• Proceedings of the KIPE Conference
• /
• 2013.11a
• /
• pp.5-6
• /
• 2013

본 논문에서는 모바일 기기 등에 사용되는 소형 디스플레이를 위한 고효율 경계모드 탭인덕터 부스트 LED 구동회로를 분석하여 장점을 밝히고 최적의 설계기준을 제시한다.

• Proceedings of the KIPE Conference
• /
• 2013.07a
• /
• pp.38-39
• /
• 2013

본 논문은 고효율의 부스트 컨버터 소프트 스위칭 기법을 제안한다. 제안된 컨버터의 소프트 스위칭 셀은 두 개의 공진 인덕터와 하나의 공진 커패시터, 두 개의 다이오드를 가진다. 소프트 스위칭 셀은 스위치가 항상 영전압 턴 온, 영전류 턴 오프 동작을 하여 스위칭으로 인한 손실이 최소화 되도록 동작한다. 본문에서는 제안된 회로의 동작 특성을 각 모드별로 설명하고, PSIM을 이용하여 검증하였다.

• Journal of Information Display
• /
• v.13 no.2
• /
• pp.73-82
• /
• 2012

In this paper, a light-emitting diode (LED) backlight driver integrated circuit (IC) for medium-sized liquid crystal displays (LCDs) is proposed. In the proposed IC, a linear current regulator with matched internal resistors and an adaptive phase-shifted pulse-width modulation (PWM) dimming controller are also proposed to improve LED current uniformity and reliability. The double feedback loop control boost converter is used to achieve high power efficiency, fast transient characteristic, and high dimming frequency and resolution. The proposed IC was fabricated using the 0.35 ${\mu}m$ bipolar-CMOS-DMOS (BCD) process. The LED current uniformity and LED fault immunity of the proposed IC were verified through experiments. The measured power efficiency was 90%; the measured LED current uniformity, 97%; and the measured rising and falling times of the LED current, 86 and 7 ns, respectively. Due to the fast rising and falling characteristics, the proposed IC operates up to 39 kHz PWM dimming frequency, with an 8-bit dimming resolution. It was verified that the phase difference between the PWM dimming signals is changed adaptively when LED fault occurs. The experiment results showed that the proposed IC meets the requirements for the LED backlight driver IC for medium-sized LCDs.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.928-929
• /
• 2008

A dc/dc power conversion system using multi stage capacitor is proposed in this paper. The proposed new type converter is designed from high efficiency dc/dc converter with fixed boost ratio and variable voltage converter. The tests have been done using PSIM computer simulation to confirm the analysis and control concept.

• Journal of Electrical Engineering and Technology
• /
• v.9 no.2
• /
• pp.541-549
• /
• 2014

In this paper, an extended switched-inductor quasi-Z-source inverter (ESL-qZSI) with high boost voltage inversion ability is presented, which combines the SL-qZSI with the traditional boost converter, as well as improves the switched-inductor cell. Compared with the classic qZSI topologies, the proposed topology reduces the voltage stresses of capacitors, power devices and diodes for the same input and output voltage. Furthermore, the conversion efficiency is improved. The operation principle of the proposed topology is analyzed in details, which is followed by the comparison between the three topologies. In addition, the performance of the proposed topology is verified by simulations and experiments.

• IEIE Transactions on Smart Processing and Computing
• /
• v.5 no.6
• /
• pp.454-461
• /
• 2016

A maximum power point tracking (MPPT) system with fast-tracked time and high power efficiency is presented in this paper. The proposed MPPT system uses an unbounded binary search (UBS) algorithm that continuously tracks the maximum power point (MPP) with a binary system to follow the MPP under rapid-weather-change conditions. The proposed algorithm can decide the correct direction of the MPPT system while comparing the previous power point with the present power point. And then, by fixing the MPP until finding the next MPP, there is no oscillation of voltage MPP, which maximizes the overall power efficiency of the photovoltaic module. With these advantages, this proposed UBS is able to detect the MPP more effectively. This MPPT system is based on a boost converter with a micro-control unit to control analog-to-digital converters and pulse width modulation. Analysis of this work and experimental results show that the proposed UBS MPPT provides fast, accurate tracking with no oscillation in situations where weather rapidly changes and shadow is caused by all sorts of things. The tracking time is reduced by 87.3% and 66.1% under dynamic-state and steady-state operation, respectively, as compared with the conventional 7-bit perturb and observe technique.

• Journal of Energy Engineering
• /
• v.15 no.3 s.47
• /
• pp.181-187
• /
• 2006

This paper is proposed to a solar cell power system used in fire emergency equipment. Also it is designed with a high efficiency power converter in order to increase efficiency of power system. The controlling switches used in DC-DC booster chopper and DC-AC inverter are operated with soft switching, which is applied to resonant circuit method to reduce switching loss. The result is that the system gets to high efficiency. In this paper, A detection circuit of maximum power point of solar cell is described in this paper. And the performance evaluations for the photovoltaic power system of high efficiency are examined by the analysis of a new tracking controller with a maximum power $P_{max}$ detection of solar cell.

• Journal of the Korean Solar Energy Society
• /
• v.36 no.4
• /
• pp.31-40
• /
• 2016

The demands for photovoltaic systems on a large scale have grown dramatically and require new technologies to get the high efficiency and reliable operations of power conversion systems. These needs can be realized by the cost-effective and high performance digital revolutions and faster semiconductor switching devices. However, the new power systems have been more sophisticated and their reliability becomes critical issues. In this paper, a new fault-tolerance power conversion scheme for the photovoltaic systems is proposed. The proposed fault-tolerant scheme is able to supply energy from solar panels to loads intermittently in spite of a front boost converter open failure, and its voltage and current controllers are designed to improve the transient performance by using an average model design scheme. The proposed approach is verified both by simulations. The results will enable more timely and wide usage of alternative/renewable energy systems resulting in increased energy security.

• Proceedings of the KIPE Conference
• /
• 2014.07a
• /
• pp.177-178
• /
• 2014

본 논문은 낮은 전압 스트레스와 고효율을 갖는 탭인덕터 부스트 컨버터를 제안한다. 기존의 탭인덕터 부스트 컨버터는 스위치의 기생 캐패시턴스와 누설 인덕턴스의 공진으로 인하여 반도체 소자에 높은 전압 스트레스가 발생하고 이를 저감하기 위한 손실스너버의 추가로 전력변환효율이 떨어진다. 하지만 제안회로는 손실스너버없이 스위치와 다이오드를 전압원으로 클램핑하여 낮은 전압스트레스를 가진다. 또한, 탭인덕터의 누설인덕턴스를 이용한 스위치의 영전류 스위칭 턴-온과 캐패시터를 이용한 영전압 스위칭 턴-오프로 스위칭 손실을 매우 저감시켜 높은 전력변환효율을 가진다. 제안회로의 타당성을 증명하기 위하여 이론적 해석과 실험결과 제시하였다.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.11 no.3
• /
• pp.540-548
• /
• 2007

The parer proposes a power factor correction high efficiency PWM single-phase rectifier. Its good characteristics such as simple PWM control, low switch stress, and low VAR rating of commutation circuits make the proposed rectifier very suitable for various unidirectional power applications. In addition, the proposed rectifier consists of three boost-converter-type IGBT modules with the switching devices located at the bottom leg of the rectifier scheme, which also enables the use of the same power supply in both control and gate driver, thus resulting in simple control and power circuit structure. The detailed principle of operation and experimental results are also included. In particular, the design guide line is also suggested to make the circuit design of the proposed rectifier easy and fast.