• 반도체디스플레이기술학회지
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• 제17권1호
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• pp.21-26
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• 2018

In this paper, a multiple coupling inductor with expandable-integrated magnetic structure was proposed to enable miniaturization of external switched mode power supply (SMPS) for a large display. Inductance formula of the proposed inductor structure was derived through magnetic circuit analysis for a simple inductance designing process. The proposed inductor was applied into a 1kW class interleaved bridgeless power factor correction circuit which requires four inductors, and experimental steady state result of the circuit was compared. According to the experimental result, it was found that the proposed multiple coupling inductor shows the electrical characteristics that can replace the conventional separated inductors and is suitable for miniaturization of the SMPS since the circuit configuration is possible with one shared inductor.

• 한국시뮬레이션학회논문지
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• 제4권2호
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• pp.41-60
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• 1995

The IGBT(Insulated Gate Bipolar Transistor) is a power semiconductor device that has gained acceptance among circuit design engineers for motor drive and power converter applications. IGBT devices(International Rectifier, Proposed proposed model etc) have the best features of both power MOSFETs and power bipolar transistors, i.e., efficient voltage gate drive requirememts and high current density capability. When designing circuit and systems that utilize IGBTs or other power semiconductor devices, circuit simulations are needed to examine how the devices affect the behavior of the circuit. The interaction of the IGBT with the load circuit can be described using the device model and the state equation of the load circuit. The voltage rise rate at turn-off for inductive loads varies significantly for IGBTs with different base life times, and this rate of rise is important in determing the voltage overshoot for a given series resistor-inductor load circuit. Excessive voltage overshoot is potentially destructive, so a snubber protection circuit may be required. The protection circuit requirements are unique for the IGBT and can be examined using the model. The IGBT model in this paper is verified by comparing the results of the model with experimented results for various circuit operating conditions. The model performs well and describes experimented results accurately for the range of static and dynamic condition in which the device is intended to be operated.

• ETRI Journal
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• 제38권2호
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• pp.272-279
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• 2016

In this paper, a new structure for an advanced high holding voltage silicon controlled rectifier (AHHVSCR) is proposed. The proposed new structure specifically for an AHHVSCR-based electrostatic discharge (ESD) protection circuit can protect integrated circuits from ESD stress. The new structure involves the insertion of a PMOS into an AHHVSCR so as to prevent a state of latch-up from occurring due to a low holding voltage. We use a TACD simulation to conduct a comparative analysis of three types of circuit - (i) an AHHVSCR-based ESD protection circuit having the proposed new structure (that is, a PMOS inserted into the AHHVSCR), (ii) a standard AHHVSCR-based ESD protection circuit, and (iii) a standard HHVSCR-based ESD protection circuit. A circuit having the proposed new structure is fabricated using $0.18{\mu}m$ Bipolar-CMOS-DMOS technology. The fabricated circuit is also evaluated using Transmission-Line Pulse measurements to confirm its electrical characteristics, and human-body model and machine model tests are used to confirm its robustness. The fabricated circuit has a holding voltage of 18.78 V and a second breakdown current of more than 8 A.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1999년도 전력전자학술대회 논문집
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• pp.407-410
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• 1999

Potential-source controlled excitation system had been developed for synchronous generator in In-Chun thermal power plant #4 by KEPRI. This paper describes the characteristics of Main/Standby control system employed analog, digital circuit devices (hybrid type) and 3 PCRs(Phase Controlled Rectifier)

• 전력전자학회논문지
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• 제4권2호
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• pp.128-137
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• 1999

최근 전력전자기술 및 인버터 회로의 다양한 제어기법의 발달에 따라서 용접기 분야에서의 용접성능 향상에 관한 다양한 연구가 진행되고 있으며 특히{{{{ { CO}_{2 } }} 아크 용접기의 경우 용접성능을 좌우하는 스패터 발생을 최소화 하는 기법이 활발하게 연구되고 있다. 그러나 현재까지는 용접기의 출력전압을 정전압으로 제어하는 방식을 사용함에 따라 용접기의 금속이행과정을 임의로 제어하는 것이 불가능하였고, 특히 스패터가 다량으로 발생하는 저전류영역의 금속이행과정인 단락이행에서의 스패터 저감을 기대하기가 어려웠다. 따라서 본 논문에서는 마이크로프로세서를 이용한 인버터 출력전류의 파형제어기법을 사용하여 인버터 아크 용접기의 출력전류를 순시적으로 제어함에 의하여 스패터 저감, 단락주기의 안정화 및 순간단락현상 감소의 측면에서 용접성능을 개선위한 연구를 수행하였고 이상의 연구에 대한 결과를 제시하였고, 또한 인버터 아크 용접기의 AC/DC 전력변환장치로 SMR(Switched Mode Rectifier)를 사용하여 시스템을 단위역율로 운전하였으며 입력전류의 저차 고조파 억제효과를 얻을 수 있었다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2016년도 전력전자학술대회 논문집
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• pp.335-336
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• 2016

