• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2003년도 학술대회 논문집
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• pp.43-46
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• 2003

The dc reactor type high-Tc superconducting fault current limiter(SFCL) is composed of three parts, a power converter, a magnetic core reactor(MCR) and a dc reactor. This study concerned with the power converter of the DC reactor type high-Tc SFCL. The rectifying devices which power converter of 6.6kV/200A SFCL consists of have to endure high voltage. We propose the dual mode power converter to reduce the voltage which each rectifying device endures. In the single phase the experiment and simulation of dual mode power converter and the simulation of power converter with one bridge rectifier are performed. The current of each system with different power converter has a same tendency and the voltage which rectifying device of dual mode power converter endures is reduced in half by comparison with that of power converter with one bridge rectifier. We found dual mode power converter can be applied to SFCL.

• 전자공학회논문지
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• 제51권7호
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• pp.111-121
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• 2014

본 논문에서는 무선으로 전력을 수신할 뿐만 아니라 송신 할 수 있는 기능을 수행하는 무선 전력 송수신기를 위한 양방향으로 동작하는 DC-DC converter를 제안하였다. 일반적으로 무선 전력 송수신기의 경우 2개의 DC-DC converter와 이로 인한 2개의 외부 인덕터가 필요하지만 제안된 DC-DC converter를 적용하여 1개의 DC-DC converter와 1개의 외부 인덕터로 무선 전력 송수신이 가능하도록 하여 전체 시스템의 크기를 줄였다. 제안된 양방향으로 동작하는 DC-DC converter는 $0.35{\mu}m$ BCDMOS 공정을 이용하여 제작하였으며 무선 전력 수신 상황에서 강압 converter로 동작하여 3W의 출력 상황에서 91%의 효율을 가지며 무선 전력 송신 상황에서는 승압 converter로 동작하여 3W의 출력 상황에서 90%의 효율을 갖는다. 양방향으로 동작하는 DC-DC converter와 효율을 극대화 할 수 있는 제안된 기법들을 적용한 무선 전력 송수신기는 수신 상황에서 81.7%, 송신 상황에서 76.5%의 효율을 갖는다.

• 전기전자학회논문지
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• 제22권3호
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• pp.767-773
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• 2018

본 논문에서는 높은 역률을 가지는 단순 구조 LED 구동 직류 전력컨버터를 제안한다. 제안한 전력컨버터는 PFC 부스트 컨버터와 전통적인 플라이백 컨버터를 오직 하나의 전력변환 회로로 병합함으로써 LED 구동 전력컨버터의 구조를 단순화한다. 그리하여 제안한 컨버터는 오직 하나의 PWM 제어기 IC를 이용하여 제어되고 높은 역률과 정출력 전압/전류 및 제작비용의 효율성을 달성한다. 따라서 제안한 컨버터는 LED 조명시스템의 산업 생산과 이용에 적합하다. 본 논문에서는 제안한 컨버터의 동작분석과 설계예시를 간단하게 설명한다. 또한 설계된 회로파라미터들에 근거하여 제작된 프로토타입의 실험결과를 통하여 제안한 컨버터의 동작특성을 입증한다.

• Journal of Power Electronics
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• 제15권6호
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• pp.1438-1445
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• 2015

A new DC-DC power converter is researched for renewable energy and battery hybrid power supplies systems in this paper. At the charging mode, a renewable energy source provides energy to charge a battery via the proposed converter. The operating principle of the proposed converter is the same as the conventional DC-DC buck converter. At the discharging mode, the battery releases its energy to the DC bus via the proposed converter. The proposed converter is a non-isolated high step-up DC-DC converter. The coupled-inductor technique is used to achieve a high step-up voltage gain by adjusting the turns ratio. Moreover, the leakage-inductor energies of the primary and secondary windings can be recycled. Thus, the conversion efficiency can be improved. Therefore, only one power converter is utilized at the charging or discharging modes. Finally, a prototype circuit is implemented to verify the performance of the proposed converter.

• Journal of Power Electronics
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• 제19권1호
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• pp.220-233
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• 2019

This work aims to study and analyze the various operating modes of universal power converter which is powered by solar and thermoelectric generators. The proposed converter is operated in a DC-DC (buck or boost mode) and DC-AC (single phase) inverter with high efficiency. DC power sources, such as solar photovoltaic (SPV) panels, thermoelectric generators (TEGs), and Li-ion battery, are selected as input to the proposed converter according to the nominal output voltage available/generated by these sources. The mode of selection and output power regulation are achieved via control of the metal-oxide semiconductor field-effect transistor (MOSFET) switches in the converter through the modified stepped perturb and observe (MSPO) algorithm. The MSPO duty cycle control algorithm effectively converts the unregulated DC power from the SPV/TEG into regulated DC for storing energy in a Li-ion battery or directly driving a DC load. In this work, the proposed power sources and converter are mathematically modelled using the Scilab-Xcos Simulink tool. The hardware prototype is designed for 200 W rating with a dsPIC30F4011 digital controller. The various output parameters, such as voltage ripple, current ripple, switching losses, and converter efficiency, are analyzed, and the proposed converter with a control circuit operates the converter closely at 97% efficiency.

