Interleaved Buck Converter having low switching losses and improved step-down conversion ratio

Il-Oun Lee,Shin-young Cho,Gun-Woo Moon 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

A new interleaved buck converter (IBC) having low switching losses and improved step-down conversion ratio is proposed in this paper. It is similar to a conventional IBC, but two active switches are connected in series, and a coupling capacitor is employed in the power path, like Cuk, Sepic, and Zeta converters. The proposed IBC shows that since the voltage stress across all active switches is half of the input voltage before turn-on or after turn-off, the capacitive discharging and switching losses can be reduced considerably. This allows the proposed IBC to have higher efficiency and be operated at higher switching frequency. In addition, the proposed IBC has higher step-down conversion ratio and smaller output current ripple than a conventional IBC. The features, operation principles, and relevant analysis results of the proposed IBC are presented in this paper. The validity of this study is confirmed by the experimental results of prototype converters with 150-200V input, 24V/10A output.

Phase-Shifted PWM Converter With a Wide ZVS Range and Reduced Circulating Current

Il-Oun Lee,Gun-Woo Moon IEEE 2013 IEEE TRANSACTIONS ON POWER ELECTRONICS - Vol.28 No.2

<P>A phase-shifted (PS) pulse-width-modulation (PWM) converter that can solve the drawbacks of existing PS full-bridge converters, such as narrow zero-voltage-switching (ZVS) range, large duty-cycle loss, large circulating current, and serious secondary-voltage overshoot and oscillation, is proposed in this paper. The proposed converter is composed of two symmetric half-bridge converters (TSHBCs) that are placed in parallel on the primary side and are driven in a phase-shifting manner. Their transformers are connected in series on the secondary side. At the output, a simple energy-recovery circuit (ERC) is employed. Due to this structure, the proposed converter has the advantages of wide ZVS range, less duty-cycle loss, reduced circulating current, and no secondary-voltage overshoot and oscillation, which results in the reduction of rectifier diodes' voltage stress and EMI. Therefore, the conversion efficiency is higher and the cost of the secondary rectifier is reduced compared to its PS PWM counterparts. In this paper, the circuit configuration, operation principle, and relevant analysis results of the proposed converters are presented. Experimental results on a prototype converter realized with an 80-in plasma display panel sustain power module (320-385 V<SUB>dc</SUB> input, 205 V<SUB>dc</SUB>/5 A output) validate the theoretical analysis.</P>

Half-Bridge Integrated ZVS Full-Bridge Converter With Reduced Conduction Loss for Electric Vehicle Battery Chargers

Il-Oun Lee,Gun-Woo Moon Institute of Electrical and Electronics Engineers 2014 IEEE transactions on industrial electronics Vol. No.

<P>A half-bridge integrated zero-voltage-switching (ZVS) full-bridge converter with reduced conduction loss for battery on-board chargers in electric vehicles (EVs) or plug-in hybrid electric vehicles (PHEVs) is proposed in this paper. The proposed converter features a reduction in primary-conduction loss and a lower secondary-voltage stress. In addition, the proposed converter has the most favorable characteristics as battery chargers as follows: a full ZVS capability and a significantly reduced output filter size due to the improved output waveform. In this paper, the circuit configuration, operation principle, and relevant analysis results of the proposed converter are described, followed by the experimental results on a prototype converter realized with a scale-downed 2-kW battery charger for EVs or PHEVs. The experimental results validate the theoretical analysis and show the effectiveness of the proposed converter as battery on-board chargers for EVs or PHEVs.</P>

Three-Level LLC SRC for High and Wide Input Voltage Applications

Il-Oun Lee,Gun-Woo Moon 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

A new three-level LLC series-resonant-converter (TL LLC SRC) for high and wide input voltage applications is proposed. It consists of two half bridge LLC SRCs in series, sharing a resonant inductor and a transformer. The main advantages of the proposed converter are that the voltages across all switches clamp to half of the input voltage and keep the balance. Thus, it is suitable for high input voltage applications. Moreover, due to its simple driving signals, the additional circulating current of the conventional TL LLC SRCs does not appear in the converter, and driving circuitry can be designed to be simpler. The validity of this study is confirmed by the experimental results of a prototype converter with 400-600V input, 48V/20A output.