This paper introduces a bidirectional full-bridge converter with new active damp structure. The proposed active damp circuit can damp the oscillating voltage across the rectifier diodes with a smaller voltage stress of the damping capacitor and eliminate the circulating current. In addition, the proposed converter can achieve additional advantages such as nearly ZCS switching for leading-leg switches and no recovery current for rectifier-bridge by the suitable design of the damp capacitor to resonate with leakage inductor. Since the ZVS is achieved for both leading-leg and lagging-leg switches by the magnetizing current of the transformer, it can be achieved regardless of the load variation. A 3.3 kW prototype converter is implemented for vehicle-to-grid (V2G) application and the advantages of the proposed converter are verified by the experiments. The maximum efficiencies of 98.2% and 97.6% have been achieved for the buck mode and boost mode operation, respectively.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 하계학술대회 논문집
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• pp.136-138
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• 2008

The output voltage of synchronous generator is regulated constantly by field current control in excitation system. Most of ship generator exciter system uses the thyristor phase controlled rectifier. However this rectifier is difficult to realize that the speed control system because its control period is slower than MOSFET and IGBT type converter. Therefore, this paper deals with PMG(Permanent Magnet Generator) type digital excitation system using MOSFET for ship synchronous generator. The organization of this excitation system is very simple. When the generator is under the short circuit accident, the output voltage becomes zero state and AVR can not operate. Thus generator requires the function for flowing output current through CBS. The performance of the proposed system is evaluated on a 10kVA experimental prototype circuit in place of real ship generator.

• Journal of Advanced Marine Engineering and Technology
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• 제16권4호
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• pp.102-112
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• 1992

The three-phase full(6-pulse) bridge controlled rectifier is one of the most widely used types of solid-state converters in DC drive applications for higher performance. In most of the previous designs, the gate control circuits of the converter have been designed with analog method which can be easily affected by noise. Nowdays with advances of microelectronics and power electronics, microprocessor and pheripal LSIs are increasingly used for eliminating this problems. In this paper, a novel general-purpose microprocessor -based firing system and control scheme for a three-phase controlled rectifier bridge has been developed and tested. Using the phase relations between ${\Delta}$-Y transformer in power operation part, gate pulse of the converter is generated with real time process so that microprocessor may share its time to control algorithms efficiently. The firing angle of the converter is smoothly controlled in the range of 0 $^{\dirc}$ to 180$^{\dirc}$ with a fast respone and a constant open loop gain, even for the case where the converter is fed by a weak AC system of unregulated frequency. The hardware and software control circuit implementation built around a 80286 microprocessor is discussed, and the experimental results are given. This scheme uses less hardware components and has higher dynamic performance in variable speed DC drive applications.

• Journal of Power Electronics
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• 제12권2호
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• pp.249-257
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• 2012

An interleaved PWM converter is proposed to implement the features of zero voltage switching (ZVS), load current sharing and ripple current reduction. The proposed converter includes two ZVS converters with a common clamp capacitor. With the shared capacitor, the charge balance of the two interleaved parts is automatically regulated under input voltage and load variations. The active-clamping circuit is used to realize the ZVS turn-on so that the switching losses on the power switches are reduced. The ZVS turn-on of all of the switching devices is achieved during the transition interval. The interleaved pulse-width modulation (PWM) operation will reduce the ripple current and the size of the input and output capacitors. The current double rectifier (CDR) is adopted in the secondary side to reduce output ripple current so that the sizes of the output chokes and capacitor are reduced. The circuit configuration, operation principles and design considerations are presented. Finally experimental results based on a 408W (24V/17A) prototype are provided to verify the effectiveness of the proposed converter.

• KIEE International Transactions on Electrophysics and Applications
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• 제2C권6호
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• pp.304-308
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• 2002

We demonstrate a simple pulsed $CO_2$ laser with millisecond long pulse duration in a tube at a low pressure of less than 30 Torr. The novel power supply for our laser system switches the voltage of the AC power line (60Hz) directly. The power supply doesn't need elements such as a rectifier bridge, energy-storage capacitors, or a current-limiting resistor in the discharge circuit. To control the laser output power, the pulse repetition rate is adjusted up to 60Hz and the firing angle of SCR(Silicon Controlled Rectifier) gate is varied from 30。 to 150。. A ZCS (Zero Crossing Switch) circuit and a PIC one-chip microprocessor are used to control precisely the gate signal of the SCR. The maximum laser output of 35 W is obtained at a total pressure of 18 Torr, a pulse repetition rate of 60 Hz, and a SCR gate firing angle of 90。 . In addition, the resulting laser pulse width is approximately 3㎳(FWHM). This is a relatively long pulse width, compared with other repetitively pulsed $CO_2$ lasers.