• 한국태양에너지학회 논문집
• /
• 제29권2호
• /
• pp.1-7
• /
• 2009

Use of the PV(photovoltaic) generation system is increased in such areas as remote mountain places or islands at which electrical energy is not serviced. The stand alone PV system is required the power storage products such as battery, fly wheel and super capacitor. Several lead storage batteries are connected in series to get high voltages. The life of lead storage battery is shortened when over charge or over discharge takes place. So, it is needed to control batteries not to be overcharged or be discharged deeply. Voltage of each battery was ignored in former control methods in which overall voltage was used to control charge or discharge battery. In this study, the charging and discharging voltage variations of sealed lead storage batteries with l2V/l.2A were investigated step by step experiments. The results of the test show that one should consider and specify the state of each battery to prevent overcharge or deep discharge. With the basis of the experiments, we designed a monitoring unit to monitor battery voltages simultaneously using micro-controller. The unit measures voltage of 20 batteries simultaneously and displays data on the color LCD monitor with curved line graph. It also sends data to PC using the RS232C communication port. The designed unit was adapted to stand alone PV system with 1kW capacity and lead storage batteries are connected to the PV generation system. The number of lead storage batteries was 10 in series and 12V/250Ah each. Resistive load with 3kW was used for discharging.

• 문화기술의 융합
• /
• 제9권3호
• /
• pp.727-730
• /
• 2023

전세계적으로 온실가스 및 미세먼지 저감을 위한 탄소중립 정책에 따라 전기차보급이 확대될 전망이다. 전기자동창의 운용은 열악한 환경에서 사용되고 충전과 방전 등을 거듭할수록 에너지밀도가 낮아지고 내부분리막의 손상등의 이유로 건전성이 떨어짐에 따라 차량의 주행거리가 줄고, 충전 속도가 느려지는 이유로 대략 5~10년 정도 사용한 배터리들은 폐배터리로 분류하며 이 같은 이유로 배터리 화재 및 폭발 등의 위험성이 높아 지게 됩에 따라 배터리의 진단 및 SOH의 추정이 필수적이라 할 수 있다. 배터리 SOH추정은 매우 중요한 요소로 현재는 배터리 충방전을 반복하면서 소요되는 시간, 온도, 전압을 측정하여 배터리의 상태를 평가하는데 정확도가 낮다. 불안정한 폐배터리를 다수의 반복적 충전과 방전을 통해 진단하는 과정에서 화재 및 폭발의 취약점을 보완하여 신뢰성이 높은 폐배터리의 상태데이터를 취득할 수 있는 기반을 마련하고 본 논문에서는 리튬이온 배터리의 SOH예측을 위해 테슬라 폐배터리를 이용한 방전 용량 측정을 바탕으로 획득한 데이터를 서포트 벡터 머신 기반으로 예측하고자 하였다.

• 한국정보전자통신기술학회논문지
• /
• 제14권1호
• /
• pp.91-97
• /
• 2021

전기자동차를 이용하여 계통에 전력을 공급하는 Vehicle to Grid(V2G)의 구현을 위한 통신표준으로 ISO/IEC 15118이 적용되고 있다. 통신 프로토콜에 기반을 두는 전기자동차의 충방전 제어 시에 필연적으로 충방전 실행까지의 시간지연이 발생하게 되는데, 이러한 시간지연은 전력 유연성 공급 측면에서 제한의 요인이 된다. 본 연구에서는 ISO/IEC 15118 기반 V2G 에뮬레이터를 구현하고 전기 자동차 충방전 제어에 따른 반응성을 확인하였다. 실험결과 시간지연은 0.12ms로 나타났으며, 이를 기반으로 현 표준 하에서 참여 가능한 전력 유연성 시장에 대하여 검토하였다.

• 조명전기설비학회논문지
• /
• 제22권10호
• /
• pp.8-17
• /
• 2008

본 논문에서는 선박용 HID조명의 방전 개시전압을 조절함으로써 초기 방전전류를 억제하여, HID조명의 안정적인 점등이 가능한 제어방식을 제안하였다. 제안된 제어 방식은 방전 대기전압까지 출력전압을 상승시킨 후, 충전전압의 저항부하 방전을 통하여 전압을 감소시키면서, 설계된 방전개시전압시점에서 이그니터를 점화하여 방전 개시 전류를 제한한다. 방전 후 정상상태에서는 정전류 제어로 조도를 제어하게 된다. 제안된 방식은 별도의 전압제어기를 포함하지 않으면서도, 방전개시 시점을 조절할 수 있으므로, 초기 방전 전류를 크게 제한할 수 있으므로, 안정적인 점등과 조명의 수명을 확대할 수 있는 장점이 있다. 또한 조명의 이상상태를 간단한 이상검출 회로를 통하여 순시적으로 감시하여 전체 시스템의 보호 성능을 개선하였다. 제안된 제어기는 실제 선박용 2.5[kW]급의 HID 탐사조명에 대한 실험을 통하여 검증하였다.

