• 전기학회논문지
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• 제56권5호
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• pp.898-904
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• 2007

This paper presents the generalized and explicit expressions for evaluating the performance of the multi-phase interleaved boost converter (IBC) operating in discontinuous inductor current mode (DICM). The full order averaged model is derived. The generalized transfer functions of interest are presented and the dynamic characteristics are analyzed. The generalized analysis of converter performance is verified through the experimental and simulation results.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 II
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• pp.1019-1022
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• 2003

This paper has proposed a 4- bit 20MHz Flash A/D converter design available analog signal processing and realized its intergrated circuit. The parallel comparison method A/D converter quantized analog signals swiftly using various converters. Also this theme has designed economic power dissipation circuit using a preamplifier of low volt & power CMOS comparator. Also the system was fabricated by Hynix 0.35um CMOS process.

• ETRI Journal
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• 제29권6호
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• pp.835-837
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• 2007

A multi-bit sigma-delta modulator architecture is described for low-distortion performance and a high-speed operation. The proposed architecture uses both a delayed code and a delayed differential code of analog-to-digital converter in the feedback path, thereby suppressing signal components in the integrators and relaxing the timing requirement of the analog-to-digital converter and the scrambler logic. Implemented by a 0.13 ${\mu}m$ CMOS process, the sigma-delta modulator achieves high linearity. The measured spurious-free dynamic range is 89.1 dB for -6 dBFS input signal.

• 한국인터넷방송통신학회논문지
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• 제21권6호
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• pp.49-55
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• 2021

최근 소형 추적 레이더는 다양한 환경에서 표적을 획득하고, 추적하여 한 번의 타격으로 표적의 시스템을 무능화 시킬 수 있는 높은 거리해상도를 갖는 소형 밀리미터파 추적 레이더 개발을 요구한다. 높은 거리해상도를 갖는 소형 밀리미터파 추적 레이더는 넓은 대역폭의 신호를 실시간으로 처리하고, 소형 추적 레이더의 성능 요구 조건을 충족할 수 있는 신호처리기의 구현이 필요하다. 본 논문에서는 소형 밀리미터파 추적 레이더의 신호처리기 역할과 기능을 수행할 수 있는 신호처리기를 설계하였다. 소형 밀리미터파 추적 레이더를 위한 신호처리기는 8채널에서 입력되는 OOOMHz의 중심주파수와 OOOMHz 대역폭의 신호를 실시간으로 처리하기를 요구한다. 신호처리기의 요구사항을 만족하기 위해 고성능 프로세서 및 ADC (Analog-to-digital converter) 적용과 FPGA (Field Programmable Gate Array)를 활용한 DDC (Digital Down Converter), FFT (Fast Fourier Transform) 등의 전처리 연산을 적용하여 신호처리기를 설계하였다. 마지막으로 소형 밀리미터파 추적 레이더를 위한 신호처리기의 성능시험을 통하여 구현한 신호처리기를 검증하였다.

• 한국정보통신학회논문지
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• 제14권12호
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• pp.2628-2635
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• 2010

본 논문에서는 차량용 FMCW(Frequency Modulated Continuous Wave) 레이더의 도플러 주파수와 아날로그-디지털 변환기 비트 수에 따른 탐지 성능 분석 및 신호처리부 개발을 진행하고자 한다. 성능 평가를 위한 FMCW 레이더의 시스템 모델은 송신부와 수신부로 구성되어 있으며 채널은 가우시안 잡음 환경을 사용한다. 이론과 시뮬레이션을 통해서 시스템 모델을 검증한다. 수신부에서는 수신 신호와 기준 신호사이의 부정합으로 인한 주파수 오차가 발생하게 된다. 75cm의 분해능를 갖는 FMCW 레이더에서 도플러 주파수가 약 38KHz이하인 경우 탐지 성능의 열화가 발생하지 않음을 알 수 있다. 아날로그-디지털 변환기 비트에 따른 탐지 성능은 6비트가 최소의 비트로 결정될 수 있음을 알 수 있다. 그리고 FPGA를 이용하여 디지털 송신 파형 발생기를 위한 집적 디지털 신디사이저(Direct Digital Synthesis) 칩을 기반한 FMCW 레이더 신호처리부를 설계 및 구현을 진행한다.

