• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.323-324
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• 2013

This paper presents a simple and cost-effective stand-alone rapid battery charging system of 30kW for electric vehicles. The proposed system mainly consists of active front-end rectifier of neutral point clamped 3-level type and non-isolated bi-directional dc-dc converter of multi-phase interleaved half-bridge topology. The charging system is designed to operate for both lithium-polymer and lithium-ion batteries. The complete charging sequence is made up of three sub-interval operating modes; pre-charge mode, constant-current mode, and constant-voltage mode. The pre-charge mode employs the stair-case shaped current profile to accomplish shorter charging time while maintaining the reliable operation of the battery. The proposed system is specified to reach the full-charge state within less than 16min for the battery capacity of 8kWh by supplying the charging current of 78A. Owing to the simple and compact power conversion scheme, the proposed solution has superior module-friendly mechanical structure which is absolutely required to realize flexible power expansion capability in a very high-current rapid charging system.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.349-352
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• 2008

The most concerning issue in these days is the energy crisis by increasing threat of global warming and depletion of natural resources. In the situations, the Plug-in Hybrid Electric Vehicle (PHEV) is drawing attention from many countries for the next generation's car which has higher fuel efficiency and lower environmental impact. This paper presents simulation results about the limit capacity of central power-grid which doesn't have enough surplus electric power for charging PHEVs. Therefore, this paper also presents a smart charging system that can charge the PHEVs with a function of distributing demands of charging. The smart charging system is an agent facility between the government and consumer, which can recommend the best time to charge the battery of PHEVs by the lowest energy cost. This function of choosing time-slots is the technical system for the government which wants to control the consumption rate of electric power for PHEVs. Finally, this paper presents the economic feasibility of PHEVs from the two kinds of price system, midnight electric price and home electric price.

• The Transactions of the Korean Institute of Power Electronics
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• v.17 no.2
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• pp.99-106
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• 2012

In this paper, 15[kW] AC regenerative system for battery charging and discharging test is proposed. The regenerative system is able to regenerate surplus energy to the grid in discharging mode, and the inverter of the system can be operated as a converter to compensate scarce energy in charging mode. In case of the conventional DC charging and discharging system, the regenerative energy is consumed by a resistor. However, as the proposed system regenerates the surplus energy to the grid through using DC-AC inverter, the energy saving effect can be achieved. In this paper, 15[kW] battery charging and discharging system is developed, and the validity of the system is verified through simulation and experimental results.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.6
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• pp.804-808
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• 2018

Interest in wireless power transfer (WPT) has been growing recently due to the rapid increase in the use of electronic devices. Wireless charging systems are currently being applied to mobile phones and many studies are being conducted to apply wireless charging systems to various devices. The current wireless charging systems are capable of 1:1 charging. For wireless charging, when the devices with the same resonance frequency are present in the vicinity, the charging efficiency may be significantly lowered due to frequency interference or the wireless charging systems may stop operating. In this paper, variable capacitors were applied to a superconducting WPT system to solve the frequency interference among multiple devices with the same frequency. When a wireless charging system was performing 1:1 operation, the frequency of the other devices was varied using variable capacitors. As a result, it was confirmed that the highly efficient WPT is possible without frequency interference even when multiple receivers are present.

• KEPCO Journal on Electric Power and Energy
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• v.6 no.3
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• pp.315-319
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• 2020

The modern transportation and mobility sector is expected to encounter high penetration of Electric Vehicles (EVs) because EVs contribute to reducing the harmful emissions from fossil fuel-powered vehicles. With the prospective growth of EVs, sufficient and convenient facilities for fast charging are crucial toward satisfying the EVs' quick charging demand during their trip. Therefore, the Fast Electric Vehicle Charging Stations (FECS) will be a similar role to gas stations. In this paper, we study a charging scheduling problem for the FECS with solar photovoltaic (PV) and an Energy Storage System (ESS). We formulate an optimization problem that minimizes the operational costs of FECS. There are two cost and one revenue terms that are buying cost from main grid power, ESS degradation cost, and revenue from the charging fee of the EVs. Simulation results show that the proposed scheduling algorithm reduces the daily operational cost by effectively using solar PV and ESS.

• Journal of IKEEE
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• v.22 no.2
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• pp.455-459
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• 2018

In this paper, proposed a multi-channel charging control strategy for electric vehicle. This control strategy can adjust the charging power according to the calculated state-of-charge (SOC). Electric vehicle (EV) charging system using Particle Swarm Optimization (PSO) algorithm is proposed. A stochastic optimization algorithm technique such as PSO in the time-of-use (TOU) price used for the energy cost minimization. Simulation results show that the energy cost can be reduced using proposed method.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.1
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• pp.124-130
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• 2011

In this paper, We design and implementation of Self-Charging Module for charging to battery which obtaining the environment inergy such as solar energy. The power chared battery through the charging module send to sensor node. And implementation of System Activation Module(SAM) based on ID system and Dynamic Power Management Module(DPM) with SPO(Self Power Off). This system consume power only communication between the sensor nodes. We verification this system by implementing the high efficiency poweer management system.

• Journal of information and communication convergence engineering
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• v.18 no.3
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• pp.147-154
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• 2020

In this study, we created a system that can determine the number of vehicles entering and departing a charging station in real time for solving waiting time problems during refueling. Accordingly, we use the You Only Look Once object detection algorithm to detect and count the number of vehicles in the charging station and send the data to the Firebase Realtime Database. The result is shown using an Android application that provides a map function with the Kakao Maps API at the user interface side. Our system has an accuracy of 91% and an average response time of 3.1 s. Therefore, this system can be used by drivers to determine the availability of a charging station and to identify the charging station with the least waiting time for charging their vehicle.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.11
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• pp.628-634
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• 2002

A capacitor-charging power supply using high frequency inverter technology is strongly recommended for the charging section of the pulsed power supplies. A high frequency inverter swiching makes the overall system size small. The command-charging feature can guarantee the higher reliability of switching function. The protection circuit can be easily included in the system and the good regulation of charging voltage can be acieved by the feedback system. Several modules can be stacked to supply required output power and a failed module can be easily replaced. A 50-kV, 35-kW capacitor charging power supply is developed. In this paper the detailed design and test results of a prototype unit are presented.

• Journal of Electrical Engineering and Technology
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• v.7 no.5
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• pp.736-744
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• 2012

In this paper, a battery charging system for Plug-in Hybrid Electric Vehicle (PHEV) and Electric Vehicle (EV), and operation algorithm of charging system are introduced. Also, the proposed charging system uses commercial electricity in order to charge the battery of parked PHEV and 48V battery charging system with power factor controllable single phase converter for PHEV is investigated in this paper. This research verifies the power factor control of input and the converter output controlled by the charge control algorithm through simulation and experiment.