• 한국위성정보통신학회논문지
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• 제6권2호
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• pp.131-135
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• 2011

본 논문에서는 에너지 센서 네트워크 적용을 위한 AC 전력센싱 기능과 지능형 대기전력 차단제어 기능을 가진 무선 스마트 플러그 설계와 적응식 대기전력 차단제어 알고리즘을 제안하고 구현하였다. 적응식 대기전력 차단제어 알고리즘은 사무기기나 가전기기마다 상이한 대기전력 문턱치를 학습기능에 의해 자동 감지하고, 적응 설정되게 함으로서 사용자의 편이성과 신뢰성 높은 대기전력 차단제어 기능을 제공하여 에너지소비 절감 효과를 극대화 할 수 있도록 하였다. 구현된 시제품의 기능을 검증한 결과, 설계 요구기능을 모두 만족하였으며 대기전력 소비를 절감할 수 있는 지능형 전력센서로서 실용성이 있음을 확인하였다.

• 한국전자통신학회논문지
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• 제16권4호
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• pp.605-610
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• 2021

현재까지 알려진 무선충전 방식 중에서 장거리에서 가장 효율이 좋은 방식은 레이저를 이용한 방식이다. 여기에 레이저를 이용한 무선통신 기술을 결합한다면 다양한 분야에 활용이 가능할 것이다. 이에 본 논문에서는 레이저를 이용한 무선충전 및 무선통신의 동시전송 기술에 관하여 연구하고 이에 대한 실험 결과를 보인다. 이 기술은 광 무선충전을 위해서 송신부에 전/광 변환을 위한 레이저 광원을 사용하고 수신부에는 광/전 변환을 위한 태양전지를 사용한다. 또한, 광 무선통신을 위해 해당 레이저 광신호에 반송파를 이용하여 신호를 송신하는 방식이다. 본 논문에서는 실험을 통해 100 mW 레이저 송신부와 태양전지 수신부를 이용하여 광 무선충전은 1.9 %의 DC-to-DC 효율을 보였으며, 무선 광통신은 전송거리가 15 m일때 최대 90 kbps의 전송속도를 보였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 제13회 신호처리 합동 학술대회 논문집
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• pp.533-536
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• 2000

We consider the design of quadrature amplitude modulation (QAM) transceivers f3r fixed wireless communications. The use of adaptive power control in the transmitter (Tx) can provide BER performance robust to fading and improved BER performance. The BER performance is evaluated by analytical and simulation results when multi-level QAM transceiver employing power control in the Tx is applied to fixed wireless channel with flat fading and frequency selective fading. The effect of power control parameters such as power control range and power control step size is investigated

• 디지털산업정보학회논문지
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• 제16권2호
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• pp.61-68
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• 2020

Nuclear power plants have a lower cost of power generation, and they are more eco-friendly than other power generation plants. Also, we need to prepare nuclear plant accidents because of their severe damage. In the event of a safety accident, such as a radiation leak, by applying a wireless sensor network to a nuclear power plant, many sensor nodes can be used to monitor radiation and transmit information to an external base station to appropriately respond to the accident. However, applying a wireless sensor network to nuclear power plants requires routing protocols that consider the sensor network size and bypass obstacles such as plant buildings. In general, the hierarchical-based routing protocols are efficient in energy consumption. In this study, we look into the problems that may occur if hierarchical-based routing protocols are applied to nuclear power plants and propose improved routing protocols to solve these problems. Simulation results show that the proposed routing protocol is more effective in energy consumption than the existing LEACH protocol.

• 한국초전도ㆍ저온공학회논문지
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• 제18권1호
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• pp.41-45
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• 2016

The technology of supplying the electric power by wireless power transfer (WPT) is expected for the next generation power feeding system since it can supply the power to portable devices without any connectors through large air gap. As such a technology based on strongly coupled electromagnetic resonators is possible to deliver the large power and recharge them seamlessly; it has been considered as a noble option to wireless power charging system in the various power applications. Recently, various HTS wires have now been manufactured for demonstrations of transmission cables, motors, MAGLEV, and other electrical power components. However, since the HTS magnets have a lower index n value intrinsically, they are required to be charged from external power system through leads or internal power system. The portable area is limited as well as the cryogen system is bulkier. Thus, we proposed a novel design of wireless power charging system for superconducting HTS magnet (WPC4SM) based on resonance coupling method. As the novel system makes possible a wireless power charging using copper resonance coupled coils, it enables to portable charging conveniently in the superconducting applications. This paper presented the conceptual design and operating characteristics of WPC4SM using different shapes' copper resonance coil. The proposed system consists of four components; RF generator of 370 kHz, copper resonance coupling coils, impedance matching (IM) subsystem and HTS magnet including rectifier system.

