• Journal of Power Electronics
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• v.16 no.1
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• pp.268-276
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• 2016

A hybrid sinusoidal-pulse current (HSPC) charging method for the Li-ion batteries in electric vehicle applications is proposed in this paper. The HSPC charging method is based on the Li-ion battery ac-impedance spectrum analysis, while taking into account the high power requirement and system integration. The proposed HSPC method overcomes the power limitation in the sinusoidal ripple current (SRC) charging method. The charger shares the power devices in the motor inverter for hardware cost saving. Phase shifting in multiple pulse currents is employed to generate a high frequency multilevel charging current. Simulation and experimental results show that the proposed HSPC method improves the charger efficiency related to the hardware and the battery energy transfer efficiency.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1-2
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• 2015

In this paper, a 2-phase feeder system for wireless vehicle charging is investigated, which generates moving magnetic field with nearly constant magnitude using 2-phase currents. A moving field is very useful to magnetizing pickups mounted on underneath of electric vehicles.

• 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.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.12
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• pp.1015-1020
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• 2016

An advantage of electric vehicles is that they are environmentally sustainable because they do not emit exhaust gases, such as $CO_2$ or Nox. A disadvantage is the low power performance of the motor and battery source, necessitating a reduction in the weight of the vehicle to increase efficiency. Another disadvantage is that the rechargeable battery enables an electric vehicle to only run for a limited number of miles before requiring electric charging. To solve these problems, the hybrid vehicle has been developed by combining environmental sustainability with the high performance of a conventional internal combustion engine. In this study, an electric UTV (Utility Terrain Vehicle) was transformed into a hybrid vehicle system by outfitting the vehicle with a drive auxiliary power system including a 125 cc internal combustion engine. This modification enabled us to extend the range of the hybrid UTV from 50km to 100km per one electric charging.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.2
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• pp.1-14
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• 2021

It is highly challenging to measure the efficiency of electric vehicle charging stations (EVCSs) because factors affecting operational characteristics of EVCSs are time-varying in practice. For the efficiency measurement, environmental factors around the EVCSs can be considered because such factors affect charging behaviors of electric vehicle drivers, resulting in variations of accessibility and attractiveness for the EVCSs. Considering dynamics of the factors, this paper examines the technical efficiency of 622 electric vehicle charging stations in Seoul using data envelopment analysis (DEA). The DEA is formulated as a multi-period output-oriented constant return to scale model. Five inputs including floating population, number of nearby EVCSs, average distance of nearby EVCSs, traffic volume and traffic congestion are considered and the charging frequency of EVCSs is used as the output. The result of efficiency measurement shows that not many EVCSs has most of charging demand at certain periods of time, while the others are facing with anemic charging demand. Tobit regression analyses show that the traffic congestion negatively affects the efficiency of EVCSs, while the traffic volume and the number of nearby EVCSs are positive factors improving the efficiency around EVCSs. We draw some notable characteristics of efficient EVCSs by comparing means of the inputs related to the groups classified by K-means clustering algorithm. This analysis presents that efficient EVCSs can be generally characterized with the high number of nearby EVCSs and low level of the traffic congestion.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.3
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• pp.566-571
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• 2011

As Plug-in Hybrid Vehicle and Electric Vehicle (PHEV/EV) take a greater share in the personal automobile market, their high penetration levels may bring potential challenges to electric utility especially at the distribution level. Thus, there is a need for the flexible charging management strategy to compromise the benefits of both PHEV/EV owners and power grid side. There are many different management methods that depend on the objective function and the constraints caused by the system. In this paper, the schema and dispatching schedule of centralized PHEV/EV charging spot network are analyzed. Also, we proposed and compared three power allocation strategies for centralized charging spot. The first strategy aims to maximize state of vehicles at plug-out time, the rest methods are equalized allocation and prioritized allocation based on vehicles SoC. The simulation results show that each run of the optimized algorithms can produce the satisfactory solutions to response properly the requirement from PHEV/EV customers.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.68-70
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• 2021

The wind power generators installed in the Jeju area have already exceeded the supply in the Jeju area and are being thrown away. Accordingly, the government is conducting research on installing a 2MWh-class ESS(energy storage system) through a technology development project to charge wasted power and use it in an electric vehicle charging station. In this paper, in order to stably install a 2MWh class ESS, the electric vehicle charging model and ESS discharge model were modeled and simulated using Matlab Simulink. Through simulation, it was verified that the 2MWh class ESS operates stably in various scenarios.

• Proceedings of the KIEE Conference
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• 1999.11c
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• pp.570-572
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• 1999

An equivalent circuit model of vehicle charging-discharging system for simulation is developed. The vehicle electric power system consists of alternator and battery. The alternator must have adequate capacity for providing electric energy to all loads, and the battery supports the alternator by offering insufficient energy when the alternator output energy is not enough. The alternator model is simplified for the use of characteristic curve, which was provided by its manufacturer, and the battery model is separated in charging mode and discharging mode because of its complex characteristics. Developed circuit model is validated by comparing the simulation data and real experimental data.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.6_1
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• pp.985-991
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• 2023

This study proposes a solution to the voltage drop in electric vehicle chargers, due to the parasitic resistance and inductance of power cables when the chargers are separated by large distances. A method using multi-level electric vehicle chargers that can output power in stages, without installing an additional energy supply source such as a reactive power compensator or an energy storage system, is proposed. The voltage drop over the power cables, to optimize the charging scheduling, is derived. The obtained voltage drop equation is used to formulate the constraints of the optimization process. To validate the effectiveness of the obtained results, an optimal charging scheduling is performed for each period in a case study based on the assumed charging demands of three connected chargers. From the calculations, the proposed method was found to generate an annual profit of $20,800 for a $12,500 increase in installation costs.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.64-65
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• 2017

This paper review the core technical trends of TESAL EV(Electric Vehicle) Motors. The object of this study analyzes electric vehicle's body appearance, motor cooling system, battery arrangement, battery management system (BMS), and super charging station etc.