the electronic ballast of HID lamps that solves the problems of acoustic-resonance, and can control the luminance by constant current boostes chopper of which frequence is 30[kHz] and by the squarewave driving of which frequence is 55.5[Hz.] As follows, we have the good electronic ballast for HID lamps which has the characteristics of a light weight, and a function of luminance control and a high quality luminosity and which saves electrical energy.

• Journal of IKEEE
• /
• 제22권3호
• /
• pp.539-547
• /
• 2018

Grid-connected inverter is required to cut off the power supplied to the grid at the islanding condition, immediately. For this reason, an islanding detection is an indispensable function for grid-connected distributed generation system. Slip-Mode frequency Shift (SMS) islanding detection method is very popular method to determine the grid state. SMS method supplies the reactive power to the load according to the grid frequency. In the islanding condition of grid, this injected reactive power pulls out the grid frequency from the allowable range, then the inverter system can detect the islanding condition of the grid. The SMS method can detect the islanding state well and does not generate any harmonics of the grid current. However, the reactive power would be generated and the power quality is reduced even though the grid is not islanding condition, but normal condition. In this paper, a modified SMS method is proposed to remove the reactive power in the normal condition. The performance of the proposed method is evaluated by 600W single phase inverter experimental results.

• The Transactions of the Korean Institute of Power Electronics
• /
• 제3권4호
• /
• pp.307-314
• /
• 1998

A novel high power factor Dual Half Bridge Series Resonant Inverter (DHB-SRI) for an induction heating appliance with multiple loads is proposed to remove the interferential acoustic noise caused by the difference between operating frequencies of adjacent loads. The circuit enables independent full power range control of two induction heating elements by one inverter circuit and has minimum switching losses due to the zero voltage switching characteristic. According to the mode analysis, I will explain the operation of the proposed circuit. To evaluate the required cooling capacity, loss analysis is performed through deriving some loss equations. In order to obtain the power factor correction capability and to lessen the system size, suitable design guides are given. Using the designed values, the proto-type circuit with 2.8kW power consumption for each induction heating element is built and tested to verify the operation of the proposed circuit.

• The Transactions of the Korean Institute of Power Electronics
• /
• 제7권1호
• /
• pp.30-40
• /
• 2002

This paper studies the electronic ballast development for 250w MH lamps. We have improved the input power factor using a PFC IC. To provide the rating voltage required In the lamps, we have used the buck type dc-dc converter By this method, the stress of switching devices in inverter can be reduced. The inverter is the Full-Bridge type. To eliminate the acoustic resonance phenomena of MH lamps, we have added the high frequency sinewave voltage to the low frequency square-wave voltage to the lamp. We hove developed the igniter circuit using the L, C devices. We could control dimming of the lamp by varying the output voltage of the buck converter. The time of illuminating lamps and luminous intensity could be adjusted by season and time band. The buck converter output voltage can be controlled and the no load and over current situation were Protected by the development of the microprocessor Program.

• Journal of Energy Engineering
• /
• 제2권1호
• /
• pp.104-113
• /
• 1993

Due to steady increase of electric power demand and decrease of load factor, the economic and reasonable operation of electric power system is necessary. Because of this reason, dispersed battery energy storage system(BESS) with fast response is receiving attractive attention. With these considerations, 20 kVA BESS is designed and tested to investigate the possibility of BESS application to power system. This paper describes the design specifications of simulator and test results. BESS is composed of batteries, conversion equipments, interconnecting equipments to power system, and control parts of the system. The inverter of BESS can carry out two functions as charger and discharger. Also, it can operate as a VAR compensator by four quadrant operation. Since this system is designed as a simulator of MW system, the conceptual design of MW system is possible by using the test result of test system The study of BESS is preliminary stage for the future MW class BESS.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• 제18권11호
• /
• pp.817-825
• /
• 2017

The AC-common bus microgrid system can overcome several weaknesses of the DC microgrid system by interconnecting the DC/AC inverters used for renewable energy with an AC network. Nevertheless, the unbalanced loads inherent in the electric power systems of island and small communities can deteriorate the performance of the AC microgrid system. This is because of the limited voltage regulation capability and mixed power flow in the voltage source inverter. In order to overcome the unbalanced load condition, this paper proposes a voltage and current control algorithm for the 4-leg inverter based on the single phase d-q control method, as well as the modeling of the voltage controller using Matlab/Simulink S/W. From the S/W simulation and experiment of the 250KW proto-type inverter, it is confirmed that the proposed algorithm is a useful tool for the design and operation of the AC microgrid system.