• Journal of Power Electronics
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• 제5권4호
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• pp.247-256
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• 2005

In order to harvest power in an efficient manner from a micro piezoelectric (PZT) device for charging the battery of a remote system, a new AC/DC resonant pulse power converter is proposed. The proposed power converter has two stages in the power conversion process. The first stage includes N-type MOSFET full bridge rectifier. The second stage includes a boost converter having an N-type MOSFET and a P-type MOSFET. MOSFETs work in the $1^{st}$ or $3^{rd}$ quadrant region. A small inductor for the boost converter is assigned in order to make the size of the power converter as small as possible, which makes the on-interval of the MOSFET switch of the boost converter ultimately short. Due to this short on-interval, the parasitic junction capacitances of MOSFETs affect the performance of the power converter system. In this paper, the performance of the new converter is analytically and experimentally evaluated with consideration of the parasitic capacitance of switching devices.

• Journal of Electrical Engineering and Technology
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• 제5권3호
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• pp.468-476
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• 2010

This paper presents a direct single-stage power converter using single-phase isolated full-bridge converter modules, with inherent power factor correction (PFC) for a 12 kW switched mode power supply (SMPS). The advantages of the proposed converter are its simple control strategy, reduction in number of conversion stage, low input line current harmonics, and improvement in power factor. Analysis of the single-stage converter is carried out in continuous conduction mode of operation. Steady-state analysis of the proposed converter is conducted to obtain converter parameters. A systematic design procedure is also presented for a 12k W converter with a design example. The effect of load variation on SMPS is also studied in order to demonstrate the effectiveness of the proposed converter for the complete range of load conditions. A set of power quality indices on input ac mains for an SMPS fed from a single-stage converter is also presented for easy comparison of their performance.

• 전력전자학회논문지
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• 제19권1호
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• pp.23-30
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• 2014

This paper proposes a single power-conversion ac-dc converter with a dc-link capacitor-less and high power factor. The proposed converter is derived by integrating a full-bridge diode rectifier and a series-resonant active-clamp dc-dc converter. To obtain a high power factor without a power factor correction circuit, this paper proposes a suitable control algorithm for the proposed converter. The proposed converter provides single power-conversion by using the proposed control algorithm for both power factor correction and output control. Also, the active-clamp circuit clamps the surge voltage of switches and recycles the energy stored in the leakage inductance of the transformer. Moreover, it provides zero-voltage turn-on switching of the switches. Also, a series-resonant circuit of the output-voltage doubler removes the reverse-recovery problem of the output diodes. The proposed converter provides maximum power factor of 0.995 and maximum efficiency of 95.1% at the full-load. The operation principle of the converter is analyzed and verified. Experimental results for a 400W ac-dc converter at a constant switching frequency of 50kHz are obtained to show the performance of the proposed converter.

• 전력전자학회논문지
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• 제27권2호
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• pp.157-164
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• 2022

This study proposes an enhanced quadruple-Active-Bridge (QAB) converter that can solve power coupling problems. By adopting a multiple winding transformer, the equivalent circuit of a conventional QAB converter has power couplings between arbitrary output ports. This coupling is an unintended power relationship that complicates the regulation of output voltage of the multiple ports. The proposed converter can carry out power decoupling by changing the arrangement of the coupling inductor. Power transfer equations for the proposed converter and its operating principles are analyzed in detail. The power coupling caused by the transformer's leakage inductance is verified by using a proposed coupling factor that presents the relationship between inductance ratio and coupling power. In addition, the decoupling power control performance of the proposed converter is verified by simulation and a 3 kW prototype converter.

• Journal of electromagnetic engineering and science
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• 제11권3호
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• pp.161-165
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• 2011

In this paper, a high-efficiency DC-AC converter is used for wireless energy transmission. The DC-AC convertter is implemented by combining the oscillator and power amplifier. Given that the conversion efficiency of a DC-AC converter is strongly affected by the efficiency of the power amplifier, a high-efficiency power amplifier is implemented using a class-E amplifier structure. Also, because of the low output power of the oscillator connected to the input stage of the power amplifier, a high-gain two-stage power amplifier using a drive amplifier is used to realize a high-output power DC-AC converter. The high-efficiency DC-AC converter is realized by connecting the oscillator to the input stage of the high-gain high-efficiency two-stage class-E power amplifier. The output power and the conversion efficiency of the DC-AC converter are 40.83 dBm and 87.32 %, respectively, at an operation frequency of 13.56 MHz.