A Hybrid PWM-Resonant DC-DC Converter for Electric Vehicle Battery Charger Applications

Il-Oun Lee 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.5

In this paper, a new hybrid DC-DC converter is proposed for electric vehicle 3.3 kW on-board battery charger applications, which can be modulated in a phase-shift manner under a fixed frequency or frequency variation. By integrating a half-bridge (HB) LLC series resonant converter (SRC) into the conventional phase-shift full-bridge (PSFB) converter with a full-bridge rectifier, the proposed converter has many advantages such as a full soft-switching range without duty-cycle loss, zero-current-switching operation of the rectifier diodes, minimized circulating current, reduced filter inductor size, and better utilization of transformers than other hybrid dc-dc converters. The feasibility of the proposed converter has been verified by experimental results under an output voltage range of 250-420V dc at 3.3 kW.

The <tex> $k$</tex>-Q Analysis for an LLC Series Resonant Converter

Il-Oun Lee,Gun-Woo Moon IEEE 2014 IEEE transactions on power electronics Vol.29 No.1

<P>The k-Q analysis of the resonant tank for an LLC series-resonant converter (SRC) is presented in this letter. In order to guarantee the LLC-SRC operating region, the k-Q design guideline of the resonant tank is proposed.</P>

Soft-Switching DC/DC Converter With a Full ZVS Range and Reduced Output Filter for High-Voltage Applications

Il-Oun Lee,Gun-Woo Moon IEEE 2013 IEEE transactions on power electronics Vol.28 No.1

<P>A new soft-switching dc/dc converter, which can solve the drawbacks of existing phase-shifted full-bridge converters such as narrow zero-voltage-switching (ZVS) range, large circulating current, large duty-cycle loss, and a large output filter in high-voltage applications, is proposed in this paper. The proposed converter is composed of two symmetric half-bridge inverters that are placed in parallel on the primary side and are driven in a phase-shifting manner to regulate the output voltage. At the rectifier stage, two full-bridge rectifiers sharing two low-current-rating diodes are employed. This structure allows the proposed converter to have the advantages of a full ZVS range, no problems related to duty-cycle loss, no circulating current, and a significantly reduced output filter. In this paper, the circuit configuration, operation principle, and relevant analysis results of the proposed converters are presented. Experimental results on a prototype converter realized with the specification of 80-in plasma display panel sustain power module (320-385 V<SUB>dc</SUB> input, 205 V<SUB>dc</SUB>/5 A output) validate the theoretical analysis.</P>

A Hybrid PWM-Resonant DC-DC Converter for Electric Vehicle Battery Charger Applications

Lee, Il-Oun The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.5

In this paper, a new hybrid DC-DC converter is proposed for electric vehicle 3.3 kW on-board battery charger applications, which can be modulated in a phase-shift manner under a fixed frequency or frequency variation. By integrating a half-bridge (HB) LLC series resonant converter (SRC) into the conventional phase-shift full-bridge (PSFB) converter with a full-bridge rectifier, the proposed converter has many advantages such as a full soft-switching range without duty-cycle loss, zero-current-switching operation of the rectifier diodes, minimized circulating current, reduced filter inductor size, and better utilization of transformers than other hybrid dc-dc converters. The feasibility of the proposed converter has been verified by experimental results under an output voltage range of 250-420V dc at 3.3 kW.

전기자동차 탑재형 충전기 응용에서 위상변조 풀브리지 컨버터 성능 분석과 그 개선에 관한 연구

이일운(Il-Oun Lee) 전력전자학회 2015 전력전자학회 논문지 Vol.20 No.5

개선된 ZVT 부스트 컨버터

이일운(Il-Oun Lee),이동영(Dong-Young Lee),조보형(Bo-Hyung Cho) 전력전자학회 2001 전력전자학술대회 논문집 Vol.2001 No.7

In this paper, the improved zero-voltage transition(ZVT) PWM boost converter using an inductor feedback technique is proposed. The improved circuit uses a low-voltage zener diode to reduce the turn-off switching loss of the auxiliary switch and EMI noise. Using this technique, soft-switching for the auxiliary switch is guaranted at wide line and load ranges and some of the energy circulating in the auxiliary circuit is fed to the load. Since the active switches are turned on and off softly, the switching losses and EMI noise are reduced significantly and the higher efficiency of the system is achieved. In this paper, the modes of converter operation are explained and analyzed, design guidelines are given, and experimental results of 1kW, 100kHz prototype system are presented.