• 한국초전도ㆍ저온공학회논문지
• /
• 제22권3호
• /
• pp.13-19
• /
• 2020

This study presents the experiment and simulation results on the magnetic field response and electrical stability behaviors of no-insulation (NI) and metal insulation with stainless steel tape (MI-SS) which wound in form of racetrack type coils. First of all, the structural design of the racetrack type bobbin was shown along with its parameters. Then, the current-voltage tests were carried out to measure the critical current of both test coils. Also, the sudden discharging and charging tests were performed in the steady state to estimate the decay field time and magnetic field response, respectively. Finally, the overcurrent tests were conducted in the transient state to investigate the electrical stability of these test coils. Based on the experimental results, the contact surface resistances were calculated and applied to the field coils (FCs) of 10-MW-class second generation high temperature superconducting generator (2G HTSG) used in wind offshore environment. The charging delay time and electrical stability for NI and MI-SS HTS FCs of 10-MW-class 2G HTSG are analyzed by the equivalent circuit model and the key parameters which were obtained from the electromagnetic finite element analysis results.

• 전기학회논문지
• /
• 제66권1호
• /
• pp.55-60
• /
• 2017

Capacitor Charging Power Supply(CCPS) is one of the most important components of a pulsed power system. The CCPS is widely used in source of lasers, accelerators and plasma generators. This paper presents design of a dead time control circuit and operation characteristics for stable high repetition rate of high voltage CCPS. The CCPS consists of battery, high voltage transformer and controller with a dead time control circuit. A dead time control circuit was simulated by PSpice. The performance test of the CCPS was carried out with a 7[nF] load capacitor at output voltage of 50[kV] and a pulse repetition frequency of 100[Hz]. As a result, we can verify that charging and discharging waveform is stable at 100[Hz]. The experiment results indicate that 3[ms] dead time made it possible for stable high repetition rate of 100[Hz]. This paper paves the way for designing an advanced CCPS which is more applicable outside experiments.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1995년도 추계학술대회 논문집
• /
• pp.365-368
• /
• 1995

Charge decay, thermally stimulated current (TSC), charging and discharging currents(I) are measured for corona-charged composite insulating materials. In this study, We will make an experiment in charge decay on composite material surface, TSC, polarity effect and the others in order to analysis its mechanism. Especially, Fiber glass Reinforced Plastics(FRP) is the best composite material which has been so far. Therefore, Its worthy of notice to investigate its characteristic. And then some other materials will be focused on. This experiment measured characteristic of charge decay, dependence of discharging-time and other electrostatic characteristics on FRP.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
• /
• pp.565-568
• /
• 2002

The value of charge current, discharge current, $\varepsilon_r$' $\varepsilon_r"$, residual voltage was measured inorder to investigate electric properties in Ethylene Prophylene Rubber for is irradiated $CO^{60}\gamma$ ray 0-38.1 Mrad. The value of charge current and the discharging current of the EPR is influenced by $CO^{60}-{\gamma}$-irradiation dose The charging current and the discharging current of EPR increase, depending on the ratio of degradation. As the irradiation dose is increased, the peak of residual voltage moves to the slorter time. The properties specific electric constant due to time variation was appeared dispersion by plentiful $CO^{60}-{\gamma}$-irradiation dose. The increase of peak in $\varepsilon_r"$ is attrib uted to the irratiation dose almost proportionally.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2008년도 하계학술대회 논문집
• /
• pp.277-279
• /
• 2008

In this paper, a novel active boost converter for SR drive is proposed. An active capacitor circuit is added in the front-end. Based on this active capacitor network, when boost switch turns off, this network seems as passive capacitor network. And the voltage of boost capacitor can keep balance with dc-link voltage automatically. In the capacitor network, discharging voltage is general dc-link voltage in parallel-connected capacitors; charging voltage is double dc-link voltage in series-connected capacitors. When boost switch turns on, two capacitors are connected in series, and discharging voltage is up to double dc-link voltage. So the fast excitation current can be obtained from this mode. Profit from fast excitation and fast demagnetization mode, the performance and output power can be improved. Some computer simulations are done to verify the performance of proposed converter.

• 대한전기학회논문지
• /
• 제32권7호
• /
• pp.227-233
• /
• 1983

Noticing that action of gaseous phase in insulating oil concerns to the discharging characteristics, I investigated the smalness pressure effects on quantity of the partial discharge and discharging pulse frequency. Tests are carried out between the niddle points in insulating oil at pressure being changed by gradual charge of inert gas Ar. At pressure as low as of 0.1-0.5 torr pulse frequency and maximum partial discharge reach peak while at pressure haigher than 20 torr no pulse is observed. The fact that pulse frequency has peak value at certain presure, which is changed either by charging Ar or by adding oil, implies that the action of gaseous phase depends on pressure. Test results are that partial discharge pulse are governed by pressure of Ar-charged oil, and less partial discharge pulses correspond to smaller bubbles whereas more partial descharge pulses correspond to larger bubbles.