• Journal of Power Electronics
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• 제16권2호
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• pp.399-413
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• 2016

This paper presents a topology for a modular power electronic transformer (PET) and a control scheme. The proposed PET consists of a cascaded H-Bridge rectifier on the primary side, a high-frequency DC/DC conversion cell in the center, and a cascaded H-Bridge inverter on the secondary side. It is practical to use PETs in power systems to reduce the cost, weight and size. A detailed analysis of the structure is carried out by using equivalent circuit. An algorithm to control the voltages of each capacitor and to maintain the power flow in the PET is established. The merits are analyzed and verified in theory, including the bi-directional power flow, variable voltage/frequency and high power factor on the primary side. The experimental results validated the propose structure and algorithm.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.195-197
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• 2005

This paper proposed the new harmonic detection system for the source current with the large frequency variation. The harmonic detection system is designed of the analog circuit and is composed of a low pass filter, a DC-level converter using the PLL, the Voltage controlled GIC.

• Journal of electromagnetic engineering and science
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• 제6권1호
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• pp.18-23
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• 2006

In this paper, we demonstrate a fully integrated X-band image rejection down converter, which was developed using InGaP/GaAs HBT MMIC technology, consists of two single-balanced mixers, a differential buffer amplifier, a differential YCO, an LO quadratue generator, a three-stage polyphase filter, and a differential intermediate frequency(IF) amplifier. The X-band image rejection downconverter yields an image rejection ratio of over 25 dB, a conversion gain of over 2.5 dB, and an output-referred 1-dB compression power$(P_{1dB,OUT})$ of - 10 dBm. This downconverter achieves broadband image rejection characteristics over a frequency range of 1.1 GHz with a current consumption of 60 mA from a 3-V supply.

• Journal of Power Electronics
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• 제16권5호
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• pp.1939-1949
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• 2016

This paper presents an alternative frequency adaptive grid synchronization technique named HDN-FLL, which can accurately extract the fundamental positive- and negative-sequence components and interested harmonics in adverse three-phase grid voltage. The HDN-FLL is based on the harmonic decoupling network (HDN) consisting of multiple first order complex vector filters (FOCVF) with a frequency-locked loop (FLL), which makes the system frequency adaptive. The stability of the proposed FLL is strictly verified to be global asymptotically stable. In addition, the linearization and parameters tuning of the FLL is also discussed. The structure of the HDN has been widely used as a prefilter in grid synchronization techniques. However, the stability of the general HDN is seldom discussed. In this paper, the transfer function expression of the general HDN is deduced and its stability is verified by the root locus method. To show the advantages of the HDN-FLL, a simulation comparison with other gird synchronization methods is carried out. Experimental results verify the excellent performance of the proposed synchronization method.

• 전자공학회논문지
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• 제53권5호
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• pp.152-159
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• 2016

본 논문은 CMOS 자기센서(hall Sensor)의 오프셋 및 1/f 잡음 제거기술 기반 고선형 자기센서 신호처리장치를 제안한다. 제안하는 자기센서는 자계(magnetic Field)를 감지하여 자계의 변화량에 따른 홀 전압(hall Voltage)을 출력하는 홀 플레이트(hall Plate)와 홀 플레이트 출력 신호의 오프셋과 1/f 잡음 제거 및 디지털화를 위한 자기센서 신호처리시스템으로 구성된다. 자기센서 신호처리 시스템은 스피닝 전류 바이어싱(spinning current biasing)을 통해 자기신호로부터 오프셋과 1/f잡음 성분을 분리하고, 초퍼 및 증폭기를 통해 자기신호를 100 kHz 주파수 대역으로 변조한다. 60 kHz 차단주파수를 갖는 고역통과필터(highpass filter)를 사용하여 오프셋 및 1/f 잡음을 제거한뒤 ADC(analog to digital converter)를 통해 자기신호만을 디지털 변조한다. 증폭기 및 고역통과필터 출력은 자기신호 -53.9 dBm @ 100 kHz, 잡음성부은 -101.3 dBm @ 10 kHz이다. 최종적으로 ADC를 통과한 자기센서 출력은 -5.0 dBm @ 100 kHz이고, 오프셋 및 1/f 잡음은 -55.0 dBm @ 10 kHz이다.

