• International Journal of Internet, Broadcasting and Communication
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• 제10권2호
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• pp.7-12
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• 2018

The spread of IoT (Internet of Things) technology that connects objects based on wired / wireless networks is accelerating, and IoT-based smart home technology that constitutes a super connected network connecting sensors and home appliances existing inside and outside the home is getting popular. In addition, demand for alternative energy technologies such as photovoltaic power generation is rapidly increasing due to rapid increase of consumption of energy resources. Recently, small solar power systems for general households as well as large solar power systems for installation in large buildings are being introduced, but they are effectively implemented due to limitations of small solar panels and lack of power management technology. In this paper, we have studied smart home structure and IoT / IoL device discovery algorithm for energy harvesting system based on photovoltaic power generation, It is possible to construct an efficient smart home system for device control.

• 한국통신학회논문지
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• 제42권1호
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• pp.149-152
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• 2017

본 논문에서는 에너지 하베스팅 (Energy Harvesting) 기술을 적용한 BLE (Bluetooth Low Energy) 비콘에서 전력 관리를 위한 PMIC (Power Management IC)의 출력 전압을 일정하게 유지하기 위한 방안을 연구하였다. 에너지 하베스팅 장치에서 제공되는 에너지를 확보하고 저장하기 위한 축전 장치로 캐패시터를 사용하였고, 주어진 Advertising Interval에서 BLE 모듈에 일정한 전압을 제공하기 위한 최적의 캐패시턴스를 분석하였다.

• Design & Manufacturing
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• 제16권4호
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• pp.52-59
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• 2022

Currently, Korea is an aging society and is expected to become a super-aged society in about four years. X-ray devices are widely used for early diagnosis in hospitals, and many X-ray technologies are being developed. The development of X-ray device technology is important, but it is also important to increase the reliability of the device through accurate data management. Sensor nodes such as temperature, voltage, and current of the diagnosis device may malfunction or transmit inaccurate data due to various causes such as failure or power outage. Therefore, in this study, the temperature, tube voltage, and tube current data related to each sensor and detection circuit of the diagnostic X-ray imaging device were measured and analyzed. Based on QC data, device failure prediction and diagnosis algorithms were designed and performed. The fault diagnosis algorithm can configure a simulator capable of setting user parameter values, displaying sensor output graphs, and displaying signs of sensor abnormalities, and can check the detection results when each sensor is operating normally and when the sensor is abnormal. It is judged that efficient device management and diagnosis is possible because it monitors abnormal data values (temperature, voltage, current) in real time and automatically diagnoses failures by feeding back the abnormal values detected at each stage. Although this algorithm cannot predict all failures related to temperature, voltage, and current of diagnostic X-ray imaging devices, it can detect temperature rise, bouncing values, device physical limits, input/output values, and radiation-related anomalies. exposure. If a value exceeding the maximum variation value of each data occurs, it is judged that it will be possible to check and respond in preparation for device failure. If a device's sensor fails, unexpected accidents may occur, increasing costs and risks, and regular maintenance cannot cope with all errors or failures. Therefore, since real-time maintenance through continuous data monitoring is possible, reliability improvement, maintenance cost reduction, and efficient management of equipment are expected to be possible.

• 한국멀티미디어학회논문지
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• 제17권5호
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• pp.573-581
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• 2014

The salient features of UWB(Ultra WideBand) networks such as high-rate communications, low interference with other radio systems, and low power consumption bring many benefits to users, thus enabling several new applications such as wireless universal serial bus (WUSB) for connecting personal computers (PCs) to their peripherals and the consumer-electronics (CE) in people's living rooms. Because the size of multimedia data frame, WiMedia device must transmit the fragment of MSDU. However, when the fragment of MSDU is lost, WiMedia device maintains active mode for the time to complete the transmission MSDU, and there is a problem that unnecessary power consumption occurs. Therefore we propose new power management scheme to reduce unnecessary power consumption of WiMedia devices in the case that the fragment is lost.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.149-151
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• 2005

Recently, power supply-demand instability due to the dramatic increase in power usage suchas air-conditioning load at summertime has brought forecasts of decrease in power supply capability. Therefore improving the load factor through systematic load management, in other words, Direct Load Control became necessary. Direct Load Control(DLC) system is kind of a load management program for stabilization of electric power supply-demand. It's purpose is limiting the demand of the demand side selected at peak load or other time periods. The paper presented a Design of Direct Load Controller for control the amount of power demand in demand side. The proposed Controller is cheaper and has ability of storing more power data than pre-existing device.

