• 전력전자학회논문지
• /
• 제25권2호
• /
• pp.127-132
• /
• 2020

In this study, single-phase and three-level boost converters applied to the photovoltaic system were compared and analyzed in terms of efficiency and power density according to the input voltage and load conditions. For accurate analysis of efficiency, the losses in each device of the single-phase and three-level boost converters were derived using mathematical equations and simulations by using the PSIM thermal module. Then, the losses were compared with the efficiency confirmed through the actual experiments. Results confirmed that the efficiency and power density can be improved by applying the three-level boost converter to the system according to the selection of the switching frequency.

• 한국통신학회논문지
• /
• 제32권3A호
• /
• pp.319-323
• /
• 2007

본 논문에서는 50-1000 MHz의 주파수 범위에서 전력과 임피던스의 표준을 이용하여 RF전압을 자동으로 정밀 측정을 하였다. RF-DC차를 결정하기 위하여 동축형 미소열량계와 자동 회로망 분석기가 이용되었으며, 총불확도는 약 1 % 이다. 써미스터 마운트의 실효효율과 열전압 변환기의 RF-DC차를 측정하기 위하여 HP 컴퓨터와 Commodore 컴퓨터, 그리고 IEEE-488 인터페이스 버스를 이용하고, 측정하는 전체과정이 자체 개발한 프로그램에 의해 자동으로 수행되었다.

• 전기학회논문지P
• /
• 제57권3호
• /
• pp.338-342
• /
• 2008

Hybrid Electric Vehicle(HEV) is driven by an internal-combustion engine and an electric motor. It is a combination of an internal-combustion engine and several electrical equipments which use a high voltage battery, an electric motors, an inverter and others. But there is not any separate detailed enforcement regulations for high voltage electric appliances in the existing vehicle-related safety standards. So, test standards suggestion as well as test technique development need to be done for ensuring electrical safety, for an electric motor, a high voltage battery, a(n) inverter/converter and an electric power transmission units and other equipments to ensure the safety of high voltage electric appliances which is the HEV key electrical component. In this paper, We are to provide helpful data to support test technique development and test standard establishment for HEV design and electrical safety security by the following methods; by measuring the voltage, the electric current, and the frequency of HEV, by analyzing electrical characteristics of high voltage electric appliances, and by analyzing temperature characteristics of the electrical current among the analyzed electrical characteristics by thermal imagining cameras.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제17권1호
• /
• pp.29-34
• /
• 2017

A CMOS-based temperature sensor is proposed for low-voltage and low-power on-chip thermal monitoring applications. The proposed temperature sensor converts a proportional to absolute temperature (PTAT) current to a PTAT frequency using an integrator and hysteresis comparator. In addition, it operates in the subthreshold region, allowing reduced power consumption. The proposed temperature sensor was fabricated in a standard 90 nm CMOS technology. Measurement results of the proposed temperature sensor show a temperature error of between -0.81 and $+0.94^{\circ}C$ in the temperature range of 0 to $70^{\circ}C$ after one-point calibration at $30^{\circ}C$, with a temperature coefficient of $218Hz/^{\circ}C$. Moreover, the measured energy of the proposed temperature sensor is 36 pJ per conversion, the lowest compared to prior works.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제51권10호
• /
• pp.568-572
• /
• 2002

High precision voltages, currents, and electrical power measurements in wide range of frequency can be achieved by using the thermo-elements(thermal converters). This paper describes a development wattmeter, based on a thermal principle. The instrument has been performed measurement in the range of currents from 0 to 50 A, voltages up to 480 V, power factor 0.5 (lag, lead), 1 and frequencies from 60 Hz to 3 KHz. It is intended to be used by electric utilities, standard laboratories, testing laboratories, and applications where high measurement accuracy are attractive consideration.

• Journal of Power Electronics
• /
• 제5권1호
• /
• pp.55-61
• /
• 2005

A fuel cell (FC) system includes a fuel processor plus subsystems to manage air, water, and thermal energy, and electric power. The overall system is high-priced and needs peripheral devices. In this paper, a FC simulator is designed and constructed with the electrical characteristics of a fuel cell generation (FCG) system, using uses a simple buck converter to overcome these disadvantages. The characteristic voltage and current (V-I) curve for the FC simulator is controlled by a simplified linear function. In addition, to verify FCG system performance and operation, a full-bridge DC/DC converter and a single-phase DC/AC inverter were designed and constructed for FC applications. Close agreement between the simulation and experimental results confirms the validity and usefulness of the proposed FC simulator.