• 센서학회지
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• 제6권3호
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• pp.194-199
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• 1997

자기센서가 전압이나 전류의 형태 그대로 출력되는 경우에 발생되는 잡음 유입 및 전압 손실 문제를 개선하기 위하여 소자부는 CMOS공정을 이용하여, 포화영역에서 동작하는 2 drain의 MAGFET을 설계 제작하고, 연산증폭기를 이용한 I-V변환회로, VCO(Voltage Controlled Oscillator)를 만들고 Schmitt trigger에 의한 주파수(Pulse) 변환회로의 시스템부를 하이브릿드 IC로 구성하여 packaging했다. 이 때 자기센서 절대감도는 1.9 V/T, 적감도는 $3.2{\times}10^{4}\;V/A{\cdot}T$ 이었으며 190 kHz/T의 안정된 출력 주파수 특성을 얻을 수 있었다.

• 전력전자학회논문지
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• 제18권2호
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• pp.169-177
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• 2013

This paper proposes a new configuration of bidirectional intelligent semiconductor transformer with rating of 1.9kV/127V, 2kVA. The proposed transformer consists of high-voltage high-frequency AC-DC rectifier, and low-voltage DC-DC and DC-AC converters. The operational feasibility of proposed transformer was verified by computer simulation with PSCAD/EMTDC software. Based on the simulation results, a hardware prototype with rating of 1.9kV/127V, 2kVA was built and tested in the lab to confirm the feasibility of hardware implementation. Using three units of this transformer, a 3-phase transformer with rating of 3.3kV/220V, 6kVA can be built.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.463-464
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• 2008

As the demands of LCD and PDP TV are increasing, the high performance HVICs(High Voltage Gate Driver ICs) technology is becoming more necessary. In this paper, we designed the HVIC that has enhanced noise immunity and high driving capability. It can operate at 500KHz switching frequency and permit 600V input voltage. High-side level shifter is designed with noise protection circuit and schmitt trigger. Therefore it has very high dv/dt immunity, the maximum being 50V/ns. The HVIC was designed using $1{\mu}m$ BCD 650V process and verified by Spectre and PSpice of Cadence inc. simulation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1488-1490
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• 2008

The gyroscope is the sensor for detecting the rotation in inertial reference frame and constitute the navigation system together an accelerometer. As the inertial reference equipment for attitude determination and control in the satellite, the mechanical gyroscope has been used but it bring the disturbance for mass unbalance so the disturbance give a bad influence to the observation satellite mission because the mechanical gyroscope has the rotation parts. During the launch, The mechanical gyroscope is weak in vibration, shock and has the defect of narrow operating temperature range so it need the special design in integration. Recently the low orbit observation satellite for seeking the high pointing accuracy of image camera payload accept the FOG(Fiber Optic Gyro) or RLG(Ring Laser Gyro) for the attitude determination and control. The Ring Laser Gyro makes use of the Sanac effect within a resonant ring cavity of a He-Ne laser and has more accuracy than the other gyros. It need the 1000V DC to create the He-Ne plasma in discharge tube. In this paper, the design process of the High Voltage Power Supply for RLG(Ring Laser Gyroscope) is described. The specification for High Voltage Power Supply(HVPS) is proposed. Also, The analysis of flyback converter topology is explained. The Design for the HVPS is composed of the inverter circuit, feedback control circuit, high frequency switching transformer design and voltage doubler circuit.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2017년도 전력전자학술대회
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• pp.18-19
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• 2017

This paper shows the design of the high voltage capacitor charger which using a modified series parallel resonant converter. The used silicon carbide Metal-Oxide Semiconductor Field Effect Transistor (SiC MOSFET) is proper for the few hundred kHz of high switching frequency to overcome the bulk resonant inductor and snubber capacitors. Furthermore, to increase the amount of the charging current, three phase delta transformer is used as well as the secondary sides are connected in parallel. In this paper, the design procedure of the high voltage capacitor charger is suggested and the output power is verified by the experimental results with the rated resistor load.