• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.971-974
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• 1999

A offset compensated class A bipolar second-generation current conveyor (CCII) for high-accuracy current-mode signal processing was proposed. The CCII adopts two diode-connection transistor between voltage input and voltage output to reduce offset voltage. Experiments show that the proposed CCII has offset voltage of 0.05 ㎷, input impedance of 2 Ω and the 3-㏈ cutoff frequency of 30 MHz when used a voltage amplifier. The power dissipation is 6 ㎷.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.1267-1269
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• 2000

New switching signal pattern for four switches is proposed to prevent the shortage of PWM ac choppers. In the proposed technique, four signals to four power switches are generated without current transformer, while the conventional technique requires sensing the polarity of input voltage by voltage comparator and checking the direction of input current by the current transformer. The signal circuit built by the proposed technique is simple, and reduces also the switching loss.

• 전기학회논문지
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• 제61권10호
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• pp.1432-1441
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• 2012

In this study, an improved LCCT(Inductor-Capacitor-Capacitor-Trans) Z-source inverter(Improved LCCT ZSI) with characteristics of Quasi Z-source inverter(QZSI) and LCCT Z-source inverter(LCCT ZSI) is proposed. The proposed inverter can also reduce the voltage stress and input current/capacitor voltage ripples compared with conventional LCCT ZSI and Quasi ZSI. A two winding trans in Z-impedance network of the conventional LCCT ZSI is replaced by a three winding trans in the proposed inverter. To verify the validity of the proposed inverter, a DSP controlled hardware was made and PSIM simulation was executed for each method. Comparing the current and voltage ripples of each method under the condition of input DC voltage 70[V] and output AC voltage 76[Vrms], the input current and capacitor voltage ripple factors of the proposed inverter were low as 11[%] and 1.4[%] respectively. And, for generation of the same output AC voltage of each method, voltage stress of the proposed inverter was low as 175[V] under the condition of duty ratio D=0.15. As mentioned above, we could know that the proposed inverter have the characteristics of low voltage stress, low ripple factor and low operation duty ratio compared with the conventional methods. Finally, the efficiency according to load change/duty ratio and the transient state characteristics were discussed.

• 수산해양교육연구
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• 제12권2호
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• pp.142-151
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• 2000

The studies on the electronic control fuel injection system for a DI diesel engine have done for reducing the exhaust emission and improving fuel consumption. The electronic control fuel injection system is classified into a common rail system, a unit injector system and a high pressure injection system. The characteristics of these systems are largely depends on the operating characteristics of its solenoid that have high speed on-off operation. In order to improve these characteristics of fuel injection system, it is necessary to design the optimal shape of solenoid and select the input method of its power source. It was proposed HELENOID, COLENOID, DISOLE, and Multipole Solenoid in the studies of design for the optimal shape of solenoid. The studies on the energizing method, input method for power of solenoid were dealt with the conventional energizing method, the chopping method and the pre-energizing method. In order to find out the high response characteristics of solenoid, it is necessary to test the performance of optimally designed solenoid with a new energizing method. In this paper, the solenoid of multi-pole type with plat armature and its power control unit to control input current by the chopping method designed, and its response tests were performed according to its energizing conditions. As a result, the maximum input current for solenoid was controlled by the period of first stage exciting current and chopping duty ratio of control stage exciting current, and the fastest "on" time was able to get 0.46ms. The conditions of fastest "on" time was 0.3ms for first stage exciting current, 0.16ms for control exciting current and 75% for chopping duty ratio.

• 전력전자학회논문지
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• 제11권2호
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• pp.142-148
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• 2006

본 논문에서는 역률개선과 고효율로 동작되는 새로운 승압형 AC-DC 컨버터를 제안한다. 제안된 컨버터는 입력전류 불연속제어로 구동되고, 스위치의 시비율 일정제어에 의해 입력전류는 교류 입력전압의 크기에 비례된 불연속적인 정현파 형태로 주어진다. 그 결과 입력역률은 거의 단위역률로 주어지고, 시비율 일정제어에 의해 제안된 컨버터는 제어기법이 간단하게 된다. 일반적으로 전류불연속 제어에 의한 컨버터의 경우, 사용된 스위치의 턴-온 동작은 영전류 스위칭으로 되는 장점이 있지만, 스위치의 턴-오프 동작은 최대 전류에서 스위칭되어 스위칭 손실을 증대시키고 스위치의 과중한 스트레스를 가져오게 된다. 이것은 컨버터의 효율을 저하시키는 요인이다. 본 논문에서는 부분적인 공진회로 동작에 의한 새로운 소프트 스위칭 회로가 설계되어 사용된 제어스위치들의 턴-온, 턴-오프 동작을 소프트 스위칭으로 만들어 컨버터의 효율을 증대시킨다.

