• 한국산학기술학회논문지
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• 제21권12호
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• pp.77-86
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• 2020

기존의 고정형 EV(electric vehicle) 충전기는 이용률이 증가하게 되면 충전 인프라 설비 부족으로 인해 사용자의 충전 대기시간이 길어지는 불편함이 발생할 수 있고, EV 충전기를 증설하는 경우, 배전선로(지중) 증설비용 및 선로의 전압강하로 인한 전력품질 문제가 발생할 수 있다. 따라서, 본 논문에서는 상기의 문제점을 해결하고, EV 충전기 부족으로 인한 불편함을 해결할 수 있는 EV용 이동형 전원공급장치(movable power supply device, MPSD)를 제안한다. 제안한 MPSD는 태양광전원부, 에너지저장부, EV용 충전기부, 감시제어부로 구성되고, 사용자의 환경요소에 따라 MPSD를 유연하게 이용할 수 있도록 3가지 운용모드로 나눌 수 있다. 또한, 경제성 평가 모델링을 비용요소와 편익요소로 구분한다. 여기서, MPSD의 비용요소로는 태양광전원부, 에너지저장부, EV 충전기부, 감시제어부의 설비비용과 기존의 EV 충전기 설비비용, 배전선로 증설비용, 기존의 EV 충전기 운용비용등의 편익요소로 구성되며, 이를 바탕으로 현재 가치 환산법을 사용하여 경제성을 평가한 결과, MPSD가 기존의 고정형 EV 충전기보다 유리함을 알 수 있었고, 설치지점의 거리에 따라 편익이 크게 좌우함을 확인하였다.

• 한국초전도ㆍ저온공학회논문지
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• 제16권3호
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• pp.21-25
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• 2014

As wireless power transfer (WPT) technology using strongly coupled electromagnetic resonators is a recently explored technique to realize the large power delivery and storage without any cable or wire, this technique is required for diffusion of electric vehicles (EVs) since it makes possible a convenient charging system. Typically, since the normal conducting coils are used as a transmitting coil in the CPT system, there is limited to deliver the large power promptly in the contactless EV charging system. From this reason, we proposed the combination CPT technology with HTS transmitting antenna, it is called as, superconducting contactless power transfer for EV (SUWPT4EV) system. As the HTS coil has an enough current density, it can deliver a mass amount of electric energy in spite of a small scale antenna. The SUCPT4EV system has been expected as a noble option to improve the transfer efficiency of large electric power. Such a system consists of two resonator coils; HTS transmitting antenna (Tx) coil and normal conducting receiver (Rx) coil. Especially, the impedance matching for each resonator is a sensitive and plays an important role to improve transfer efficiency as well as delivery distance. In this study, we examined the improvement of transmission efficiency and properties for HTS and copper antennas, respectively, within 45 cm distance. Thus, we obtained improved transfer efficiency with HTS antenna over 15% compared with copper antenna. In addition, we achieved effective impedance matching conditions between HTS antenna and copper receiver at radio frequency (RF) power of 370 kHz.

• 한국정보전자통신기술학회논문지
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• 제14권1호
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• pp.91-97
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• 2021

전기자동차를 이용하여 계통에 전력을 공급하는 Vehicle to Grid(V2G)의 구현을 위한 통신표준으로 ISO/IEC 15118이 적용되고 있다. 통신 프로토콜에 기반을 두는 전기자동차의 충방전 제어 시에 필연적으로 충방전 실행까지의 시간지연이 발생하게 되는데, 이러한 시간지연은 전력 유연성 공급 측면에서 제한의 요인이 된다. 본 연구에서는 ISO/IEC 15118 기반 V2G 에뮬레이터를 구현하고 전기 자동차 충방전 제어에 따른 반응성을 확인하였다. 실험결과 시간지연은 0.12ms로 나타났으며, 이를 기반으로 현 표준 하에서 참여 가능한 전력 유연성 시장에 대하여 검토하였다.

• 전력전자학회논문지
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• 제27권3호
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• pp.237-246
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• 2022

This paper proposes a method to adjust the turn ratio of a transformer for the high-efficiency operation of an LLC converter with a wide input range in a wired/wireless integrated charging system for electric vehicles. The characteristics of the inductive power transfer converter in the integrated charging system are analyzed to design the LLC converter, and the DC-link voltage range is derived. The aspect of voltage gain following each parameter of the LLC converter is analyzed, and the resonant network and transformer are designed. Based on the designed parameters, the feasibility of the design and control method is verified by implementing the operation of the LLC converter according to the DC-link and battery voltages.

