• 한국정보전자통신기술학회논문지
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• 제13권3호
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• pp.184-196
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• 2020

본 논문에서는 배터리 관리 시스템 (BMS)에서 2차 전지 배터리를 통해 흐르는 전류의 정밀한 측정을 위한 cascaded-of-integrator feedforward (CIFF) 구조의 단일 비트 2차 델타-시그마 모듈레이터를 제안하였다. 제안된 모듈레이터는 2개의 스위치드 커패시터 적분기, 단일 비트 비교기, 비중첩 클록 발생기 및 바이어스와 같은 주변 회로로 구현하였다. 제안된 구조는 낮은 공통 모드 입력 전압을 가지는 low-side 전류 측정 방법에 적용되도록 설계되었다. Low-side 전류 측정 방법을 사용하면 회로 설계에 부담이 줄어들게 되는 장점을 가진다. 그리고 ±30mV 입력 전압을 15비트 해상도를 가지는 ADC로 분해하기 때문에 추가적인 programmable gain amplifier (PGA)를 구현할 필요가 없어 수 mW의 전력소모를 줄일 수 있다. 제안된 단일 비트 2차 CIFF 델타-시그마 모듈레이터는 350nm CMOS 공정으로 구현하였으며 5kHz 대역폭에 대해 400의 oversampling ratio (OSR)로 95.46dB의 signal-to-noise-and-distortion ratio (SNDR), 96.01dB의 spurious-free dynamic range (SFDR) 및 15.56비트의 effective-number-of-bits (ENOB)을 달성하였다. 델타 시그마 모듈레이터의 면적 및 전력 소비는 각각 670×490㎛2 및 414㎼이다.

• 한국정보통신학회논문지
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• 제4권5호
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• pp.1117-1125
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• 2000

벅 컨버터 회로 평균모델를 이용하고 한주기 응답 기법을 적용한 전류모드 PWM 기법을 제안하였다. 이 제어기는 비선형 PWM 제어기로 스위칭 변수와 응답 기준과의 오차를 각 주기에서 0이 되도록 구현하였다. 그 결과, 시스템 전달함수는 폐루프 극점의 함수가 되어 설계가 용이하며 폐루프 특성이 향상되었다. 이 제어기에서 인덕터 전류의 상태 변수를 구현하기 위하여 전류모드를 이용하여 컨버터를 제어하였다. 제안한 PWM제어는 인덕터 전류 센서를 생략할 수 있으며 잡음 특성, 동특성이 기존 전류 모드 제어기에 비하여 많은 장점을 갖는다. 시뮬레이션 및 실험을 통하여 타당성을 입증하였다.

• 전기학회논문지
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• 제64권9호
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• pp.1315-1322
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• 2015

This paper proposes an active islanding detection method for the BESS (Battery Energy Storage System) with 3-phase inverter which is connected to the AC grid. The proposed method adopts the DDSRF (Decoupled Double Synchronous Reference Frame) PLL (Phase Locked-Loop) so that the independent control of positive-sequence and negative-sequence current is successfully carried out using the detected phase angle information. The islanding state can be detected by sensing the variation of negative-sequence voltage at the PCC (Point of Common Connection) due to the injection of 2-3% negative-sequence current from the BESS. The proposed method provides a secure and rapid detection under the variation of negative-sequence voltage due to the sag and swell. The feasibility of proposed method was verified by computer simulations with PSCAD/EMTDC and experimental analyses with 5kW hardware prototype for the benchmark circuit of islanding detection suggested by IEEE 1547 and UL1741. The proposed method would be applicable for the secure detection of islanding state in the grid-tied Microgrid.

• Nuclear Engineering and Technology
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• 제52권11호
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• pp.2535-2542
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• 2020

To understand the fundamental parameters of Alvand tokamak, A Rogowski coil with an active integrator was designed and constructed. Considering the characteristics of the Alvand tokamak, the structural and electrical parameters affecting the sensor function, were designed. Calibration was performed directly in the presence of plasma. The sensor has a high resistance against interference of external magnetic fields. Plasma current was measured in various experiments. Based on the plasma current profile and loop voltage signal, the time evolution of plasma discharge was investigated and plasma behavior was analyzed. Alvand tokamak discharge was divided into several regions that represents different physical phenomena in the plasma. During the plasma discharge time, plasma had significant changes and its characteristic was not uniform. To understand the plasma behavior in each of the phases, the Rogowski sensor should have sufficient time resolution. The Rogowski sensor with a frequency up to 15 kHz was appropriate for this purpose.

• Journal of Information Display
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• 제13권3호
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• pp.119-123
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• 2012

In this work, we report on a new monitoring method for an organic light-emitting diode (OLED) panel for lighting by optical sensing of the wave-guided light in the substrate. Using microlens array films, the wave-guided light was extracted into the edge or back side of the panel to be monitored by a photodiode. The luminance of the extracted light was measured as linearly proportional to the front light. Thus, by converting the extracted light into photo voltage, monitoring the luminance change occurring in the OLED is possible. Based on the results and concepts, we have proposed a photodiode-equipped driving circuit which can generate compensated driving current for uniform luminance of OLED panels.

