• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.3
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• pp.1674-1688
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• 2019

As environmental pollution and fossil fuel energy problems from fuel vehicle have occurred, the interest of electric vehicle(EV) has increased. EV industry and energy industry have grown dynamically in these days. It is expected that the next generation of primary transportation will be EV, and it is necessary to prepare EV infra and efficient energy management such as EV communication protocol, EV charge station, and smart grid. Those EV and energy industry fields are now on growth. Also, the study and development of them are now in progress. In this paper, distributed charge signal processing software for smart slow and quick EV charge is proposed and designed for dealing with EV charge demand. The software consists of smart slow and quick EV charge schedule engine and EV charge power distribution core. The software is designed to support two charge station types. One is normal EV charge station and the other is bus garage EV charge station. Both two types collect the data from EV charge stations, and then analyze the collected data. The software suggests optimized EV charge schedule and deliveries EV charge power distribution information to power switchboard system, and the designed software is implemented on embedded system. It is expected that the software provides efficient EV charge schedule.

• Journal of Electrical Engineering and Technology
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• v.7 no.6
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• pp.824-833
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• 2012

In this paper, a coordinated state-of-charge (SOC) control strategy for the energy storage system (ESS) operating under microgrid islanded mode to stabilize the frequency and voltage was proposed. The proposed SOC control loop is made up of PI controller, which uses a SOC state of the energy storage system as an input and an auxiliary reference value of secondary control as an output. The SOC controller changes the auxiliary reference value of secondary control to charge or discharge the ESS. To verify the proposed control strategy, PSCAD/EMTDC simulation study was performed. The simulation results show that the SOC of the ESS can be regulated at the desired operating range without degrading the stabilizing control performance by proposed coordinated SOC control method.

• 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.

• Journal of Electrical Engineering and Technology
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• v.12 no.4
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• pp.1369-1375
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• 2017

This paper presents an optimal operation scheduling algorithm for a smart home with energy storage system, electric vehicle and distributed generation. The proposed algorithm provides the optimal charge and discharge schedule of the EV and the ESS. In minimizing the electricity costs of the smart home, it considers not only the cost of energy purchase from the grid but also the life cost of batteries. The life costs of batteries are calculated based on the relation between the depth of discharge and life time of battery. As the life time of battery depends on the charge and discharge pattern, optimal charge and discharge schedule should consider the life cost of batteries especially when there is more than one battery with different technical characteristics. The proposed algorithm can also be used for optimal selection of size and type of battery for a smart home.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.838-843
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• 2008

Cause of struggling to escape from dependency of fossil fuels, the fuel cell and the Plug-in Hybrid Electric Vehicle (PHEV) draw attention in the all of the world. Especially, the Polymer Electrolyte Membrane Fuel Cell (PEMFC) systems have been anticipated for next generation's energy supplying system, and we can predict the PHEV will enlarge the market share in the next few years to reduce not only the air pollution in the metropolis but the fuel-expenses of commuters. This paper presents simulation results about the strategy of smart charging system for PHEV in the residential house which has 1 kW PEMFC cogeneration system. The smart charging system has a function of recommending the best time to charge the battery of PHEV by the lowest energy cost. The simulated energy cost for charging the battery based on the electricity demand data pattern in the house. The house which floor area is $132\;m^2$ (40 pyeong.). In these conditions, the annual gasoline, electricity, and total energy cost to fuel the PHEV versus Conventional Vehicle (CV) have been simulated in terms of cars' average life span in Korea.

• Smart Media Journal
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• v.9 no.1
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• pp.84-91
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• 2020

Along with increasing the renewable energy utilization, many researches have paid attention on the utilization and efficiency of energy storage systems. Especially, it is required an operational model in order to actively respond with each system's failure of sub-systems in the solar energy storage system. This paper proposes an energy management scheme by estimating the newly generated power based on the solar power generation samples. With comparing the estimated battery charging power in real time and the total charging power of the battery rack, a charge model is applied to adjust the charging power, As a result, the stability of energy storage system would be improved by suppressing the battery heat while maintaining battery C-Rate.

• Journal of Information Processing Systems
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• v.13 no.6
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• pp.1487-1495
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• 2017

With increasing interests in renewables, more consumers are installing an energy storage system (ESS) in their backyards, and thus, the ESS will play a critical role in the emerging smart grid. Due to mechanical properties, however its operational dynamics must be well understood before connecting the ESS to the smart grid (and eventually to an IT system). To this end, we investigate charging and discharging processes in detail. This paper, then, proposes methods for four type tests (state of charge test, conversion efficiency test, response time test, and ramp rate test) that can assess the dynamics of the ESS. The proposed methods can capture accurate delay values of mechanical processes in the ESS, and it is expected for those values to help design real-time communication systems in the smart grid involving the ESS.

• 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.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.10
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• pp.1499-1504
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• 2013

As oil price and demand for environment friendly vehicle rapidly increase, research on electric car is being widely carried out. Especially, NEV(Neighborhood Electric Vehicle) is a pollution-free vehicle that can be mass-produced which the time of development for related technologies is urgently needed. In this paper the On-Board charger for mid- and large- sized secondary cell is applicable in aerospace and other general industries, and the Off-Board standing charger is expected to be employed in creating charging infrastructure.

• Journal of Electrical Engineering and Technology
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• v.12 no.5
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• pp.1789-1797
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• 2017

It is necessary to charge electric vehicles in order to drive them. Thus, it is essential to have electric vehicle charging facilities in place. In the case of a household battery charger, the power similar to that consumed by a household with a basic contract power of 3kW is consumed. In addition, many consumers who own an electric vehicle will charge their vehicles at the same time. The simultaneous charging of electric vehicles will cause the load to increase, which then will lead to the imbalance of supply and demand in the distribution system. Thus, a smart charging scheme for electric vehicles is an essential element. In this paper, simulated conditions were set up using real data relating to Korea in order to design a smart charging technique suitable for the actual situation. The simulated conditions were used to present a smart charging technique for electric vehicles that disperses electric vehicles being charged simultaneously. The EVs and Smart Charging Technique are modeled using the Electro Magnetic Transients Program (EMTP).