• 전력전자학회논문지
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• 제20권5호
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• pp.479-490
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• 2015

The conventional phase-shifted full-bridge (PSFB) converter with an LC filter has been widely used for high-power applications of over 1.0 kW. However, the PSFB converter cannot obtain optimal power conversion efficiency during the battery charging in electric vehicle (EV) on-board battery charger applications because of its unique drawbacks, such as a large circulating current and very high voltage stress in the rectifier diodes. As a result, the converters with a capacitive filter, such as LLC resonant converters, replace the PSFB converter in the EV chargers. This study analyzes the problems of the PSFB converter for EV on-board charger applications in detail. Moreover, the newest converters based on the conventional PSFB converter are reviewed. On the basis of the reviews, new PSFB converter topologies are proposed for EV charger applications. The new topologies are formed by connecting the rectifier stage in the PSFB converter with the output of an LLC resonant converter in series. Many problems of the conventional PSFB converter for EV charger applications can be solved and the performance can be more improved because of this structure; this idea is confirmed by an experiment consisting of prototype battery chargers under the output voltage range of 250-450 Vdc at 3.3 kW.

• 전기학회논문지
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• 제65권12호
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• pp.2225-2231
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• 2016

In order to overcome the problem of fossil fuel energy, electric vehicle (EV) has been used in recent years. The important issues of EV are driving distance and lifetime related to EV efficiency. A voltage source converter is one of the main components of EV which can be operated with various pulse width modulation (PWM) schemes such as continuous PWM schemes and discontinuous PWM schemes. These PWM schemes will cause the effects on the efficiency of converter system and the lifetime of EV. Therefore, this paper proposes an analysis of the PWM schemes for the power converter on the EV. The objective is to find out a best solution for the EV by comparing the total harmonic distortion (THD) and transient response between the various PWM schemes. The operation of traction motor on the EV with the PWM schemes will be verified by using Psim simulation program.

• 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.

• 전력전자학회논문지
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• 제25권6호
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• pp.425-432
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• 2020

The phase-shifted, full-bridge (PSFB) DC-DC converter is widely used in electric vehicles (EVs) to charge a low-voltage (12 V) battery from a high-voltage battery. A Photovoltaic (PV) module-integrated PSFB converter is proposed for the EV power conversion system. The converter is useful because solar energy can be utilized to extend the driving range. The buck converter circuit is simply realized by adding one switch to the conventional PSFB converter's secondary side. For the inductor and diode, the existing components in the PSFB converter are shared. The proposed converter can charge a low-voltage battery from the PV module with maximum power point tracking. In addition, the two power sources can be used simultaneously, and efficiency is increased by reducing the circulating current, which is a problem for the conventional PSFB converter.

• 전력전자학회논문지
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• 제20권1호
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• pp.31-37
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• 2015

This paper proposes a 3.3-kW bi-directional EV charger with V2G and V2H functions. The bi-directional EV charger consists of a DC-DC converter and a DC-AC inverter. The proposed EV charger is suitable for wide battery voltage control due to the two-stage configuration of the DC-DC converter. By employing a fixed-frequency series loaded resonant converter as the isolated DC-DC converter, zero-current-switching can be achieved regardless of battery voltage variation, load variation, and power flow. A 3.3-kW prototype of the proposed EV charger has been built and verified with experiments, and indicates a maximum efficiency of 94.39% and rated efficiency of 94.23%.

• Journal of international Conference on Electrical Machines and Systems
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• 제3권4호
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• pp.415-421
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• 2014

In this paper, reactorless high efficiency boost DC/DC converter for EV is proposed. In proposed converter, improves efficiency because decrease power loss when the switches are turned on/off using zero current switching (ZCS) at all switch of primary full bridge. By replacing reactance ingredients of L-C resonance circuit for ZCS with leakage inductance ingredients of high frequency transformer, it reduces system size and expense because of not add special reactor. For validity verification of proposed converter, in the paper implements simulation using PSIM and perform experiment by making 5KW DC/DC converter. In experimental results, efficiency of proposed converter conformed superiority.

• 전기학회논문지P
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• 제61권2호
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• pp.59-66
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• 2012

Recently, the market of Electric Vehicle(EV) is increasing more and more than before. Thus a new heater for the EV is required. The PTC devices may be used the heater for the EV. In this paper, a simple DC-DC Converter is proposed as the PTC Heater for the EV. The proposed circuit was optimally desired to decrease the stress of the power devices and reduce the current ripples. To apply the result of the test in the laboratory to the actual EV system with the high DC voltage, ripple current, average current and output peak current are predicted by using the least-squares method. Finally, the proposed circuit is validated by various experiments.

• 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.

• 전력전자학회논문지
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• 제15권2호
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• pp.127-133
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• 2010

본 논문에서는 전기자동차용 리액터리스 고효율 승압형 DC/DC컨버터를 제안한다. 제안한 컨버터는 1차측 Full Bridge의 모든 스위치에서 영전류 스위칭을 적용하여 턴 온/턴 오프시 스위칭 소자에 생기는 전력 손실을 감소시키므로서 효율을 개선한다. 그리고 ZCS(Zero Current Switching)를 위한 L-C공진 회로 중 리액턴스 성분을 1, 2차 절연을 위한 고조파 변압기의 누설인덕턴스 성분으로 대체함으로서 별도의 리액터를 추가하지 않기에 시스템 사이즈 및 비용을 줄일 수 있다. 제안된 컨버터의 타당성 검증을 위하여 본 논문에서는 PSIM을 이용하여 시뮬레이션을 수행하였으며 실제 5[KW]급 DC/DC컨버터를 제작하여 실험을 수행하였다. 실험결과 제안된 컨버터의 효율이 매우 우수함을 확인하였다.

• 전력전자학회논문지
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• 제20권6호
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• pp.566-572
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• 2015

This study introduces an LCC resonant converter operating on a continuous conduction mode. The LCC resonant converter has the advantage of improving system efficiency, especially under the rated load condition, because it can reduce conduction loss by improving the resonance current shape and switching loss by increasing the lossless snubber capacitance. The proposed LCC resonant converter is applied to various applications, including a 60 kW EV fast charger, a 24 kJ/s high-voltage capacitor charger, and a 20 kV, 20 kW high-precision DC power supply. Experimental results prove that the proposed LCC resonant converter topology can be effectively used as a converter topology for these applications.