급속충전기용 파워 모듈을 위한 단일단 AC-DC 컨버터 레덧탕1, 최세완✝ A Single-Stage AC-DC Power Module Converter for Fast-Charger Tat-Thang LE and Sewan Choi-The Transactions of the Korean Institute of Power Electronics, Vol. 27, No. 5, October 2022

 

급속충전기용 파워 모듈을 위한 단일단 AC-DC 컨버터 레덧탕1 , 최세완✝ 

A Single-Stage AC-DC Power Module Converter for Fast-Charger Tat-Thang LE and Sewan Choi

The Transactions of the Korean Institute of Power Electronics, Vol. 27, No. 5, October 2022

 Abstract 

In this study, a single-stage, four-phase, interleaved, totem-pole AC-DC converter is proposed for a super-fast charger station that requires high power, a wide voltage range, and bidirectional operation capabilities and adopts various types of electric transport vehicles. The proposed topology is based on current-fed push-pull dual active bridge converter combined with the totem-pole operation. Owing to the four-phase interleaving effect, the bridge on the grid side can switch at 0.25, 0.5, and 0.75 to achieve a ripple-free grid current. The input filter can be removed theoretically. Switching methods for the duty of the secondary-side duty cycle are proposed, and they correspond to the primary duty cycle for reducing the circulating power and handling the total harmonic distortion. Therefore, the converter can operate under a wide voltage range. Experimental results from a 7.5 kW prototype are used to validate the proposed concept.

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https://www.kstudy.com/fbook/KIPE/27-5/3.pdf

3.3kW Bidirectional OBC Design with Active Clamp Flyback Converter Hyeok-Min Kwon, So-Jeong Kong, Jae-Hyuck Choi, Dae-Young Hong and Jun-Young Lee† Myongji University Electrical Engineering

3.3kW Bidirectional OBC Design with Active Clamp Flyback Converter Hyeok-Min Kwon, So-Jeong Kong, Jae-Hyuck Choi, Dae-Young Hong and Jun-Young Lee† Myongji University Electrical Engineering 

 액티브 클램프 플라이백 컨버터를 이용한 3.3kW 양방향 OBC 설계 권혁민, 공소정, 최재혁, 홍대영, 이준영† 명지대학교 전기공학과 

 ABSTRACT 

본 논문은 3.3kW급 OBC에 사용되는 DC-DC 양방향 Flyback 컨버터를 제안한다. 기존 Flyback 컨버터에서 보조 스 위치를 사용한 회로를 적용하여 변압기 누설 값에 저장된 에너 지를 재활용하여 메인 스위치 전압 스파이크를 최소화하는 방 식을 사용했고 이를 대칭구조로 적용하였다. 모든 전력반도체 소자는 SiC-MOSFET을 적용하였다. 스위칭 주파수 70kHz 조 건에서 입력전압은 400V이며 배터리 전압 100V, 250V, 330V, 450V 네 구간에서 정상 동작을 확인하였으며 정방향 최대 효 율:97.58%, 역방향 최대 효율 97.48%를 달성하였다.

ABSTRACT

This paper proposes a DC-DC bi-directional flyback converter used in a 3.3kW class OBC. In the existing flyback converter, a circuit using an auxiliary switch was applied to recycle the energy stored in the transformer leakage value to minimize the main switch voltage spike, and this was applied in a symmetrical structure. All power semiconductor devices applied SiC-MOSFETs. Under the condition of the switching frequency of 70kHz, the input voltage was 400V, and normal operation was confirmed in four sections of battery voltage 100V, 250V, 330V, and 450V, and the maximum forward efficiency: 97.58% and the maximum reverse efficiency 97.48% were achieved.