• KEPCO Journal on Electric Power and Energy
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• 제6권1호
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• pp.21-28
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• 2020

• Journal of Electrical Engineering and Technology
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• 제9권1호
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• pp.143-153
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• 2014

This paper presents a novel application of LCC resonant converter for 60kW EV fast charger and describes development of the high efficiency 60kW EV fast charger. The proposed converter has the advantage of improving the system efficiency especially at the rated load condition because it can reduce the conduction loss by improving the resonance current shape as well as the switching loss by increasing lossless snubber capacitance. Additionally, the simple gate driver circuit suitable for proposed topology is designed. Distinctive features of the proposed converter were analyzed depending on the operation modes and detail design procedure of the 10kW EV fast charger converter module using proposed converter topology were described. The proposed converter and the gate driver were identified through PSpice simulation. The 60kW EV fast charger which generates output voltage ranges from 50V to 500V and maximum 150A of output currents using six parallel operated 10kW converter modules were designed and implemented. Using 60kW fast charger, the charging experiments for three types of high-capacity batteries were performed which have a different charging voltage and current. From the simulation and experimental results, it is verified that the proposed converter topology can be effectively used as main converter topology for EV fast charger.

• 한국산업융합학회 논문집
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• 제23권2_1호
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• pp.115-124
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• 2020

In wireless power transfer (WPT) system, the conventional compensation topologies only can provide a constant current (CC) or constant voltage (CV) output under their resonant conditions. It is difficult to meet the CC and CV hybrid charging requirements without any other schemes. In this study, a switching hybrid topology (SHT) is proposed for CC and CV electric vehicle (EV) battery charging. By utilizing an additional capacitor and two AC switches (ACSs), a double-side LCC (DS-LCC) and an inductor and double capacitors-series (LCC-S) topologies are combined. According to the specified CC and CV charging profile, the CC and CV charging modes can be flexibly converted by the two additional ACSs. In addition, zero phase angle (ZPA) also can be achieved in both charging modes. In this method, because the operating frequency is fixed, without using PWM control, and only a small number of devices are added, it has the benefits of low-cost, easy-controllability and high efficiency. A 3.3-kW experimental prototype is configured to verify the proposed switching hybrid charger. The maximum DC efficiencies (at 3.3-kW) of the proposed SHT is 92.58%.

• 전력전자학회논문지
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• 제27권3호
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• pp.228-236
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• 2022

The charging methods of electric vehicles are divided into wired charging and wireless charging. Restrictions on the use of charging infrastructure for wireless charging vehicles currently exist because most charging infrastructure uses the wired charging method. Thus, wired and wireless integrated charging system has been studied. In this system, a wireless charging system especially requires a control method for high-efficiency operation in consideration of a change in a coupling coefficient. Therefore, this paper introduces two control methods for the high-efficiency operation of wireless charging that can be applied to wired and wireless integrated charging systems. In addition, loss analysis is performed through PSIM simulation to select a more advantageous method for high-efficiency operation among the two control methods. To verify the simulation-based loss analysis result, the two control methods are applied to the actual wireless charging system, and the efficiency is compared through the experiments Based on the experimental results, a control method suitable for high-efficiency operation of the wireless charging method is selected.

• 전력전자학회논문지
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• 제23권3호
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• pp.182-189
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• 2018

LLC resonant converters or phase-shift full-bridge converters have been widely used as DC - DC converters for rapid charging of electric vehicles (EVs). However, these converters present critical disadvantages, including a large circulating current, which can hinder efficiency and miniaturization in EV battery charger applications. In this paper, a new DC - DC converter topology is proposed for EV rapid chargers. The proposed converter can operate at high frequency despite a high rated power capacity of over 20kW, and the problem of circulating current can be minimized during the entire battery charging time. Owing to these advantages, the proposed converter can achieve a high conversion efficiency of over 97% for EV rapid charger applications. The performance of the proposed converter is verified with 20kW prototypes in this study.

• 조명전기설비학회논문지
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• 제28권8호
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• pp.98-105
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• 2014

In this paper, we have analyzed the power consumption property of EVs(Electric Vehicles) chargers established in a public place, proposed reasonable demand factors by the number of established EV chargers and its control method in apartments. The optimization of power system and the suppression of the peak load can be controlled through the proposed demand factors and charging scheduling control algorithm. In this paper, electrical design and an case analysis were carried out on a sample apartment complex to prove the effectiveness of the power system. As a result, emergency power transformer capacity has been reduced by approximately 25%, and we have confirmed that the electric rates saving and the control of peak load value is possible.