• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.659-662
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• 1999

As utility pollution take a growing interest, ac/dc converter optimizing utility condition has been vigorously studied in decades. In this paper three phase DCM converter is analyzed and equations for average input currents are presented. Also relationships of voltage gain & duty according to angular velocity are presented and variable frequency controller is implemented using reset integrator which is designed in detail. In result power factor and THD characteristics of 3-stage and 4-stage operation ae compared respectively.

• Toxicological Research
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• v.9 no.2
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• pp.253-262
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• 1993

The effects of dichloromethane (DCM) on carbon tetrachloride (CT) toxicity were examined in adult male rats. A concomitant treatment of rats with DCM (0.3, 0.6, 1.2 g/kg, po) significantly potentiated the hepatotoxicity of CT (1.0 g/kg, po) as determined by increase in serum GPT (glutamic pyruvic transaminase), GOT (glutamic oxaloacetic transaminase), and SDH (sorbitol dehydrogenase) activity 24 hr following the treatments. Serum LDH (lactate dehydrogenase) activity was increased by either DCM or CT treatment.

• Proceedings of the KIPE Conference
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• 2013.11a
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• pp.159-160
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• 2013

본 논문에서는 연료전지를 사용하여 2차 전지를 충전시키는 동기식 부스트 컨버터를 제어하는 방식을 제안한다. 고효율을 위한 동기식 부스트 컨버터는 기존의 부스트 컨버터의 다이오드 대신 MOSFET을 사용한다. 이때 연료전지의 전압이 배터리의 전압보다 낮기 때문에 양방향 소자인 MOSFET의 특성상 DCM구간에서 역전류가 발생한다. 연료전지의 긴 기동시간으로 인해 초기 동작 시 소프트 스타트가 필요한데 이때 역전류가 발생할 수 있는 DCM구간이 나타난다. 시스템 제어를 위해 사용된 mode boundary detector은 CCM과 DCM을 구분해주어 컨버터를 제어한다. CCM구간에서는 동기식으로 부스트 컨버터가 동작되고 DCM구간에서는 기존의 다이오드를 사용하는 방식으로 역전류를 방지한다. 시뮬레이션을 통해 논문의 타당성을 증명하였다.

• Journal of Electrical Engineering and Technology
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• v.10 no.6
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• pp.2307-2314
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• 2015

In this paper, a discontinuous conduction mode (DCM) frequency control algorithm is proposed to reduce the input current ripple of a multi-phase interleaved boost converter. Unlike conventional variable duty and constant frequency control, the proposed algorithm controls the switching frequency to regulate the output voltage. By fixing the duty ratio at 1/N in the N-phase interleaved boost converter, the input current ripple can be minimized by ripple cancellation. Furthermore, the negative effects of the diode reverse recovery current are eliminated because of the DCM characteristic. A frequency controller is designed to employ the proposed algorithm considering the magnetic permeability change. The proposed algorithm is analyzed in the frequency domain and verified by a 600 W three-phase boost converter prototype that achieved 57% ripple current reduction.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.257-267
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• 2006

The earth retaining wall systems for excavation works in a populated urban area or a poor soil deposit can be limited due to various restriction. Thus there are various methods to be applied for them such as the soldier pile method, the diaphragm wall with counterfort and so on. In this study, the self-supported earth retaining wall using the DCM(Deep Cement Mixing) method, including its merits, demerits and some important characteristics occured in the design and the construction stage, was introduced. It might be reference for the other design and construction procedures using the DCM method.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.4
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• pp.369-373
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• 2001

This paper is concerned with a transfer alignment of SDINS under ship motions. To reduce alignment errors induced by the ship body flexure, an error compensation method is suggested based on velocity and DCM partial matching, and by interpreting the simulation results and comparing with the conventional velocity and quaternion partial matching, it is shown that the proposed method is effective enough to improve the azimuth alignment performance.

• Journal of Electrical Engineering and Technology
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• v.5 no.3
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• pp.477-483
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• 2010

This paper is studied on a novel buck-boost isolated converter for high efficiency and high power factor. The switching devices in the proposed converter are operated by soft switching technique using a new quasi-resonant circuit, and are driven with discontinuous conduction mode (DCM) according to pulse width modulation (PWM). The quasi-resonant circuit makes use of a step up-down inductor and a loss-less snubber capacitor. The proposed converter with DCM also simplifies the requirement of control circuit and reduces a number of control components. The input ac current waveform in the proposed converter becomes a quasi sinusoidal waveform in proportion to the magnitude of input ac voltage under constant switching frequency. As a result, it is obtained by the proposed converter that the switching power losses are low, the efficiency of the converter is high, and the input power factor is nearly unity. The validity of analytical results is confirmed by some simulation results on computer and experimental results.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.349-350
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• 2010

본 논문에서는 부스트 컨버터와 플라이백 컨버터가 통합된 단일(Single Stage) 역률 보상 회로의 2차측에 Voltage Doubler를 적용한 새로운 역률 보상회로를 제안한다. 제안하는 회로는 불연속 모드(DCM-DCM)로 동작하며, 스위치 전압 및 전류 스트레스를 저감하고 2차측 다이오드의 전압 스트레스를 저감시키는 특징이 있다. 120 V LED 구동 드라이버 사양의 실험을 통해 제안한 회로의 동작을 검증한다.

• Proceedings of the KIPE Conference
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• 2010.11a
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• pp.363-364
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• 2010

Most LED drivers uses current control method to adjust LED current. Using AC power grid such as off-line converter, Buck topology is popular because input voltage of LED driver is much higher than LED output voltage. Normally DCM current control is more popular than CCM current mode control in the range of below 50W, But DCM characteristics are dependent on the input voltage variation. This paper deals with what should be considered in DCM for LED driver with valley fill circuit.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.6
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• pp.389-396
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• 2018

This study proposes a control method using a repetitive controller for a boost-type PFC rectifier with an APD circuit structure to improve the current distortion caused by DCM condition. Conventional proportional integral controllers have bandwidth limitations in DCM conditions. The performance improvement of the APD controller in the DCM region is verified through simulations and experiments on the compensation of harmonics by the repetitive controller.