http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Implementation of cost‐effective wireless photovoltaic monitoring module at panel level
정진두,한진수,이일우,정종화 한국전자통신연구원 2018 ETRI Journal Vol.40 No.5
Given the rapidly increasing market penetration of photovoltaic (PV) systems in many fields, including construction and housing, the effective maintenance of PV systems through remote monitoring at the panel level has attracted attention to quickly detect faults that cause reductions in yearly PV energy production, and which can reduce the whole‐life cost. A key point of PV monitoring at the panel level is cost‐effectiveness, as the installation of the massive PV panels that comprise PV systems is showing rapid growth in the market. This paper proposes an implementation method that involves the use of a panel‐level wireless PV monitoring module (WPMM), and which assesses the cost‐effectiveness of this approach. To maximize the cost‐effectiveness, the designed WPMM uses a voltage‐divider scheme for voltage metering and a shunt‐resistor scheme for current metering. In addition, the proposed method offsets the effect of element errors by extracting calibration parameters. Furthermore, a design method is presented for portable and user‐friendly PV monitoring, and demonstration results using a commercial 30‐kW PV system are described.
이종수(Jongsoo Lee),이종우(Jongwoo Lee) 대한전기학회 2015 전기학회논문지 Vol.64 No.8
I In power transmission systems, voltage changes continuously as reactive power is whether over supply or shortage. Reactive power produces in generators and consumes in transmission lines, and loads. Voltages at end points of transmission lines rise which is called Ferranti effect. Excessive voltage rising can reduce transmission equipment life, the voltage rising is usually permitted within the limit of 10%~30% excess. Shunt reactors are installed in transmission lines to put a curb on voltage rising. In this paper, we tried to do modelling for shunt reactor configuration types which are no grounding, grounded and grouded neutral reactor. Simulation are carried out for reactor magnitude for compensating transmission line capacitance.
Lee, Chong-Sun,Jang, Jong-Yun,Suh, Chang-Min The Korean Society of Mechanical Engineers 2001 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.15 No.7
The present study investigated design parameters of shunt valves and anti-siphon device used to treat patients with hydrocephalus. The shunt valve controls drainage of cerebrospinal fluid (CSF) through passive deflection of a thin and small diaphragm. The anti-siphon device(ASD) is optionally connected to the valve to prevent overdrainage when the patients are in the standing position. The major design parameters influencing pressure-flow characteristics of the shunt valve were analyzed using ANSYS structural program. Experiments were performed on the commercially available valves and showed good agreements with the computer simulation. The results of the study indicated that predeflection of the shunt valve diaphragm is an important design parameter to determine the opening pressure of the valve. The predeflection was found to depend on the diaphragm tip height and could be adjusted by the diaphragm thickness and its elastic modulus. The major design parameters of the ASD were found to be the clearance (gap height) between the thin diaphragm and the flow orifice. Besides the gap height, the opening pressure of the ASD could be adjusted by the diaphragm thickness, its elastic modulus, area ratio of the diaphragm to the flow orifice. Based on the numerical simulation which considered the increased subcutaneous pressure introduced by the tissue capsule pressure on the implanted shunt valve system, optimum design parameters were proposed for the ASD.
켈빈 소스를 포함하는 SiC MOSFET의 가전용 전력변환시스템 적용을 위한 부트스트랩 회로 설계
함지선,최성휘 전력전자학회 2024 전력전자학회 논문지 Vol.29 No.2
Research on wide bandgap(WBG) devices, such as silicon carbide metal oxide semiconductor field effect transistor(SiC MOSFET) and gallium nitride high-electron mobility transistor, has been recently conducted. The use of WBG devices in power conversion systems for home appliances has been increasingly reconsidered. Most home appliance systems use bootstrap circuits and shunt resistors to reduce costs. The bootstrap circuit with shunt resistors cannot be applied to a SiC MOSFET driving circuit in which a Kelvin source exists. In this paper, a bootstrap circuit design method for SiC MOSFET driving in the presence of shunt resistors and Kelvin sources was proposed. The validity of the proposed method was verified by a 7 kW grid-connected converter.
Bluetooth Low-Energy Current Sensor Compensated Using Piecewise Linear Model
( Jung-won Shin ) 한국센서학회 2020 센서학회지 Vol.29 No.5
Current sensors that use a Hall element and Hall IC to measure the magnetic fields generated in steel silicon core gaps do not distinguish between direct and alternating currents. Thus, they are primarily used to measure direct current (DC) in industrial equipment. Although such sensors can measure the DC when installed in expensive equipment, ascertaining problems becomes difficult if the equipment is set up in an unexposed space. The control box is only opened during scheduled maintenance or when anomalies occur. Therefore, in this paper, a method is proposed for facilitating the safety management and maintenance of equipment when necessary, instead of waiting for anomalies or scheduled maintenance. A Bluetooth 4.0 low-energy current-sensor system based on near-field communication is used, which compensates for the nonlinearity of the current-sensor output signal using a piecewise linear model. The sensor is controlled using its generic attribute profile. Sensor nodes and cell phones used to check the signals obtained from the sensor at 50-A input currents showed an accuracy of ±1%, exhibiting linearity in all communications within the range of 0 to 50 A, with a stable output voltage for each communication segment.
Upward Migration of a Peritoneal Catheter Following Ventriculoperitoneal Shunt
Cho, Kyung Rae,Yeon, Je Young,Shin, Hyung Jin The Korean Neurosurgical Society 2013 Journal of Korean neurosurgical society Vol.53 No.6
We present an unusual case of peritoneal catheter migration following a ventriculoperitoneal shunt operation. A 7-month-old infant, who had suffered from intraventricular hemorrhage at birth, was shunted for progressive hydrocephalus. The peritoneal catheter, connected to an 'ultra small, low pressure valve system' (Strata$^{(R)}$; PS Medical,Gola, CA, USA) at the subgaleal space, was placed into the peritoneal cavity about 30 cm in length. The patient returned to our hospital due to scalp swelling 21 days after the surgery. Simple X-ray images revealed total upward migration and coiling of the peritoneal catheter around the valve. Possible mechanisms leading to proximal upward migration of a peritoneal catheter are discussed.
S. Demirezen,S. Altındal,I. Uslu 한국물리학회 2013 Current Applied Physics Vol.13 No.1
The forward and reverse bias currentevoltage (IeV), capacitance/conductanceevoltage (C/GeV) characteristics of the fabricated Au/PVA (Bi-doped)/n-Si photodiode have been investigated both in dark and under 250 W illumination intensity at room temperature. The energy density distribution profile of Nss was extracted from the forward bias IeV measurements by taking the voltage dependence of effective barrier height (Fe) and Rs for photodiode both in dark and under 250 W illumination cases. The exponential growth of the Nss from midgap toward the bottom of the conductance band is very apparent for two cases. The obtained high value of n and Rs were attributed to the particular distribution of Nss at metal/PVA interface, surface and fabrication processes, barrier inhomogeneity of interfacial polymer layer and the form of barrier height at M/S interface. While the values of C and G/w increase Rs and Rsh decrease under illumination, due to the illumination induced electronehole pairs in depletion region. The voltage dependent Nss profile was also obtained from the dark and illumination capacitance at 1 MHz and these values of Nss are in good agreement. In addition, the fill factor (FF) under 250 W illumination level was found as 28.5% and this value of FF may be accepted sufficiently high. Thus, the fabricated Au/ PVA (Bi-doped)/n-Si structures are more sensitive to light, proposing them as a good candidate as a photodiode or capacitance sensor for optoelectronic applications in modern electronic industry.