• 대한기계학회논문집B
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• 제30권8호
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• pp.756-763
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• 2006

PEMFC has several technical problems such as water management, long term stability and performance degradation as. PEMFC has been studied not only to solve water management, but also to generate power in stable manner to system by using a hybrid system with auxiliary energy storage device. The purpose of this study is to couple PEMFC with supercapacitor to make a hybrid system and to design and test control strategies for stable power generation in case of changing output power. The polarization curve and dynamic behaviors while changing power were investigated to find out characteristics of PEMFC stack. A DC/DC converter was fabricated in order to increase fuel cell and supercapacitor voltage and to charge supercapacitor. We found that the operation strategy 2 was recommended to the system because of solving water management problem and increasing the dynamic behavior.

• 품질경영학회지
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• 제41권4호
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• pp.659-672
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• 2013

Purpose: The purpose of this study was to estimate life time of halogen lamps and acceleration factors using accelerated life test. Methods: Voltage was selected as an accelerating variable through the technical review about failure mechanism. The test was performed at 14.5V, 15.5V and 16.5 for 4,471 hours. It was assumed that the lifetime of Halogen lamps follow Weibull distribution and the inverse power life-stress relationship models. Results: Mean lifetimes of pin and screw types were 19,477 hours and 6,056 hours, respectively. In addition, acceleration factor of two items are calculated as 4.8 and 2.2 based on 15.5V, respectively. Conclusion: The life-stress relationship, acceleration factor, and MTTF at design condition are estimated by analyzing the accelerated life test data. These results suggest that voltage was very important factor to accelerate life time in the case of halogen lamps and the life time of pin type is three times longer than screw type lamps.

• 전기학회논문지
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• 제57권5호
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• pp.741-747
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• 2008

This paper proposes a new concept of IDSP(Intelligent Digital Switchgear Panel) which can solve the problem of the safety, the reliability and the convenience to correspond to the requirement of the general electric customer or electric power company under the ubiquitous-based home automation environments. By analyzing their requirement functions, a 32-bit micro processor is adopted as main controller to support the designed functions efficiently. The DSP-based single phase power management device is utilized to collect the electric power information and the ethernet convertor to communicate through internet among the IDSPs and the remote computer system. In the proposed IDSP, the several functions are implemented such as the earth leakage level display and waveform transmission, the electric fee display, the voltage management, the load management and the load control function. Finally, the prototype of the IDSP is made experimently based on the designed results, and then the effectiveness is verified by testing its basic functions.

• 한국전자통신학회논문지
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• 제15권2호
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• pp.357-362
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• 2020

군 전술정보통신체계(TICN: Tactical Information and Communication Network)의 하위체계라 할 수 있는 전술다기능단말기(TMFT: Tactical Multi-Functional Terminal)는 개인 사용자에게 음성통화, 데이터 송수신, 멀티미디어 서비스를 제공하는 체계이다. 2011년도 개발당시 전술다기능단말기 전원회로는 충전IC를 거쳐 각각의 소자에 전원을 공급하는 구조였으나, 새로 개선된 전원회로는 충전IC를 별도로 구성하지 않고 PMIC(Power Management Integrated Circuit)를 통해 각 소자에 전원이 공급되도록 하였다. 본 논문에서는 개발단계의 전원회로설계가 적용된 전술다기능단말기와 신규 PMIC를 적용한 전술다기능단말기의 전원구조를 비교하였다. 그리고 소비전류, 충전시간, 충전 시 단말기 온도상승 등의 성능평가를 통해서 설계 개선 및 부품의 적합성을 검증하였다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2014년도 추계학술대회
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• pp.577-580
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• 2014

본 논문에서는 자동 스위칭 기능을 갖는 이중 입력 에너지 하베스팅 회로를 제안한다. 열전소자와 진동소자로부터 출력되는 에너지는 최대 가용전력지점이 개방전압의 1/2로 같기 때문에 동일한 MPPT(Maximum Power Point Tracking) 제어회로를 사용할 수 있다. 제안된 회로는 하나의 MPPT 제어회로를 사용하고, 자동 스위칭 기능을 적용하여 열전소자의 출력과 진동소자의 출력을 모니터링하여 전압이 더 큰 소자로부터 최대 가용전력을 수확한다. 수확된 에너지는 전하펌프 회로에 의해 승압된 후 저장 커패시터에 저장되고 PMU(Power Management Unit)를 통해 부하에 공급된다. 제안된 회로는 $0.35{\mu}m$ CMOS 공정으로 설계하였으며, 모의실험을 통해 동작을 검증하였다. 설계된 최초의 칩 면적은 PAD를 포함하여 $1.4mm{\times}1.2mm$이다.