• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.274-275
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• 2017

부스트-인버터 시스템에서 6-스텝 시 토크 리플을 줄이기 위한 방법을 제시한다. 모델 기반의 전압 방정식을 통해 필요한 직류단 전압의 크기 및 위상을 구하고 전류 전향 보상을 통해 전압을 합성한다. 이를 통해 직류단 캐패시턴스를 수 ${\mu}F$까지 낮출 수 있어 캐패시터의 부피 및 비용을 절감할 수 있다. 이러한 최적 해 운전 시 생기는 입력 파워 리플의 문제점을 해결하기 위한 일정 파워 공급 방법을 제시하며 이를 통해 운전영역에 따른 적절한 운전 방법의 선택을 제시한다.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2318-2320
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• 2005

In this paper, a low noise amplifier(LNA) in a receiver of a Low Noise Block Down Converter (LNB) for direct broadcasting service(DBS) is implemented using GaAs HEMT. The LNA is designed for the bandwidth of 11.7GHz-12.2GHz. The 2stage-LNA consists of a input matching circuit, a output matching circuit, DC-blocks and RF-chokes. The result of a simulation of the LNA using Advanced Design System(ADS) shows the noise figure less than 1.4dB, the gain greater than 23dB and the flatness of 1dB in the bandwidth of 11.7 to 12.2GHz.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.217-221
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• 2006

Offline switching Power supplies have high voltage and high current switching waveforms that generate Electromagnetic Interference(EMI) in the form of both conducted and radiated emissions. Consequently, all off-line power supplies must be designed to attenuate or suppress EMI emissions below commonly acceptable limits. Electrodeless fluorescent lamp's ballasts have AC/DC flyback converter, so we must control the EMI emissions.

• Journal of Power Electronics
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• v.3 no.4
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• pp.224-229
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• 2003

The rapid expansion of small computers over the last 10-odd years has brought about great changes in the circumstances affecting UPSs. There are strong demands that UPSs become much smaller and lighter, and more economical, which has resulted in the wide application of the circuit topology without transformer. A disadvantage of such UPS topology is that the DC link voltage is very high, which invites decreased reliability and increased cost of battery bank. Some circuit configurations were proposed to eliminate this disadvantage, but they still had problems. In this paper, a novel circuit configuration which eliminates these problems is proposed and evaluated by the experimental results of prototype UPS.

• Journal of Power Electronics
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• v.8 no.2
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• pp.131-140
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• 2008

This paper presents a new control approach of DSTATCOM (distribution static compensator) for compensation of reactive power, unbalanced loading and harmonic currents under unbalanced non-sinusoidal ac mains. The control of DSTATCOM is achieved using Adaline based current estimator based on LMS algorithm to maintain source currents real and undistorted. The dc bus voltage of voltage source converter (VSC) working as DSTATCOM is maintained at constant voltage using a proportional-integral (PI) controller. The DSTATCOM system alongwith proposed control scheme is modeled in MATLAB to simulate the behavior of the system. The practical implementation of the DSTATCOM is carried out using dSPACE DS1104 R&D controller having TMS320F240 as a slave DSP. Simulated and implementation results are presented to demonstrate the effectiveness of the DSTATCOM with Adaline based control to meet the severe load perturbations with different types of loads (linear and non-linear) under distorted and unbalanced AC mains.

• Journal of Power Electronics
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• v.10 no.4
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• pp.374-381
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• 2010

Typical power electronic converters employ only pulse width modulation (PWM) to generate specific switching patterns. In this paper, a novel control strategy combining both pulse-width and amplitude modulation strategies (PWAM) has been proposed for power converters. The Pulse Amplitude Modulation (PAM), used in communication systems, has been applied to power electronic converters. This increases the degrees of freedom in eliminating or mitigating harmonics when compared to the conventional PWM strategies. The role of PAM in the novel PWAM strategy is based on the control of the converter's dc sources values. Software implementation of the conventional PWM and the PWAM control strategies has been applied to a five-level inverter for mitigating selective harmonics. Results show the superiority of the proposed strategy from the THD point of view along with a reduction in the inverter power dissipation.

• Proceedings of the KIPE Conference
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• 2008.10a
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• pp.57-60
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• 2008

Recently, new technologies of the PCS (Power Conditioning System) for energy generating using solar cells or fuel cell are required for smaller unit with low cost and high performance. In this paper, the proposed high frequency AC linked DC/AC converter which consisted of LLC resonant and LF cycloconverter is presented, described and verified through the experimental results of 1kW PCS.

• Proceedings of the KIPE Conference
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• 2008.10a
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• pp.184-186
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• 2008

리니어 발전기는 리니어 엔진의 시동에 필요한 연소조건을 만들기 위하여 전동기로 동작하다가 연소가 안정화되면 발전기로 동작을 하여 PCS(Power Conditioning System)를 통해서 전력을 계통으로 보내주게 된다. 리니어 엔진의 초기 시동을 하기 위하여 발전기는 운동주파수와 운동방향, 그리고 힘의 크기를 제어해야 하며, 발전 시에는 엔진의 동작에 맞도록 전력을 제어해야 한다. 이를 효율적으로 제어하기 위하여 MSC(Machine Side Converter)에서 상전류를 독립적으로 조절할 수 있는 H-bridge로 각 상을 구성하였다. LSI(Line Side Inverter)는 DC-Link 전압을 제어하여, MSC의 동력/발전 동작에 따라서 전력을 계통에서 받아오거나 전력을 계통으로 보내는 동작을 한다. 본 연구에서는 리니어 발전기 모델링를 통해서 PCS 제어 알고리즘을 확인하고 전체 시스템과 연동을 한 실제 운전특성에 대하여 살펴보았다.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.77-78
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• 2014

기존 대용량 전원 회로는 상용 전원 조건에서 AC Line 입력 전류가 높아져 누전기가 차단되는 문제가 있다. 그 뿐만 아니라 입력 전류가 높아지면 기존 전력 설비 용량이 부족한 경우가 발생하여, 전력 설비 교체 등 공사의 필요가 있다. 따라서 기존의 전력 설비를 그대로 이용하면서 단상 AC 전원의 허용 한계를 넘는 대용량 전력을 구동할 수 있는 방안을 제안한다. 역률개선회로에 전력 제한 기능을 구현하여 입력 전류를 제한하는 방법과 부족한 전력을 배터리 충/방전 회로를 이용해 보충하는 방안을 제안하며, 제안된 회로의 분석을 수행하고, 1.2KW 급 시작품을 이용한 실험적 분석을 통해 그 가능성을 검증한다.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.341-342
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• 2014

VSC-HVDC system based on Modular Multilevel Converter (MMC) is an emerging technology since compared to the conventional VSC-HVDC system an MMC presents several advantages such as modularity, low dv/dt, low harmonics, and low switching losses. In this paper, a comprehensive control strategy of an MMC-based VSC-HVDC system is proposed. In contrast to the conventional system control strategy, the DC side of the MMC operates as a controlled voltage source by the proposed method, and the dynamics of the transmission line voltage and current can be actively controlled. Validity of the proposed strategy was verified by 201-level full-scale computer simulation.