• 센서학회지
• /
• 제15권1호
• /
• pp.34-39
• /
• 2006

This study provides the electrical model of combustible catalytic gas sensor. Physical characteristics such as thermal behavior, resistance change were included in this model. The finite element method analysis for sensor device structure showed that the thermal behavior of sensor is expressed in a simple electrical equivalent circuit that consists of a resistor, a capacitor and a current source. This thermal equivalent circuit interfaces with real electrical circuit using two parts. One is 'power to heat' converter. The other is temperature dependent variable resistor. These parts realized with the analog behavior devices of the SPICE library. The gas response tendency was represented from the mass transferring limitation theory and the combustion theory. In this model, Gas concentration that is expressed in voltage at the model, is converted to heat and is flowed to the thermal equivalent circuit. This model is tested in several circuit simulations. The resistance change of device, the delay time due to thermal capacity, the gas responses output voltage that are calculated from SPICE simulations correspond well to real results from measuring in electrical circuits. Also good simulation result can be produced in the more complicated circuit that includes amplifier, bios circiut, buffer part.

• 한국전자파학회논문지
• /
• 제16권5호
• /
• pp.455-464
• /
• 2005

본 논문에서는 손실이 있는 전송선로의 전달 임피던스를 적용한 열전형 전압 변환기(TVC)의 모델을 제안하였으며, TVC의 교류-직류 변환 차이를 계산하기 위한 프로그램을 개발하였다. 제안된 TVC는 열전소자(TE)와 열전소자의 측정범위를 확대하기 위한 저항선이 동축형 실린더의 중심에 직선형태로 직렬로 연결되었다. 제안된 TVC의 교류-직류 변환 차이를 실린더의 직경, 열전도도 등의 특성을 적용하여 시뮬레이션 하였다. 시뮬레이션 값이 불확도 이내에서 측정값과 잘 일치하였다. 일치도는 주파수 $40Hz\~10kHz$에서는 $1{\mu}V/V$이하였고, $20kHz\~100kHz$에서는 $5{\mu}V/V$이하였으며, $200kHz\~1MHz$에서는 최대 $12{\mu}V/V$이하의 차이를 보였다.

• 센서학회지
• /
• 제10권3호
• /
• pp.196-206
• /
• 2001

열 영상 촬영에 의한 평면형 크로멜-알루멜 다중접합 열전변환기(TC 1)의 실제 온도분포를 측정하였다. 또한 유한 요소법에 의한 3차원 ANSYS 프로그램으로 열전변환기를 컴퓨터 시뮬레이션하여 열전변환기(TC 1${\sim}$TC 6)의 입력전력에 따른 온도분포를 예측하였다. TC 1의 고온 접합부 온도와 저온 접합부 온도의 차이가 가장 작고 TC 6의 고온 접합부 온도와 저온 접합부 온도의 차이가 가장 크게 나타나기 때문에 TC 1의 전압 감응도는 가장 작은 3.09 mV/mW로 측정되었고 TC 6의 전압 감응도는 가장 큰 4.03 mV/mW으로 측정되었다.

• 한국산학기술학회논문지
• /
• 제17권9호
• /
• pp.21-26
• /
• 2016

본 논문에서는 휴대 전자기기의 내부 전원단을 위한, CCM/DCM 기능의 이중모드 감압형 DC-DC 벅 컨버터를 제안한다. 제안하는 변환기는 1 MHz의 주파수에서 동작하며, 파워단과 제어블럭으로 이루어진다. 파워단은 Power MOS 트랜지스터, 인덕터, 커패시터, 제어 루프용 피드백 저항으로 구성된다. 제어부는 펄스폭 변조기 (PWM), 오차증폭기, 램프 파 발생기, 오실레이터 등으로 이루진다. 또한 본 논문에서 보상단의 큰 외부 커패시터는, 집적회로의 면적축소를 위하여 CMOS 회로로 구성되는 멀티플라이어 등가 커패시터로 대체하였다. 또한,. 본 논문에서, 보상단의 외부 커패시터는 집적회로의 면적을 줄이기 위하여 곱셈기 기반 CMOS 등가회로로 대체하였다. 또한 제안하는 회로는 칩을 보호하기 위하여 출력 과전압, 입력부족 차단 보호회로 및 과열 차단 보호회로를 내장하였다. 제안하는 회로는 $0.18{\mu}m$ CMOS 공정을 사용하여, 케이던스의 스펙트라 회로설계 프로그램을 이용하여 설계 및 검증을 하였다. SPICE 모의 실험 결과, 설계된 이중모드 DC-DC 벅 변환기는 94.8 %의 피크효율, 3.29 mV의 리플전압, 2.7 ~ 3.3 V의 전압 조건에서 1.8 V의 출력전압을 보였다.