• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.4
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• pp.273-279
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• 1998

In this paper, the proposed charging system consists of step charging mode and time-sharing equalization charging mode. As $\Delta$V=O point is detected, the proposed cut-off method will selectively cut off the only battery to reach the $\Delta$V=O point, preventing serial-connected batteries from undercharging. In the start of each step, the equalization charging mode is performed to reduce the capacity difference among the batteries. Though it is added to simple circuit for selective cut-off, comparing with recently used step-charging method, this system can improve the life cycle of battery and charging efficiency, and be also very effective for preventing the batteries from overcharging and undercharging.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.4
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• pp.395-402
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• 2016

When the operation of battery is converted at charging and discharging system based on a DC micro grid, the voltage is fluctuated. And excessive voltage fluctuation could cause damage or failure of charging and discharging equipment. Therefore, in this paper, we studied the operating schedule of the charging and discharging system based on the DC micro grid and a design point of the capacitor which was able to reduce the voltage fluctuation. A result of computer simulation showed that when a fluctuation-reducing capacitor which had an initial value of 600V/35mF was applied at the charging and discharging system based on a DC micro grid which was operated with three charging battery sets and five discharging battery sets, voltage fluctuation by charging and discharging operation was reduced by about 63.3%. Furthermore, voltage fluctuation which occurred when initial network voltage was stabilized was reduced by about 73%.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.3
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• pp.541-548
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• 2012

On this paper, we proposed a design rule of charger monitoring system which allow us to watch the charging status and verify it for building the electric chargers infrastructure by spread of electric vehicle. Gathering the charging status of battery by proposed system makes us to enhance the charging algorithm, to interface with BMS(Battery Management System) of electric vehicle, to control the charging process with users. Because the technology of rapid charging is dependant upon various factors such as a performance and stability of battery. We proposed the monitoring system of rapid charger based on CAN protocol that can watch a working status of rapid charger including the charging status of battery with real time and can reduce the charging time of battery with optimized status. We also implement it and evaluate its performance.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.8
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• pp.1523-1528
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• 2011

This paper proposes buck-type charging method using motor inductance, 3-phase inverter and bi-directional converter without an additional charger in plug-in hybrid electric vehicles. The proposed system has advantages over the conventional system such as high charging efficiency, high power factor, and low total harmonic distortion. The validity of each methods are verified by theoretical analysis and simulation.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.482-483
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• 2014

In this paper, an electric yard tractor (YT) with furtive charging system is investigated. YT is one of pollution sources in container terminals. The furtive charging system does not impose difficulties on YT day-schedule because charging is performed when a YT is waiting under RTGC (Rubber Type Gantry crane) or Quay-wall crane.

• International Journal of Internet, Broadcasting and Communication
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• v.9 no.2
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• pp.1-10
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• 2017

The high costs of electric vehicle supply equipment (EVSE) and installation are currently a stumbling block to the proliferation of electric vehicles (EVs). The cost-effective solutions are needed to support the expansion of charging infrastructure. In this paper, we develope EV charging system based on the big data analysis of the power consumption patterns. The developed EV charging system is consisted of the smart EV outlet, gateways, powergates, the big data management system, and mobile applications. The smart EV outlet is designed to low costs of equipment and installation by replacing the existing 220V outlet. We can connect the smart EV outlet to household appliances. Z-wave technology is used in the smart EV outlet to provide the EV power usage to users using Apps. The smart EV outlet provides 220V EV charging and therefore, we can restore vehicle driving range during overnight and work hours.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.652-654
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• 2015

Integrated switched reluctance motor drive as an electric vehicle battery charger is presented in this paper. The SRM, which is used as the traction power in the driving mode, is used in the charge circuit to improve the power factor of charging system. The charging circuit can share the power switches of the asymmetric converter and phase windings of SRM to charge the battery, and can reduce the size and cost of the system in the plug-in system. To keep the rotor at standstill, zero torque control method is proposed. Since the inductances of the SRM windings are not same at any stop position, the charger controller controls the reference current to satisfy the total charging current with PFC and zero torque condition. A novel cubic equation method is proposed as a current reference distributor of the charging controller. Simulations are performed by MATLAB software and results satisfy the Effectiveness of proposed battery charging system.

• Journal of Electrical Engineering and Technology
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• v.11 no.4
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• pp.810-819
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• 2016

Uncoordinated charging of large-scale electric vehicles (EVs) will have a negative impact on the secure and economic operation of the power system, especially at the distribution level. Given that the charging load of EVs can be controlled to some extent, research on the optimal charging control of EVs has been extensively carried out. In this paper, two possible smart charging scenarios in China are studied: centralized optimal charging operated by an aggregator and decentralized optimal charging managed by individual users. Under the assumption that the aggregators and individual users only concern the economic benefits, new load peaks will arise under time of use (TOU) pricing which is extensively employed in China. To solve this problem, a simple incentive mechanism is proposed for centralized optimal charging while a rolling-update pricing scheme is devised for decentralized optimal charging. The original optimal charging models are modified to account for the developed schemes. Simulated tests corroborate the efficacy of optimal scheduling for charging EVs in various scenarios.

• Journal of Power System Engineering
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• v.19 no.5
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• pp.73-79
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• 2015

The effects of hydrogen charging on the mechanical properties of 304 stainless steels were investigated in conjunction with the detailed examinations of their fracture modes. The dependence of the absorbed impact energy and the surface hardness of the 304 stainless steels on the hydrogen charging time was characterized. The tensile properties of the 304 stainless steels by the variation of cross-head speed were also evaluated at the room temperature. The hydrogen charging was performed by an electrolysis method for all specimens of the 304 stainless steels. The mechanical properties of the 304 stainless steels exhibited the sensitivity of embrittlement due to a hydrogen charging. The correlation between mechanical properties and fracture surfaces was discussed.

• Journal of Ocean Engineering and Technology
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• v.35 no.4
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• pp.305-312
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• 2021

There is a gradual increase in the need for energy charging in marine environments because of energy limitations experienced by electric ships and marine robots. Buoys are considered potential energy charging systems, but there are several challenges, which include the need to maintain a fixed position and avoid hazards, dock with ships and robots in order to charge them, be robust to actions by birds, ships, and robots. To solve these problems, this study proposes a smart buoy robot that has multiple thrusters, multiple docking and charging parts, a bird spike, a radar reflector, a light, a camera, and an anchor, and its mechanism is developed. To verify the performance of the smart buoy robot, the position control under disturbance due to wave currents and functional tests such as docking, charging, lighting, and anchoring are performed. Experimental results show that the smart buoy robot can operate under disturbances and is functionally effective. Therefore, the smart buoy robot is suitable as an energy charging system and has potential in realistic applications.