• Journal of Electrical Engineering and Technology
• /
• v.11 no.4
• /
• pp.860-868
• /
• 2016

A bidirectional DC-DC converter (BDC) is an indispensable electrical unit for the electric vehicles (EVs). High efficiency, high power density, isolation, light weight and reliability are all essential requirements for BDC. In this paper, a 3 kW BDC for the battery charger of EVs is proposed. The proposed converter consists of a half-bridge structure on the primary side and an isolation transformer and a synchronous rectifier structure on the secondary side. With this topology, minimum number of switching devices are required for bidirectional power flow between the two dc buses of EVs. The easy implementation of the synchronous rectification gives advantages in terms of efficiency, cost and flexibility. The proposed BDC achieves high efficiency when operating in both modes (step-up and step-down). A 3 kW prototype is implemented to verify theoretical analysis and the performance of the proposed converter.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.49 no.9
• /
• pp.590-597
• /
• 2000

Design of single state AC-DC converter with high power factor for low level applications is proposed. The proposed converter is obtained from the integration of a buck-boost converter and the half-bridge DC-DC converter. This converter gives the good power factor correction low line current harmonic distortions and tight output voltage regulations. This converter also has a high efficiency by employing an soft switching method and synchronous rectifier. The modelling and detailed analysis for the proposed converter are performed. To verify the performance of the proposed converter a 100W converter has been designed

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.53 no.4
• /
• pp.166-170
• /
• 2004

In this paper, it has been proposed the simultaneous control of PFC (power factor corrector) and electronic ballast for fluorescent lamp by one chip micro-controller. Boost DC-DC converter is adopted for PFC, and half bridge inverter for electronic ballast. It controls, simultaneously and independently, the boost DC-DC converter and the half bridge inverter. As PFC and electronic ballast are controlled by one chip micro-controller, it is possible to achieve the simpler and the cheaper controller for fluorescent lamp. Experimental results have shown the feasibility of the proposed simultaneous control of PFC and electronic ballast by one chip micro-controller.

• Proceedings of the KIEE Conference
• /
• 2005.10a
• /
• pp.118-121
• /
• 2005

In this paper, it has been proposed the simultaneous controller of electronic ballast and PFC(power factor corrector) for fluorescent lamp by one chip micro-controller. Boost DC-DC converter is adopted for PFC, and half bridge inverter for electronic ballast. It controls, simultaneously and independently, the boost DC-DC converter and the half bridge inverter. As electronic ballast and PFC are controlled by one chip micro-controller, it is possible to achieve the cheaper controller for fluorescent lamp. Experimental result has shown the feasibility of the proposed simultaneous controller of PFC and electronic ballast.

• Journal of Power Electronics
• /
• v.11 no.4
• /
• pp.561-567
• /
• 2011

This paper presents a high-efficiency power conditioning system (PCS) for grid-connected photovoltaic (PV) modules. The proposed PCS consists of a step-up DC-DC converter and a single-phase DC-AC inverter for the grid-connected PV modules. A soft-switching step-up DC-DC converter is proposed to generate a high DC-link voltage from the low PV module voltage with a high-efficiency. A DC-link voltage controller is presented for constant DC-link voltage regulation. A half-bridge inverter is used for the single-phase DC-AC inverter for grid connection. A grid current controller is suggested to supply PV electrical power to the power grid with a unity power factor. Experimental results are obtained from a 180 W grid-connected PV module system using the proposed PCS. The proposed PCS achieves a high power efficiency of 93.0 % with an unity power factor for a 60 Hz / 120 Vrms AC power grid.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.23 no.5
• /
• pp.352-358
• /
• 2018

A split-capacitor (SC) dual-active-bridge (DAB) converter is proposed in this study. The DC-link capacitors of input and output are split in the proposed converter. The primary and secondary windings of transformer are connected to the midpoints of the DC-links. Hence, the SC DAB converter can inherently prevent transformer from saturation. Although the switch current stress of the proposed converter is twice that of the conventional DAB converter, the switch voltage stress is reduced by half. Therefore, the proposed converter can reduce switching loss and achieve high efficiency in a high switching frequency. Given the SC structure, the proposed converter can readily be connected to neutral-point-clamped- or half-bridge-type converters. The topology of the proposed converter is presented and the operating principle is analyzed in detail. A 3-kW hardware prototype was built and tested to verify the performance of the proposed converter.

• Proceedings of the KIPE Conference
• /
• 2006.06a
• /
• pp.372-374
• /
• 2006

This paper reported the experimental results of the 2 stage converter using a Buck converter and a soft switching dc-to-dc converter that employs two separate transformers. A 2 stage converter module is designed with the specifications of an 3.3V output voltage, 20A output current, 66W output power and 36-75V input voltage. A prototype converter module is successfully implemented within 85.2% efficiency and 3% voltage regulation for the entire input voltage range, thereby demonstrating its application potentials to future telecommunication electronics.

• Proceedings of the KIPE Conference
• /
• 2002.07a
• /
• pp.538-541
• /
• 2002

Dynamic analysis and compensation design for an asymmetrical half bridge do-dc converter are presented. A small-signal model is developed using the averaging method. Based on the proposed small-signal average model, the open loop transfer functions of the power stage were obtained and used for the compensation design. All theoretical predictions are validated by experiments on a prototype converter.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.14 no.2
• /
• pp.52-58
• /
• 2000

This paper presents a novel power factor corrected(PFC) single-stage AC/DC half-bridge converter, which features discontinuous conduction mode(DCM) and soft-switching. The reduced conduction losses are achieved by the employment of a novel powder factor correction circuitry, instead of the conventional configuration composed of a front-end rectifier followed by a boost converter. To identify the validity of the proposed converter, simulated results of 500[W] converter with 100[V] input voltage and 50[V]output voltage are presented.

• Proceedings of the KIEE Conference
• /
• 2009.07a
• /
• pp.987_988
• /
• 2009

견인용 시스템에 있어서 구동모터의 효율증대를 위해서는 고압전원이 필수적이며 이를 위해 일반적으로 승압 DC/DC 컨버터 사용하고 있으나, Hard Switching 방식의 PWM 컨버터로는 효율향상에 한계가 있으며 동특성이 저하되는 단점이 있다. 본 논문에서는 새로운 방식의 절연된 차량용 고압 DC/DC 컨버터를 이용하여 효율 및 동특성을 개선하기위해 Full-bridge 컨버터와 Double-half-bridge 컨버터를 이용한 소프트 스위칭방식으로 고효율화를 달성하고 컨버터의 동특성을 향상시켰다.