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 http://conf2022s.kipe.or.kr/pdfs/output/OS1.2_%EA%B6%8C%ED%98%81%EB%AF%BC.pdf

Three-Phase Single-Stage Bidirectional CCM Soft-Switching AC–DC Converter With Minimum Switch Count-Jaeyeon Lee , Hyeonju Jeong, Tat-Thang LE , Member, IEEE, and Sewan Choi , Fellow, IEEE

Three-Phase Single-Stage Bidirectional CCM Soft-Switching AC–DC Converter With Minimum Switch Count Jaeyeon Lee , Hyeonju Jeong, Tat-Thang LE , Member, IEEE, and Sewan Choi , Fellow, IEEE 

 Abstract—In this article, a three-phase single-stage bidirectional ac–dc converter with low component count is proposed. The single-stage structure is configured by integrating a threephase ac–dc converter and a three-phase dual active bridge converter. The power factor correction and bidirectional power control are performed by adjusting the modulation index of sinusoidal pulse width modulation (SPWM) and phase-shift angle between the primary and secondary bridges. The lowfrequency components generated by SPWM are absorbed by fundamental blocking capacitors connected in series with transformer windings, resulting in true high-frequency isolation. The proposed converter can achieve soft-switching of all switching devices even in continuous conduction mode. A 110 Vac, 3 kW, 100 kHz prototype is implemented to validate the proposed concept and demonstrated 95.34% peak efficiency.

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Compact Integrated Transformer – Grid Inductor Structure for E-Capless Single-Stage EV Charger Ramadhan Muhammad Hakim, Huu-Phuc Kieu, Junyeong Park, Tat-Thang LE, Member, IEEE, Sewan Choi, Fellow, IEEE, Byeongseob Song, Hoyoung Jung, and Bokyung Yoon

Compact Integrated Transformer – Grid Inductor Structure for E-Capless Single-Stage EV Charger Ramadhan Muhammad Hakim, Huu-Phuc Kieu, Junyeong Park, Tat-Thang LE, Member, IEEE, Sewan Choi, Fellow, IEEE, Byeongseob Song, Hoyoung Jung, and Bokyung Yoon 

 Abstract—This paper proposes a planar magnetic integration technique that combines the grid inductors and transformer in the single-stage E-capless EV charger into one core. The proposed integration technique reduces the number of magnetic components; therefore, the cost, total magnetic core loss, and volume can be significantly reduced. Using the integrated structure, the overall converter power density increases up to 11.1% compared to the non-integrated one. This paper also presents a detailed analysis of the optimal PCB winding arrangement considering both AC resistance and winding stray capacitance. Due to the high DC resistance of PCB winding, Litz wire was also considered for the proposed integrated structure. The effectiveness of the proposed structure was validated by implementing it on a 3.7 kW prototype of a single-stage AC-DC converter. Results show that the prototype with the proposed integrated structure achieved higher efficiency with both PCB winding and Litz wire. Peak efficiency of 97.17% and 6.55 kW/L power density were achieved. 

Index Terms—Planar cores, Electric vehicles, Battery chargers, AC-DC power converters

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High voltage insulation design of coreless, planar PCB transformers for multi-MHz power supplies Ole Christian Spro, Student Member, IEEE, Frank Mauseth, Member, IEEE---Department of Electric Power Engineering, Norwegian University of Science and Technology, Trondheim, Norway, Dimosthenis Peftitsis, Senior Member, IEEE

High voltage insulation design of coreless, planar PCB transformers for multi-MHz power supplies Ole Christian Spro, Student Member, IEEE, Frank Mauseth, Member, IEEE, Dimosthenis Peftitsis, Senior Member, IEEE,

 Abstract—This paper investigates the insulation design for printed, planar, coreless, and high-frequency transformers with high isolation-voltage. By using finite element analysis on 2D axial-symmetry, the transformer circuit parameters and electric field distribution are modelled and estimated. Several transformers are designed for an operating frequency of 6.78 MHz. The high frequency, coreless design allows for using thicker insulation material while ensuring a high transformer efficiency. The inclusion of the coupling capacitance in the design optimisation results in several design solutions with the same figure of merit, but with different footprint and isolation voltages. Moreover, high electric fields are identified around the sharp edges of the PCB windings. Finally, the electrical and isolation performance is verified experimentally. The measured electrical properties are close to the simulated values, validating the chosen model. Breakdown tests demonstrate the feasibility of isolation voltage levels up to several tens of kilovolts. The majority of breakdowns occurs at the outer edge of the PCB winding that was identified as a high-field area. Additionally, a concept for grading the electric field of PCB windings is also proposed. Based on the results, the design aspects are discussed in detail for planar, high-frequency isolation transformers with medium-voltage isolation level.

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