• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제50권9호
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• pp.459-466
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• 2001

This paper proposes a snubber circuit for flying capacitor multilevel inverter and converter. The proposed snubber circuit makes use of Undeland snubber as basic snubber unit. It has such an advantage of Undeland snubber used in the two-level inverter. Compared with conventional RCD/RLD snubber for multileve1 inverter and converter, the proposed snubber keeps such good features as fewer number of components, reduction of voltage stress of main switching devices due to low overvoltage, and improved efficiency of system due to low loss snubber. In this paper, the proposed snubber is applied to three-level flying capacitor inverter and this feature is demonstrated by computer simulation and experimental result.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2003년도 학술대회 논문집
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• pp.140-142
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• 2003

We have designed a SFQ (Single Flux Quantum) D2 Cell and Inverter(NOT) for a superconducting ALU (Arithmetic Logic Unit). To optimize the circuit, we have used Julia, XIC and Lmeter for simulations and layouts. We obtained the circuit margin of larger than $\pm$25%. After layout, we drew chip for fabrication of SFQ D2 Cell and Inverter. We connected D2 Cell and Inverter to jtl, DC/SFQ, SFQ/DC and RS flip-flop for measurement.

• 전자공학회논문지A
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• 제31A권12호
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• pp.64-70
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• 1994

In this paper, we inverstigated how a parricular internal inverter circuit, which is located far from the input protection in CMOS DRAM, can be easily damaged by external ESD stress, while the protection circuit remains intact. It is shown in a mega bit DRAM that the internal circuit can be safe from ESD by simply improving the input protection circuit. An inverter, which consists of a relatively small NMOSFET and a very large PMOSFET, is used to speed up DRAMs, and the small NMOSFET is vulnerable to ESD in case that the discharge current beyond the protection flows through the inverter to Vss or Vcc power lines on chip. This internal circuit damage can not be detected by only measuring input leakage currents, but by comparing the standby and on operating current before and after ESD stressing. It was esperimentally proven that the placement of parasitic bipolar transistor between input pad and power supply is very effective for ESD immunity.

• 한국소프트웨어감정평가학회 논문지
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• 제16권2호
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• pp.109-115
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• 2020

본 논문에서는 어댑터나 배터리에 의해 단일전원을 공급받는 IT기기에서, 저렴한 buck 소자를 이용해 마이너스 전압을 발생할 때 발생하는 문제점을 분석하였다. 원인 분석을 위해 buck 소자의 동작원리와 inverter 회로의 원리를 살펴보고, buck 소자를 이용해 inverter 회로를 구성했을 떄의 회로적 특성을 분석하였다. 분석 결과 buck 소자를 이용한 inverter회로는 초기에 큰 기동전류가 필요함을 확인하였으며, 특히 전원을 공급하는 회로에서 기동전류에 미치지 못하는 전류용량일 경우 래치 업 현상과 유사한 상태에 빠질 수 있음을 확인하였다. 분석결과를 확인하기위해 실험회로를 구성하고 입력전류를 확인한 결과, 공급전류가 충분한 경우 과전류가 흐르면서 기동됨을 확인하고, 공급전류가 충분치 않은 경우에는 회로가 기동하지 못해 래치 업 현상이 발생해 회로 전체가 위험상태에 도달함을 확인하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 전력전자학술대회
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• pp.314-315
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• 2011

This paper introduces the design and control method of braking chopper circuit which can supply input power to ventilation inverter of traction control system. The DC input voltage from auxiliary block (static inverter) is normally used as an input of ventilation inverter. It converts DC input to AC output voltage to drive cooling fans for traction control system and traction motors. The electrical braking force is very important for high speed train to guarantee safety even though the train is running in the dead section where the pantograph voltage is not supplied. When the high speed train decelerate speed in dead section, the regenerative energy is dissipated by braking resistor. This paper proposed the braking chopper control method to implement rheostatic braking function and the appropriate chopper circuit for supplying voltage source to ventilation inverter during rheostatic braking mode. The proposed chopper circuit makes it possible for traction control system to regenerate power continuously regardless of the existence of pantograph voltage. The feasibility of proposed braking chopper control and circuit were proven by inertia load test and actual train field test.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제50권11호
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• pp.568-574
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• 2001

This paper describes a current fed high frequency resonant inverter can be used as the power supply for wax-sealing. This circuit configuration is composed of conventional two unit inverter of single ended current find type in parallel. The proposed inverter can realize ZVS operation by using resonant capacitor to ZVS capacitor and has merits not only reduction of switch current distribution but also extension of load range in comparison with the conventional single-ended current fed high frequency resonant inverter. This analysis of proposed circuit uses normalized parameter and characteristic estimation which is needed in each step before design is generally described according to normalized frequency($\mu$), normalized resistance(λ) and parameters. On the basis of characteristic values, a method of the circuit design is presented. Also, the theoretical analysis is proved through experiment and this proposed circuit shows that it can be practically used as the power supply system for wax-sealing and DC-DC converter.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.1119-1122
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• 1992

This paper deals with a novel method of modeling and analyzing multilevel pulse width modulation(PWM) inverter/rectifier, which leads to extraction of equivalent circuit in fundamental frequency domain. By the technique, we can draw out the corresponding linear time invariant circuit even thuogh the actual circuit is switched. A static VAR compensator using five-level inverter is modeled and simulated for the verification of the modeling.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 전력전자학술대회 논문집
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• pp.27-30
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• 1998

In this paper, the inverter air-conditioner with Power Factor Correction(PFC) circuit is Presented for obtaining the good system efficiency and cost merit compared with the conventional inverter air-conditioner. The detailed design procedures for getting the optimal passive components are implemented. Through the simulation and experimental results, it is shown that the system efficiency can be improved. Using the designed components, the prototype system is builted and tested to verify the additional good performances of the proposed circuit.

• 전력전자학회논문지
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• 제12권5호
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• pp.386-393
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• 2007

본 논문에서는 CIM(Current Injection Method)을 이용한 charge-pump방식의 plasma backlight용 고압 inverter회로를 제안한다. 고압 inverter에서 에너지 회수회로의 채용은 새로운 시도로서 에너지회수 이외에도 noise에 의한 시스템의 불안정성과 방전안정화에 기여하고 있다. charge-pump방식으로 스위치류의 내압을 저감하므로 cost면에서 매우 유리한 조건을 확립하였으며 CIM(Current Injection Method)방식의 적용으로 high speed 에너지 회수를 가능하게 하였다. 그리고 제안회로의 동작을 모드별로 해석하였으며, 실제 32" 패널에 적용하여 실험함으로써 제안한 회로의 유용성을 입증하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 C
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• pp.1951-1953
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• 2004

In this study, we propose a small high voltage power supply which use a half-bridge ZCS resonant and Cockroft-Walton on circuit, for ESP (Electrostatic Precipitator). This power supply transfers energy from ZCS resonant inverter to step-up transformer and the transformer secondary is applied to the Cockroft-Walton circuit for generating high voltage as discharging source of electrodes. It is highly efficient because its amount of switching losses are reduced by virtue of the current resonant half-bridge inverter, and also due to the small size, low parasitic capacitance in the transformer stage owing to the low number of winding turns of the step up transformer secondary combined with the Cockroft-Walton circuit. From these results, the best operational condition is obtained at the switching frequency of 9 kHz and the duty ratio of 50 % in this ESP.