• KIPE Magazine
• /
• 제9권5호
• /
• pp.40-45
• /
• 2004

현대식 파워 컨버터 설계는 가격대비 효율적인 파워 솔루션을 위해 간단한 인터페이스를 가진 소형 IGBT 모듈을 필요로 한다. 전반적으로 낮은 높이, 양쪽에 별도로 부착된 AC 및 DC 터미널, 상부의 드라이버 액세스 등은 현대식 파워 모듈에 대한 최근의 시장 요구 사항이다. 이러한 요구에 부응하여 탄생한 것이 바로 SEMiX 모듈 플랫폼이다. 나아가, 이 논문에서는 모듈에 대한 새로운 드라이버 솔루션으로 기본 구동 기능과 보호 기능을 겸비한 간단한 애드온(add-On) 게이트 드라이버인 SKYPER를 선보인다. 이 논문에서, 다양한 모듈에 대한 SKYPER의 적합성은 SEMiX 예를 통해 성공적으로 검증되었다. SEMiX와 SKYPER 모두 IPM과 같이 작동했으나 스위치 특성 제어에 있어 더 많은 유연성을 제공하여 모듈식 인버터 솔루션을 위한 편리한 구축 블록임을 입증하였다.

• Proceedings of the KIEE Conference
• /
• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
• /
• pp.1719-1721
• /
• 2005

현재 지구 환경 오염에 관한 관심이 증가하면서, 공해가 없는 자연 에너지원에 대한 연구가 많이 진행되고 있다. 그 중에서도 태양전지 분야중 염료감응형 태양전지(DSC)는 Si계 태양전지와 비교하여 낮은 제조비용등 여러 가지 이유로 최근 많은 연구가 진행되고 있다. 따라서 DSC 발전 시스템의 효율 향상이 요구된다. 본 연구에서는 태양전지 분야 중에서 독립적인 발전설비가 필요한 도서 및 산간 지역에 전력을 안정적으로 공급할 수 있는 소형발전용의 설비로 "전압 및 전류의 피드백을 통한 DSC Cell의 독립전원의 안정화"에 관해 연구하였다. DSC Cell측의 DC입력을 받아 Boost Converter로 승압 후 Full Bridge 인버터를 사용하여 단상 220V 60Hz의 상용전원으로 변환하였다. 여기서는 32Bit 마이크로프로세서인 DSP TMS320F2812의 A/D변환기능을 이용하여 Boost Converter의 스위칭과 Full Bridge 인버터의 스위칭을 제어하였다. 특히 TMS320F2812의 RTC(Real Time Clock)를 이용하여 출력전압의 안정성 향상에 주목적을 두었다. 실험결과 출력단에서는 220V 변동범위 0.2% 주파수 60Hz의 상용전원을 얻었으며, 프로그램의 개선을 통하여 출력전압의 변동범위를 감소시켜야 될 것이다.

• Proceedings of the KIPE Conference
• /
• 전력전자학회 2019년도 전력전자학술대회
• /
• pp.354-355
• /
• 2019

본 논문은 Polymer Dispersed Liquid Crystal(PDLC)의 구형파 구동방식에 따른 전기광학적 특성을 비교한다. 현재 PDLC는 변압기를 사용하여 전압가변이 힘들어 ON/OFF 기능으로만 사용한다. PDLC 구동시스템에 전력변환장치를 적용하면 전압가변이 용이하여 PDLC의 투과도 조절이 가능하다. 구형파 구동방식 중 인버터의 DC Link Voltage를 가변하는 방식과 Duty ratio를 가변하는 두 방식의 전기광학적 특성을 비교하였다. 이를 실험을 통하여 전기광학적 특성을 분석하였다.

• Proceedings of the KIPE Conference
• /
• 전력전자학회 2019년도 전력전자학술대회
• /
• pp.362-363
• /
• 2019

비상발전기를 사용하여 무정전 시스템을 구성할 경우, 발전기 시스템이 정전을 인식하고 비상발전기의 기동하는 시간동안은 정전이 발생함으로 통상적으로 단주기 ESS와 결합한 UPS 시스템을 구축하게 된다. 이 경우 UPS 시스템 구축을 위한 ESS 시스템과 인버터에 대한 부담이 존재한다. 본 논문에서는 비상발전기와 엔진의 동력전달 부 사이에 플라이휠과 전자식 클러치에 의한 새로운 비상발전기 단독형 UPS 시스템을 제안한다.