• 제어로봇시스템학회논문지
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• 제20권10호
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• pp.1051-1056
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• 2014

In this paper, we introduce an intelligent robotic arc welding system which exploits sensors like as LVS (Laser Vision Sensor), Hall effect sensor, voltmeter and so on. The use of industrial robot is saturated because of its own limitation, and one of the major limitations is that industrial robot cannot recognize the environment. Lately, sensor-based environmental awareness research of the industrial robot is performed actively to overcome such limitation, and it can expand application field and improve productivity. We classify the sensor-based intelligent arc welding robot system by the goal and the sensing data. The goals can be categorized into detection of a welding start point, tracking of a welding line and correction of a torch deformation. The Sensing data can be categorized into welding data (i.e. current, voltage and short circuit detection) and displacement data (i.e. distance, position). This paper covers not only the explanation of the each category but also its advantage and limitation.

• ETRI Journal
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• 제45권4호
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• pp.570-580
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• 2023

Sensor nodes are the most significant part of a wireless sensor network that offers a powerful combination of sensing, processing, and communication. One major challenge while designing a sensor node is power consumption, as sensor nodes are generally battery-operated. In this study, we proposed the design of a low-power, long range-based wireless sensor node with flexibility, a compact size, and energy efficiency. Furthermore, we improved power performance by adopting an efficient hardware design and proper component selection. The Nano Power Timer Integrated Circuit is used for power management, as it consumes nanoamps of current, resulting in improved battery life. The proposed design achieves an off-time current of 38.17309 nA, which is tiny compared with the design discussed in the existing literature. Battery life is estimated for spreading factors (SFs), ranging from SF7 to SF12. The achieved battery life is 2.54 years for SF12 and 3.94 years for SF7. We present the analysis of current consumption and battery life. Sensor data, received signal strength indicator, and signal-to-noise ratio are visualized using the ThingSpeak network.

• Journal of Power Electronics
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• 제8권3호
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• pp.217-227
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• 2008

The electric power subsystems (EPS) of most remote sensing satellites consist of a solar array as a source of energy, a storage battery, a power management and control (PMC) unit and a charge equalization unit (CEU) for the storage battery. The PMC and CEU use high frequency transformers in their power modules. This paper presents a design, implementation and testing results of a high frequency transformer for the EPS of satellite applications. Two approaches are used in the design process of the transformer based on the pre-determined transformer specifications. The transformer is designed based on an ETD 29 ferrite core. The implemented transformer consists of one center-tapped primary coil with eleven center-tapped secondary coils. The offline calculation results and measured values of R, L for transformer coils are convergence. A test circuit for measuring the transformer parameters like voltage, current and B-H hysteresis was implemented and applied. The test results confirm that the voltage waveforms of both primary and secondary coils were as desired. No overlapping occurred between the control signal and the transformer, which was not saturated during testing even during a short circuit test of the secondary channels. The dynamic B-H loop characteristics of the used transformer cores were measured. The sample test results are given in this paper.

• 전기전자학회논문지
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• 제27권1호
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• pp.12-18
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• 2023

각각의 큐빗(qubit)을 개별적으로 상온의 제어 회로에 연결하는 현재의 회로 기술은 양자 컴퓨터의 확장성, 신뢰성을 갖추는 데 있어 한계를 가지고 있으며, 집적도 측면에서 극저온의 CMOS 기술 기반 인터커넥트 회로 기술을 통해 기존 기술 대비 인터커넥트의 복잡도, 시스템 안정도 및 사이즈, 그리고 가격 경쟁력을 획기적으로 개선할 수 있을 것으로 기대되고 있다. 외부의 전기적 자극에 민감하며 양자 상태를 일정 시간 이상 유지할 수 없는 큐빗의 특성으로 인한 문제를 극복하고, 확장성과 신뢰성을 양자 컴퓨터 실현을 위한 CMOS 기술 기반 집적화된 센싱 및 제어 회로 기술에 대해 소개한다.

• 전기전자학회논문지
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• 제22권1호
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• pp.174-179
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• 2018

본 논문에서 저전력 PMIC를 위한 고효율 DC-DC 변환기를 설계하였다. IoT 및 웨어러블 기기의 발전에 따라 전력 공급을 위한 고효율 에너지 습득 기술이 중요해지고 있다. 에너지 습득을 통해서 얻을 수 있는 전압은 낮고 넓은 분포의 값을 가지므로 이를 사용하기 위해서 넓은 입력 전압 범위에서 고효율을 얻을 수 있는 설계 기법이 필수적이다. 넓은 입력 전압 범위에서 일정한 스위칭 주파수를 얻기 위해 전원 전압 변화 감지 회로를 이용한 주파수 보상 회로를 설계했으며, 낮은 전력에서 고효율을 얻기 위해 burst-mode 제어 회로를 구성하여 정밀한 스위칭 동작을 제어하였다. 설계한 DC-DC 벅 변환기는 0.95~3.3V의 입력 전압 조건에서 0.9V를 출력하며 부하 전류가 180uA일 때 최대 78%의 효율을 얻을 수 있다.