• Journal of Power Electronics
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• 제18권1호
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• pp.300-308
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• 2018

An online estimation method for wireless power transfer (WPT) systems is presented without using any measurement of the secondary side or the load. This parameter estimation method can be applied with a controlling strategy that removes both the receiving terminal controller and the wireless communication. This improves the reliability of the system while reducing its costs and size. In a wireless power transfer system with an LCCL impedance matching circuit under a rectifier load, the actual load value, voltage/current and mutual inductance can be reflected through reflected impedance measuring at the primary side. The proposed method can calculate the phase angle tangent value of the secondary loop circuit impedance via the reflected impedance, which is unrelated to the mutual inductance. Then the load value can be determined based on the relationships between the load value and the secondary loop impedance. After that, the mutual inductance and transfer efficiency can be computed. According to the primary side voltage and current, the load voltage and current can also be detected in real-time. Experiments have verified that high estimation accuracy can be achieved with the proposed method. A single-controller based on the proposed parameter estimation method is established to achieve constant current control over a WPT system.

• 전기전자학회논문지
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• 제22권1호
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• pp.216-222
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• 2018

장거리 무선전력전송 기술은 단순한 핸드폰 및 소형가전을 넘어서, 4차 산업혁명의 핵심기술로 자리 잡은 드론, 로봇, 전기자동차, IoT 센서 네트워크 등에 폭넓게 적용될 수 있다. 본 논문에서는 이미 기술적으로 보편화된 기존의 근거리 무선전력전송 기술을 벗어나, 급속한 기술발전으로 통하여 상용화 단계에 이른 장거리 무선전력전송 기술의 발전방향을 살펴보고자 한다. 이를 통하여, 핵심기술을 파악과 기술적인 극복과제를 도출함으로써 국내의 연구수준과 나아갈 바를 점검하고자 한다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 추계학술대회 논문집
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• pp.25-26
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• 2012

Wireless power transmission introduced by Tesla has instrumented by many scientists of the world. This technique first was utilized as wireless communications such as radio in long range transmission. And contactless transmission using inductive property was used on white goods. In 2007, MIT' lab introduced that new wireless power transmission by magnetic resonance which has about 50% efficiency and 2M transmission distances, it was a chance to refocus a new possibility of wireless power transmission. In this paper, using LC coupling compensate the short distances of contactless transmission, this simple method could transmit about 30cm distances. Using this approach, it can be solved the short transmission distances, a drawback of Electromagnetic inductive coupling method.

• Journal of electromagnetic engineering and science
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• 제15권2호
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• pp.104-110
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• 2015

As civil infrastructures continue to deteriorate, the demand for structural health monitoring (SHM) has increased. Despite its outstanding capability for damage identification, many conventional SHM techniques are restricted to huge structures because of their wired system for data and power transmission. Although wireless data transmission using radio-frequency techniques has emerged vis-$\grave{a}$-vis wireless sensors in SHM, the power supply issue is still unsolved. Normal batteries cannot support civil infrastructure for no longer than a few decades. In this study, we develop a magnetic resonance-based wireless power transmission system, and its performance is validated in three different mediums: air, unreinforced concrete, and reinforced concrete. The effect of concrete and steel rebars is analyzed.

• ETRI Journal
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• 제33권2호
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• pp.279-282
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• 2011

Coexistence analysis is extremely important in examining the possibility for spectrum sharing between orthogonal frequency-division multiplexing (OFDM)-based international mobile telecommunications (IMT)-Advanced and other wireless services. In this letter, a new closed form method is derived based on power spectral density analysis in order to analyze the coexistence of OFDM-based IMT-Advanced systems and broadcasting frequency modulation (FM) systems. The proposed method evaluates more exact interference power of IMT-Advanced systems in FM broadcasting systems than the advanced minimum coupling loss (A-MCL) method. Numerical results show that the interference power is 1.3 dB and 3 dB less than that obtained using the A-MCL method at cochannel and adjacent channel, respectively. This reduces the minimum separation distance between the two systems, which eventually saves spectrum resources.