• 대한전자공학회논문지SD
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• 제48권12호
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• pp.82-90
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• 2011

저전력 전류-모드 신호처리를 위해 새로운 AB급 전류 감산기와 이를 이용한 노튼(Norton) 증폭기를 설계하였다. 전류 감산기는 트랜스리니어 셀(translinear cell), 2개의 전류 미러, 그리고 공통-이미터 증폭기로 구성되었다. 전류 감산의 원리는 트랜스리니어 셀로 입력되는 두 전류의 차가 전류 미러에 의해 얻어지고 이 전류는 공통-이미터 증폭기에 의해 ${\beta}$배 증폭되는 것이다. 노튼 증폭기는 설계한 AB급 전류 감산기와 광대역 전압 버퍼(buffer)로 구성되었다. 시뮬레이션 결과 전류 감산기는 $20{\Omega}$의 입력 저항, 50배의 전류 증폭도, $i_{IN1}$ > $i_{IN2}{\geq}4I_B$의 전류 입력 범위를 갖고 있다는 것을 확인하였다. 노튼 증폭기는 ${\pm}2.5V$ 공급전압에서 312MHz의 단위-이득 주파수, 130dB의 트랜스래지스턴스(transresistance), 4mW의 소비전력은 갖고 있다.

• Journal of Power Electronics
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• 제10권1호
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• pp.9-13
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• 2010

This paper proposes an input-series-output-parallel connected ZVS full bridge converter with interleaved control for photovoltaic power conditioning systems (PV PCS). The input-series connection enables a fully modular power-system architecture, where low voltage and standard power modules can be connected in any combination at the input and/or at the output, to realize any given specifications. Further, the input-series connection enables the use of low-voltage MOSFETs that are optimized for a very low RDSON, thus, resulting in lower conduction losses. The system costs decrease due to the reduced current, and the volumes of the output filters due to the interleaving technique. A topology for a photovoltaic (PV) dc/dc converter that can dramatically reduce the power rating and increase the efficiency of a PV system by analyzing the PV module characteristics is proposed. The control scheme, consisting of an output voltage loop, a current loop and input voltage balancing loops, is proposed to achieve input voltage sharing and output current sharing. The total PV system is implemented for a 10-kW PV power conditioning system (PCS). This system has a dc/dc converter with a 3.6-kW power rating. It is only one-third of the total PV PCS power. A 3.6-kW prototype PV dc/dc converter is introduced to experimentally verify the proposed topology. In addition, experimental results show that the proposed topology exhibits good performance.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권4호
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• pp.183-190
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• 2003

We report the performance of an open-frame type low-voltage high-current DC-DC converter module developed using an active clamp forward converter circuit and current doubler rectifier. The converter module is designed with the specifications of an 1.8V output voltage, 25A output current, and 36-75V input voltage. The synchronous rectifier is used to reduce the conduction fuss at high current level and current-mode control is adapted to enhance the flexibility in the system configuration. A prototype converter module is successfully implemented within 10mm height and half brick size (58${\times}$61mm), and recorded an 84% efficiency and 4% voltage regulation for the entire input voltage range, thereby demonstrating its application potentials to future telecommunication electronics.

• 대한전기학회논문지:전력기술부문A
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• 제52권4호
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• pp.183-183
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• 2003

We report the performance of an open-frame type low-voltage high-current DC-DC converter module developed using an active clamp forward converter circuit and current doubler rectifier. The converter module is designed with the specifications of an 1.8V output voltage, 25A output current, and 36-75V input voltage. The synchronous rectifier is used to reduce the conduction fuss at high current level and current-mode control is adapted to enhance the flexibility in the system configuration. A prototype converter module is successfully implemented within 10mm height and half brick size (58×61mm), and recorded an 84% efficiency and 4% voltage regulation for the entire input voltage range, thereby demonstrating its application potentials to future telecommunication electronics.

• 마이크로전자및패키징학회지
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• 제15권3호
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• pp.19-25
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• 2008

본 논문에서는 고역률과 고효율로 동작하는 새로운 스텝-업 AC-DC 초퍼에 대해 제안한다. 제안한 초퍼는 전류 불연속제어로 구동되고, 스위치의 듀티율 일정제어에 의해 입력전류는 교류 입력전압의 크기에 비례된 불연속적인 정현파 형태로 주어진다. 그 결과 입력역률은 거의 단위역률로 되고, 듀티율 일정제어에 의해 제안한 초퍼는 제어기법이 간단하게 된다. 일반적으로 전류불연속 제어에 의한 초퍼의 경우, 사용된 스위치의 턴-온 동작은 영전류 스위칭으로 되는 장점이 있지만, 스위치의 턴-오프 동작은 최대 전류에서 스위칭되어 스위칭 손실을 증대시키고 스위치의 과중한 스트레스를 가져오게 된다. 이것은 AC-DC 초퍼의 효율을 저하시키는 요인이다. 본 논문에서는 부분공진기법에 의한 새로운 소프트 스위칭 회로가 설계되어 사용된 제어스위치들의 턴-온, 턴-오프 동작을 소프트 스위칭으로 만들어 초퍼의 효율을 증대시킨다.