• Proceedings of the KWS Conference
• /
• 2006.05a
• /
• pp.181-183
• /
• 2006

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.18 no.5
• /
• pp.96-104
• /
• 2004

This paper proposes a dc power regenerating systems, which can generate the excessive dc power from dc bus line to ac supply in substations for traction system The proposed regeneration inverter system for dc traction can be used as both an inverter and an active power filter(APF). As an regeneration inverter mode, it can recycle regenerative energy caused by decelerating tractions and as an active power filter mode, it can compensate for harmonic distortion produced by the rectifier substation. From the viewpoint of both power capacity and switching losses, the system is designed on the basis of three phase PWM inverters and composed of parallel inverters, output transformers, and an LCL filter.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.4 no.2
• /
• pp.128-137
• /
• 1999

Recently the pelionnance of CO2 arc welding machine has been advanced significantly through the adoption of i invelter circuit topology. which made it possible to improve welding perfonnances such as spatter generation and bead s state. But the conventional inverter arc welding machine generates constant output voltage which cause much spatter g generation dUling short-circuit and arc start time because it is unable to control output current instantaneously. So this p paper representes wavefCnm controlled inverter arc welding machine which control the wavefonn of welding current and t thus to suppress the spatter generation. And the system designed in this paper is the digital controller using single chip m microprocessor of 80C196KC. As a result of perfonnance test for this system, the spatter generation is reduced and s shOlt-circuit time period is stabilized compared to conventional one. And more by using switched mode rectifier for A AC/DC power convelter. unity power factor is maintained and low order halmonic spectrum is supressed.

• Journal of IKEEE
• /
• v.24 no.1
• /
• pp.364-367
• /
• 2020

This paper presents the off-grid PV-ESS system of sequential voltage control method applied to OR logic gate. The conventional off-grid PV-ESS system with the low-voltage series connection has problems due to capacity expansion. To solve these problems, this paper proposes a noble PV-ESS system with high efficiency and low cost by applying sequential voltage control technique of the high-voltage series connection of analog circuit type. The input voltage of DC to AC inverter can be converted from the low-voltage by the combinations of series connection of the conventional cascaded 24V solar cell unit modules to the high-voltage of 384V in battery. The output voltage of the battery was 384V as the each input voltage of three phase DC to AC inverter, and the each output voltage of three phase 10kW DC to AC inverter is designed to be AC380V@60Hz as the line to line rms voltage value. To prove the validity of the theoretical analysis by PSIM simulation, the operating characteristics of sequential voltage control system with OR logic gate were confirmed through experiment results.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.7 no.3
• /
• pp.244-252
• /
• 2002

In this paper, do link ripple currents for three-phase ac/dc/ac PWM converters feeding adjustable speed ac machine drives are analysed in a frequency domain. The expression of the harmonic currents is developed by using switching functions of the converter and exponential courier series expansion. The effect of the displacement angle between the switching Periods of line-side converters and motor-side inverters on the dc link ripple currents is Investigated. Also, the influence of asynchronization of PWM is observed. The result of analysis is compared with frequency spectrum which results from PSIM simulation. The proposed analysis technique is useful to understand the principles of P% and to derive an equivalent model of the dc link capacitors in a high frequency range.

• Proceedings of the KIPE Conference
• /
• 2013.07a
• /
• pp.198-199
• /
• 2013

본 논문은 군용 UPS 시스템에서 Dual Active Bridge(DAB) 컨버터를 이용한 절연형 양방향 배터리 충전기를 제안한다. 일반적인 군용 UPS 시스템은 AC-DC 정류기, DC-AC 인버터, 양방향 DC-DC 컨버터, 배터리 충전기, 배터리로 구성되며, 여러 부하상태들에 대한 지속적인 전력공급을 위하여 안정적인 에너지 저장 시스템이 요구된다. 다양한 양방향 DC-DC 컨버터들 중, DAB 컨버터는 buck, boost 동작이 가능한 고효율 절연형 양방향 컨버터이다. 본 논문에서는 6kW(입력 380Vdc, 출력 32/21Vdc) DAB 컨버터에 대한 토폴로지 분석하고, 파라미터 및 제어 알고리즘 설계를 제안하고 시제품을 통해 이를 검증하였다.

• Proceedings of the KIEE Conference
• /
• 1999.07f
• /
• pp.2484-2486
• /
• 1999

본 논문에서는 PWM 승압형 컨버터/인버터를 사용한 교류전동기 구동시스템에서 커먼 모드 전압의 크기를 dc 버스 전압 1/3이하로 제한시키는 새로운 공간전압벡터 PWM 기법을 제안한다. Dc 버스 전압의 2/3에 해당하는 커먼 모드 전압 펄스가 발생하는 경우에 대하여 고찰하고 각각의 경우에 대한 인버터 스위칭 시점의 이동을 통한 제거 방법을 제안한다. 제안된 방법은 부가의 하드웨어를 요구하지 않고 소프트웨어적으로 손쉽게 구현될 수 있으며, 전력변환기의 제어성능에 영향을 미치지 않는다는 장점을 가진다.

• Proceedings of the KIPE Conference
• /
• 2011.07a
• /
• pp.475-476
• /
• 2011

본 논문에서는 차량의 엔진-발전기를 이용한 교류 전원 시스템에 대한 연구를 수행한다. 엔진-발전기의 출력은 다이오드 정류기를 거쳐 직류로 변환되고, 이를 강압형 DC/DC 컨버터를 통해 안정적인 직류전압으로 제어한다. 다시 DC/AC 인버터를 통해 CVCF의 단상, 혹은 3상의 교류전압을 발생한다. PSIM을 이용한 시뮬레이션을 통해 시스템의 성능을 고찰한다.

• Proceedings of the KIEE Conference
• /
• 2006.07b
• /
• pp.1189-1190
• /
• 2006

본 논문은 연료전지와 플라이윌 저장 시스템용을 결합한 복합전원으로 하는 연료전지 발전 시스템의 전력변환장치 연구에 관한 것이다. 이를 위한 전력변환장치는 연료전지로부터 저전압을 상승시키기 고조파 DC-DC 컨버터 이를 안정된 교류전원으로 변환하기 위한 DC-AC 인버터 및 플라이휠에 에너지 회생과 재생하기 위한 DC-AC 컨버터로 구성된다. 본 연구에서는 기존의 UPS 시스템은 AC 발전기 및 배터리를 백업 전원으로 사용하는데 맡은 유해 물질을 발생시키지만, 이 시스템을 사용하면 환경 오염, 높은 효율 및 대용량에 적합하다. 또한, 시뮬레이션을 통하여 연료전지 발전 시스템에 과부하시 안정하게 출력 성능을 가지도록 Fly-Wheel 시스템을 적용한 모의실험 결과를 제시한다.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.10 no.1
• /
• pp.78-86
• /
• 2005

Recently, a fuel cell with low voltage and high current output characteristics is remarkable for new generation system. It needs both a dc-dc boost converter and dc-ac inverter to be used in fuel cell generation system. Therefore, this paper presents dc-dc active clamp current-fed half-bridge converter with ZVS for fuel cell generation system. The proposed converter has outstanding advantages over the conventional dc-dc converters with respect to high efficiency and high component utilization. The Fuel Cell generation system consist of active clamp current-fed half-bridge converter to boost the Fuel Cell(PEMFC) voltage(28∼43[Vdc]) to 380[Vdc]. A single phase full-bridge inverter is implemented to produce 220[Vac], 60[Hz] AC outputs.