• Journal of the Korean Society for Railway
• /
• v.20 no.1
• /
• pp.31-42
• /
• 2017

Many studies have been performed to reduce electric consumption in railway systems. Due to its low conduction loss and high regenerative braking efficiency characteristics, the ESS powered railway system is chosen as a promising candidate for future railway systems. This paper introduces the ESS powered railway system and analyzes current power charge calculation methods that have been set up by KEPCO (Korea Electric Power Corporation). Based on the analysis, this paper proposes two different power charge reduction methods for the railway system. One is to smooth the peaks of traction energy consumption by supplying additional energy to the grid. The other is to save electric charge by reducing electric energy consumed by the railway during the energy peak time, 2 p.m.~5 p.m., which has highest 'Won/kWh' rates. To verify the effectiveness of the proposed method, the power charge of Seoul Metro Line 2 is recalculated using the method.

• Journal of the Semiconductor & Display Technology
• /
• v.20 no.4
• /
• pp.102-107
• /
• 2021

In this paper, the measurements of received power was shown and compared in two developed 5.8GHz 25W wireless charging systems. One is the system using commercial transmission antenna, and the other is the system using transmission antenna combined with metamaterial. The system combined with metamaterial shows higher received power due to negative reflective index of metamaterial. In addition, a comparative analysis of the systems shows that the transmission efficiency in the systems can decrease the real gain of transmission antenna due to higher side robe of beam pattern. The side robe beams of transmitting antenna interferes transmitted beam with the reflected beams from the bottom region due to the side robes. The failure problems of the RF wireless charging systems are discussed and proposed in order to charge mobile devices through the RF wireless charging system.

• Transactions on Electrical and Electronic Materials
• /
• v.16 no.5
• /
• pp.241-249
• /
• 2015

Phase-locked-loops (PLL) have been employed in high-speed data transmission systems like wireless transceivers, disk read/write channels and high-speed interfaces. The majority of the researchers use a charge pump (CP) to obtain high performance from PLLs. This paper presents a review of various CMOS CP schemes that have been implemented for PLLs and the relationship between the CP parameters with PLL performance. The CP architecture is evaluated by its current matching, charge sharing, voltage output range, linearity and power consumption characteristics. This review shows that the CP has significant impact on the quality performance of CP PLLs.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2014.10a
• /
• pp.654-657
• /
• 2014

In this paper, we proposed a short distance control method of AtoN charge and discharge regulator. The proposed control measures, was constructed by applying the communication standards NEMA018 of AtoN and control function analysis of the charge and discharge regulator that has been operating in the country. By using the control method is proposed, while maintaining the waterproof without product degradation, there is an advantage that can communicate control wired or wireless. Also, it is possible to ensure the accessibility of the charge and discharge regulator in operation, it is effective for maintenance. In this paper, installed the application to control the charge and discharge regulator to the smart-phone. by using a PC and Blue-tooth communication, to examine the effectiveness of the control information. Future, control method of power controller, can provide a national standard.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.7 no.2
• /
• pp.95-101
• /
• 2012

In order to supply emotion service depending on user's emotional change in a mobile environment, various researches have been carried. This paper discusses a protocol for wireless charging and an embedded platform of the mobile emotional sensing device which supports that. Wireless charging process relieves user's vexatious task to charge the emotional sensing device. To support wireless charging, there are one basestation and several mobile devices. Basestation coordinates and controls the devices over wireless communication, as well as supplies energy. For 1:N communication we defines the network whose superframe is classified into four categories: a network join superframe, a charging request superframe, a charging superframe and an inactive superframe. Physical layer provides how to supply energy to the devices and communicate physically. Mobile device is equipped with energy charged circuits, which correspond with the defined energy supplying method, as well as bidirectional communication circuits. Mobile device monitors and analyzes its own battery status, and is able to send a request packet to basestation. Therefore, it can be charged before its battery is exhausted without user's perception.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.17 no.10
• /
• pp.2239-2244
• /
• 2013

Industrial machines have constraints on movement due to its wire for power supply. Recently, the research on wireless power supply for industrial machine which is required to move freely is receiving a lot of attention. In this paper, we suggest a magnetic induction system which can charge a equipment's battery with wireless at a close range. The system was designed to operate at 13.56 MHz and a distance of 20~30 mm between the transmitting and the receiving power module. From experiment, it was found that it takes about 135 minutes for charging the battery with about 15 V using the proposed system.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.10 no.12
• /
• pp.5307-5327
• /
• 2016

Restricted by finite battery energy, traditional wireless sensor networks (WSNs) can only maintain for a limited period of time, resulting in serious performance bottleneck in long-term deployment of WSN. Fortunately, the advancement in the wireless energy transfer technology provides a potential to free WSNs from limited energy supply and remain perpetual operational. A mobile charger called wireless charging vehicle (WCV) is employed to periodically charge each sensor node and keep its energy level above the minimum threshold. Aiming at maximizing the ratio of the WCV's vocation time over the cycle time as well as guaranteeing the perpetual operation of networks, we propose a feasible and optimal solution to this issue within the context of a real-time large-scale deployed WSN. First, we develop two different types of charging cycles: initialization cycles and renewable cycles and give relevant algorithms to construct these two cycles for each sensor node. We then formulate the optimization problem into an optimal construction algorithm and prove its correctness through theoretical analysis. Finally, we conduct extensive simulations to demonstrate the effectiveness of our proposed algorithms.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2016.05a
• /
• pp.71-72
• /
• 2016

In this paper, RTLS tag for high-precision positioning and wireless power transmission module is designed in order to solve the battery replacement problem. Wireless charging pad is available to charge the 4 RTLS tags at once. Charging time of the proposed protype in 50 cm distance is 22 minutes based on 3V reference voltage and 500 mW.

• Journal of information and communication convergence engineering
• /
• v.10 no.3
• /
• pp.220-224
• /
• 2012

We report an experimental demonstration of $4{\times}4$ multiple-input multiple-output (MIMO) wireless visible light communications (VLC) using a charge-coupled device image sensor receiver instead of a photodiode receiver. An image sensor is a kind of digital camera, which is used in most mobile devices such as smart phones or laptop computers and a promising commercial candidate for a VLC receiver. The transmission distance of the experimental result is over 10 m, enough for most indoor communication applications. We expect that the MIMO VLC technique based on image sensor receivers can be widely used with the development of high-speed image sensors.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2010.05a
• /
• pp.845-848
• /
• 2010

After analyzing various information gathered in Wireless Sensor Networks, it is sent to the node far from it. If it fails to keep its minimum power considering power consumption, the node and the network wouldn't work. There are many research that each node gets the power from solar cells and keep the life to maximize networks'life thus solar cells should be modeled considering power consumption. This thesis propose the fit model of solar cells considering charge and discharge in Wireless Sensor Networks.