• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.280-282
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• 2011

This paper presents a development of voltage compensation dc/dc converter to decrease fuel consumption of RTGC system. We used 3-phase interleaved converter, which has the same structure as the commercially available three-phase inverter, is used. RTGC system is supplied the power from diesel-engine generator. According to power demand, engine speed is varying 20~60Hz, and voltage is varying 210Vac ~ 480Vac. When idle mode or low power operation dc/dc converter operates by constant output voltage control. The perpormance of converter is evaluated through several experiments with a real RTGC. Proposed system can cut down fuel consumption by 36% at idle mode operation.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.255-258
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• 2007

In this paper, a PV multi-string PCS with a grid-connection is proposed. An improved MPPT algorithm for the PV multi-string PCS is suggested. Each PV string has its own MPP tracker and the proposed MPPT algorithm prevents LMPP tracking due to power ripple. In the PV PCS with single-phase inverter has a large current ripple at twice the grid frequency. The current ripple reduction algorithm without external component is suggested. Also, this paper proposes a simple control method to achieve sharing of the PV string voltage and current among the interleaved parallel boost converters. All algorithms and controllers are implemented on a single-chip microcontroller. Experimental results obtained on a 3kW prototype show high performance of the proposed PV multi-string PCS.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.8
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• pp.2077-2089
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• 1996

In this paper, a memory organization and its control method are proposed for the implementation of parallel Virterbi decoders. The design is mainly focused on lowering the hardware complexity of a parallel Viterbi decoder which is to reduce the decoding speed. The memories requeired in a Viterbi decoder are the SMM(State Metric Memory) and the TBM(Traceback Memory);the SMM for storing the path metrics of states and the TBM for storing the survial path information. A general parallel Viterbi decoder for high datarate usually consists of multiple ACS (Add-Compare-Select) units and their corresponding memeory modules.for parallel ACS units, SMMs and TBMs are partitioned into smaller independent pairs of memory modules which are separately interleaved to provide the maximum processing speed. In this design SMMs are controlled with addrss generators which can simultaneously compute addresses of the new path metrics. A bit shuffle technique is employed to provide a parallel access to the TBMs to store the survivor path informations from multiple ACS modules.

• Journal of the Korean Operations Research and Management Science Society
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• v.23 no.3
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• pp.91-108
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• 1998

Automated Storage and Retrieval Systems (AS/RSs) are an important facility for modern material management. The expected benefits of these capital-intensive facilities are gained when their control policies and their physical design parameters are determined simultaneously. In this paper we present several analytical models that capture the impact of the storage assignment policy and of the rack design on the expected storage and retrieval times. Sequential and interleaved service modes are considered for sequencing the storage and retrieval requests. We further investigate the impact of the rack structure on the relative performance of the following storage assignment policies : closest open location (random), full turnover-based policy, and class-based. Our analysis clearly indicates that significant savings in crane travel time are realized when implementing full turnover-based policy, rather than random. These savings become more and more pronounced as the profile of the storage racks approaches the square-in-time shape. Furthermore, it is shown that a class-based policy, with a small number of storage classes, will capture most of these savings and be easier to manage in practice.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.279-280
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• 2013

본 논문에서는 3상 양방향 절연형 인터리브드 DC-DC 컨버터의 병렬 제어기법에 대해 기술한다. 대전력 적용 시, DC-DC 컨버터를 단독으로 운전하는 것이 아닌 병렬로 연결하여 운전을 하게 되는데 이때 발생하는 전류의 불평형을 해결하기 위하여 부스트 모드와 벅 모드에서 저전압측의 전압을 제어하는 전압제어기에 각 컨버터의 전류차를 보상하는 전류제어기를 제안하였며 각 모드에서 전류의 불평형이 보상되는 것을 실험을 통해 검증하였다.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.24-25
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• 2013

본 논문은 단일 전류 센서를 이용한 배터리 충방전용 양방향 3상 인터리브드 컨버터의 전류 제어 방법을 제안한다. 기존의 3상 인터리브드 컨버터 전류 제어는 각 상의 인덕터 전류를 센싱해야만 하는 방식이다. 본 논문에서 제안한 전류 제어 방법은 각 상의 인덕터 전류 센싱없이 단일 전류 센싱만으로 인덕터 전류를 제어 할 수 있다. 시뮬레이션을 통하여 본 논문이 제안한 제어 방법의 타당성과 실효성을 증명한다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.5
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• pp.57-64
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• 2015

This paper proposes a new switching algorithm for an controllable clamp snubber to improve the efficiency of a fly-back converter system. This system uses an controllable clamp method for the snubber circuit for the efficiency and reliability of the system. However, the active clamp snubber circuit has the disadvantage that system efficiency is decreased by switch operating time because of heat loss in resonance between the snubber capacitor and leakage inductance. To address this, this paper proposes a new switching algorithm. The proposed algorithm is a technique to reduce power consumption by reducing the resonance of the snubber switch operation time. Also, the snubber switch is operated at zero voltage switching by turning on the snubber switch before main switch turn-off. Experimental results are presented to show the validity of the proposed controllable clamp control algorithm.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.63-64
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• 2012

본 논문에서는, 태양광 AC 모듈 기반의 인터리브드 플라이백 인버터에서의 동기 정류기를 이용한 소프트 스위칭 제어 기법을 제안한다. 제안된 방식은, 동기정류기를 이용하여 다이오드의 전도손실을 줄이고, 1차측 주스위치의 ZVS(Zero Voltage Switching) 턴-온을 수행하여 스위칭 손실을 저감하였다. 본 논문에서는 제안된 시스템의 타당성을 이론적 분석과 시뮬레이션을 통해 검증한다.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.101-102
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• 2015

This paper is about the suggestion for the development in the commercialization for 3.6kW Class On-Board charger. It is suggesting non-insulation AC-DC Boost Power Factor correction circuit and insulation DC-DC resonant Converter for circuit design. In addition, Input AC voltage in the power supply is DCM control which can be designed to decrease the inductance for the inductor size to be reduced. DCM controls and Interleaved PFC can be designed to decrease the inductor size increasing the power conversions. Also, using the insulation DC-DC resonant converter, the efficiency can be increased. This system is verified using prototype hardware.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.337-338
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• 2012

본 논문에서는 전 영역 ZVS가 가능한 양방향 3상 절연형 인터리브드 DC-DC 컨버터의 제어방법에 대해 서술한다. 3상 절연형 인터리브드 DC-DC 컨버터는 모든 스위치가 ZVS동작을 하여 높은 효율을 갖고 3상 구조를 채택하여 전류경로의 분산을 통한 전력전달 능력의 증대 효과 및 입력전류 리플 크기를 줄여주는 인터리브드 효과를 갖는다. 승압/강압 능력이 있는 부스트/벅 컨버터의 구조는 낮은 권선비의 변압기로 높은 승압/강압 전력변환, 에너지원과 부하 사이에 절연이 가능한 구조이며, 인터리브 동작이 이루어짐에도 불구하고 3상을 각각 제어하지 않고 배터리의 전압전류와 출력전압만을 입력받아 벅모드와 부스트 모드 모두 전압, 전류제어를 수행함으로서 시스템의 간략화가 가능하였다. 따라서 본 논문에서는 제안된 DC-DC컨버터의 제어기를 구성하고 실험을 통해 확인하였다.