• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 B
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• pp.368-371
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• 2000

Two-stage power factor correction (PFC) converter with a single PWM controller is proposed. It consists of a power factor pre-regulator cascaded by an isolated DC/DC converter as in a conventional two-stage approach. However, a single PWM controller is used as in a single-stage, single-switch PFC approach. This converter gives the goof 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. The proposed approach has advantages such as high performance over the single-stage approach and low cost over two-stage approach. The experimental results obtained on a 300W (30V/10A) prototype PFC converter are given to verify the effectiveness of the proposed control method.

• 한국산학기술학회논문지
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• 제14권2호
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• pp.840-845
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• 2013

본 논문에서는 LC 필터 기술을 기반으로 하는 광대역 주파수 이중 하향변환기(Frequency Double Down-Converter)를 설계 및 제작하였다. 설계한 이중 하향변환기는 저잡음 증폭기, 혼합기, IF 증폭기, LC 필터 등으로 구성되며, DC-Block 커패시터와 RF-Bypass 커패시터로 구성된다. 설계 시에 기존 변환기의 능동소자를 수동소자로 구현하였으며 이에 따라 전력감소 및 저가의 비용을 실현할 수 있었다. 측정 결과, 제작한 주파수 이중 하향변환기는 중심 주파수 63MHz 에서 대역폭 100MHz (13~113MHz)인 광대역을 실현하였으며, 이득은 약 40dB 임을 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.90-92
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• 2002

This paper presents an improved C-Dump converter system for switched reluctance motors(SRM). The proposed C-Dump converter derived from the conventional converter for SRM. The proposed converter could overcome the limitation of the conventional C-Dump converter, and could reduce the whole cost of the SRM system since the voltage stress of the dump switch $T_d$ is reduced to $V_{dc}$ when compared with $2V_{dc}$ for the conventional C-Dump converter. The attractive features of the proposed converters are; high-efficient and low-cost, elimination of dump inductor, simple control strategy, smaller size arid light weight. The proposed converter is able to be fast magnetization by $2V_{dc}$, which is sum of the input voltage and charging voltage of the dump capacitor. Also, this topology has many advantages such as freewheeling of phase winding without complex control, reduction of current ripple, reduction of torque ripple, and reduction of switching frequency. Simulation demonstrates the good performance of the converter.

• Journal of Power Electronics
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• 제19권3호
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• pp.645-654
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• 2019

In this paper, a new high step up DC/DC converter with a modified super-lift technique is presented. The coupled inductor technique is combined with the super-lift technique to provide a tenfold or more voltage gain with a proper duty cycle and a low turn ratio. Due to a high conversion ratio, the voltage stress on the semiconductor devices is reduced. As a result, low voltage ultra-fast recovery diodes and low on resistance MOSFET can be used, which improves the reverse recovery problems and conduction losses. This converter employs a passive clamp circuit to recycle the energy stored in the leakage inductance. The proposed convertor features a high conversion ratio with a low turn ratio, low voltage stress, low reverse recovery losses, omission of the inrush currents of the switch capacitor loops, high efficiency, small volume and reduced cost. This converter is suitable for renewable energy applications. The operational principle and a steady-state analysis of the proposed converter are presented in details. A 200W, 30V input, 380V output laboratory prototype circuit is implemented to confirm the theoretical analysis.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2019년도 전력전자학술대회
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• pp.83-85
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• 2019

The use of high voltage gain converters is essential for the distributed power generation systems with renewable energy sources such as the fuel cells and solar cells due to their low voltage characteristics. In this paper, a high voltage gain topology combining cascode Inverting Buck-Boost converter and voltage multiplier structure is introduced. In proposed converter, the input voltage is connected in series at the output, the portion of input power is directly delivered to the load which results in continuous input current. In addition, the voltage multiplier stage stacked in proper manner is not only enhance high step-up voltage gain ratio but also significantly reduce the voltage stress across all semiconductor devices and capacitors. As a result, the high current-low voltage switches can be employed for higher efficiency and lower cost. In order to show the feasibility of the proposed topology, the operation principle is presented and the steady-state characteristic is analyzed in detail. A 380W-40/380V prototype converter was built to validate the effectiveness of proposed converter.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2016년도 추계학술대회 논문집
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• pp.13-14
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• 2016