• Journal of Electrical Engineering and Technology
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• 제6권3호
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• pp.375-383
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• 2011

This paper describes a real-time hardware simulator for a grid-tied Permanent Magnet Synchronous Generator (PMSG) wind power system, which consists of an anemometer, a data logger, a motor-generator set with vector drive, and a back-to-back power converter with a digital signal processor (DSP) controller. The anemometer measures real wind speed, and the data is sent to the data logger to calculate the turbine torque. The calculated torque is sent to the vector drive for the induction motor after it is scaled down to the rated simulator power. The motor generates the mechanical power for the PMSG, and the generated electrical power is connected to the grid through a back-to-back converter. The generator-side converter in a back-to-back converter operates in current control mode to track the maximum power point at the given wind speed. The grid-side converter operates to control the direct current link voltage and to correct the power factor. The developed simulator can be used to analyze various mechanical and electrical characteristics of a grid-tied PMSG wind power system. It can also be utilized to educate students or engineers on the operation of grid-tied PMSG wind power system.

• 한국산업융합학회 논문집
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• 제20권2호
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• pp.115-124
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• 2017

This paper aims to develop an SMPS topology for handling a high range of input voltages based on a DC-DC flyback converter circuit. For this purpose, 2 capacitors of the same specifications were serially connected on the input terminal side, with a flyback converter of the same circuit configuration serially connected to each of them, so as to achieve high input voltage and an effect of dividing input voltage. The serially connected flyback converters have the transformer turn ratio of 1:1, so that each coil is used for the winding of a single transformer, which is a characteristic of doubly-fed configuration and enables the correction of input capacitor voltage imbalance. In addition, a pulse transformer was designed and fabricated in a way that can achieve the isolation and noise robustness of the PWM output signal of the PWM controller that applies gate voltage to individual flyback converter switches. PSIM simulation was carried out to verify such a structure and confirm its feasibility, and a 100W class stack was fabricated and used to verify the feasibility of the proposed high voltage SMPS topology.

• 전력전자학회논문지
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• 제25권6호
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• pp.442-450
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• 2020

A small-signal modeling approach for a three-level boost (TLB) converter and a design methodology for a double-loop controller are proposed in this study. Conventional modeling of TLB converters involves three state variables. Moreover, TLB converters have two operation modes depending on the duty ratio. Consequently, complex mathematical calculations are required for controller design. This study proposes a simple system modeling method that uses two state variables, unlike previous methods that require three state variables. Analysis shows that the transfer functions of the two operation modes can be expressed as identical equations. This condition means that the linear feedback controller can be applied to all operational ranges, that is, for full duty ratios. The design method for a double-loop controller using a PI controller is presented in step-by-step sequences. Simulation and experimental verifications are conducted to verify the effectiveness of the small-signal analysis and control system design.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(2)
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• pp.610-614
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• 2004

Recently, an active-clamp, full-bridge boost converter has been actively studied for high-power applications such as power factor correction and battery discharger. However, DC and AC modeling for this converter has not conquered. In this paper, a DC and small-signal AC modeling for the active-clamp, full-bridge boost converter is described. Based on the operation principle, the ac part of the converter can be replaced by a do counterpart. Then, a conceptual equivalent circuit is derived by rearranging the switches. The equivalent circuit for this converter consists of CCM (Continuous conduction mode) boost and DCM (Discontinuous conduction mode) buck converter. The analyses for the equivalent CCM boost and DCM buck converter are done using the model of PWM switch. The theoretical modeling results are confirmed through experiment or SIMPLIS simulation.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 하계학술대회 논문집
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• pp.478-480
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• 2008

On this paper, digitally controlled push-pull dc-dc converter and dc-ac inverter for induction motor control are presented, which is used one DSP(digital signal processor). This system has 12V battery input for the push-pull converter, and the push-pull converter generates 300V output for induction motor inverter input. In order to compensate the push-pull converter, the transfer function of push-pull converter is derived and digital PI compensator is adapted. Through bode diagram, stability of digital controlled push-pull converter is analyzed. To verify the proposed system, digital simulation of the induction motor drive using digital push-pull converter are performed.