This paper has introduces a novel Integrated On-board Charger (IOBC) to reduce the size, weight and cost of power conversion stages in Electric Vehicles (EVs). The IOBC is composed of an OBC and a low voltage dc-dc converter (LDC). The IOBC includes a bidirectional ac-dc converter and a bidirectional full-bridge converter with an active clamp circuit. The LDC converter is a hybrid topology combining an active clamped full-bridge converter and a forward converter derived from the Weinburg converter topology. Unlike conventional OBC, the proposed IOBC is compact and the LDC converter of it can achieve a higher efficiency. In addition, the LDC converter of the proposed IOBC can achieve high step-down voltage conversion ratio, no circulating current, no reverse recovery current of the rectifier diodes and small ripple current of output inductor on the auxiliary battery. A 1kW hardware of the LDC converter is implemented to verify the performances of the proposed IOBC.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.1110-1113
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• 2002

A Single-Stage Single-Switch power-factor- correction(PFC) AC/DC Converter with universal input is presented in this paper. The PFC Converter can be achieved based upon the continuous current mode(CCM). The switch has less current and voltage stresses over a wide range of load variation so that a low voltage rating device can be used. The presented converter features high power factor high efficiency, and low cost. An 90W prototype was implemented to show that it has 70% efficiency with low voltage stress over universal line input.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 하계학술대회 논문집
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• pp.188-189
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• 2007

Conventional active-clamp forward converter shows good performance in low power applications, however it suffers from a high voltage stress of switch and is not suitable for high input voltage applications. To solve this problem, a new multi-level active-clamp forward converter is proposed in this paper. Utilizing low rating switches, the proposed converter features high efficiency and low cost promising for high input voltage applications.

• 전기학회논문지
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• 제66권8호
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• pp.1297-1302
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• 2017

Recently, SRMs are used in automobiles for power assistant steering, accessory motion control and traction drives. Especially in the motion control and traction drives, safety and efficiency are of paramount importance. The paper describes the essential elements faced in designing and constructing driving circuits for a switched reluctance motor for automobiles. An important factor in the selection of a motor and a drive for industrial application is the cost. The switched reluctance motor(SRM) is a simple, low-cost, and robust motor suitable for variable-speed as well as servo-type applications. With relatively simple converter and control requirements, the SRM is gaining an increasing attention in the drive industry. This paper presents a modified C-dump converter for Switched Reluctance Motor (SRM) machine application in the cooling system of automobiles. The experiments are performed to verify the capability of applicate control method on 6/4 salient type SRM.

• Journal of Power Electronics
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• 제15권6호
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• pp.1468-1479
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• 2015

Renewable energy resources such as wind and photovoltaic power generation systems demand a high step-up DC-DC converters to convert the low voltage to commercial grid voltage. However, the high step-up converter using a transformer has limitations of high voltage stresses of switches and diodes when the transformer winding ratio increases. Accordingly, conventional studies have been applied to series-connect multioutput converters such as forward-flyback and switched-capacitor flyback to reduce the transformer winding ratio. This paper proposes new single-ended converter topologies of an isolation type and a non-isolation type to improve power efficiency, cost-effectiveness, and output ripple. The first proposal is an isolation-type charge-pump switched-capacitor flyback converter that includes an extreme-ratio isolation switched-capacitor cell with a chargepump circuit. It reduces the transformer winding number and the output ripple, and further improves power efficiency without any cost increase. The next proposal is a non-isolation charge-pump switched-capacitor-flyback tapped-inductor boost converter, which adds a charge-pump-connected flyback circuit to the conventional switched-capacitor boost converter to improve the power efficiency and to reduce the efficiency degradation from the input variation. In this paper, the operation principle of the proposed scheme is presented with the experimental results of the 100 W DC-DC converter for verification.