• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.47-48
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• 2012

In generally, grid connected single-phase flyback inverter is operated as boundary or discontinuous conduction mode. However, the flyback inverter can be operated in continuous conduction mode (CCM) due to its operating conditions in spite of it is designed to operate under boundary or discontinuous conduction mode. This situation causes unintended distortion to output current. In this paper, a current shaping method on unfolding bridge to reduce the output current distortion.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.4
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• pp.311-318
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• 2008

This paper proposes synchronous bidirectional DC-DC converter applying soft-switching technique. The proposed converter integrates two advantages which are conduction loss minimization and switching loss elimination by applying interleaved synchronous buck and ZVT-cell with a single resonant inductor. ZVS is guaranteed for wide load range in CCM(Continuous Conduction Mode) as well as wide output voltage range by current injection method. Also, reverse recovery effects of body diode can be minimized. In addition, it is possible to significantly reduce diode drop voltage occurred during dead time of conventional synchronous buck converter. The validity of the proposed converter is verified through experimental results.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.4
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• pp.601-610
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• 2016

The light-emitting diode (LED) has been used in a variety of industrial fields and for general 0lighting purposes on account of its high efficiency, low power consumption and long lifespan. The LED is driven by direct current; therefore, an AC/DC converter is typically required for its use. An electrolytic capacitor is generally used for stabilizing DC voltage during use of the AC/DC converter. However, this capacitor has a short lifespan, which makes it a limiting factor in LED lighting. Furthermore, LED lighting requires a dimmable control to enable energy savings and fulfil a growing consumer demand. In this paper, the dimmable single-stage power factor correction (PFC) continuous conduction mode (CCM) flyback converter that employs no electrolytic capacitor is presented. The LC resonant filter is alternatively applied to reduce the 120[Hz] ripple on the output. And the optimum value of the LC resonant filter parameters considering both efficient and performance is analysed. Simulation and experimental results verify the satisfactory operation of the converter.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.319-320
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• 2013

본 논문에서는 PSR(Primary Side Regulator)에 적용 가능한 새로운 방식의 부하 전류 예측 알고리즘을 제안한다. 기존의 부하 전류 예측 방식은 DCM(Discontinuous Conduction Mode) 및 BCM(Boundary Conduction Mode) 동작만이 가능하다. 하지만 제안된 방식은 Power Balance Rule을 적용한 간단한 알고리즘을 통해 CCM(Continuous Conduction Mode) 동작에서도 정확한 부하 전류 예측이 가능하다. 따라서 높은 출력을 요구하는 어플리케이션에서 고효율 달성에 유리하고, CC(Constant Current) 제어가 우수하다. 제안 알고리즘의 우수성과 신뢰성 검증을 위하여 12W급 플라이백 컨버터의 시작품을 제작하였고, 이를 이용한 실험 결과를 바탕으로 타당성을 확인한다.

• KIPE Magazine
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• v.14 no.1
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• pp.34-39
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• 2009

2001년 1세대 SiC 쇼트키 다이오드의 상용화는 고압 다이오드의 Zero 스위칭손실를 가능하게 하여 기존의 CCM(continuous-current mode) PFC의 효율한계를 극복 시킬수 있었다. 2005년 서지전류와 애벌런치 내량을 향상시킨 2세대 SiC 쇼트키 다이오드는 적용의 범용성을 확대 시켰다. 2009년 전력내량이 증대된 3세대 다이오드는 이상적인 다이오드의 현실화를 위해 한발 더 나아가게 하고 있다. 본고에서는 이러한 노력을 경주해온 인피니언의 SiC 전력반도체 소자의 기술 및 개발 현황을 소개한다.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.12
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• pp.1152-1159
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• 2015

Switching power supply systems are widely used in many industrial fields. Power factor correction (PFC) circuits have a tendency to be applied in new power supply designs. The PFC circuit with a boost converter using an input power source is studied in this paper. In a boost PFC circuit, there are two feedback control loops: a current feedback loop and a voltage feedback loop. In this paper, the regulation performance gained by using the output voltage and compensator to improve the transient response presented at the continuous conduction mode (CCM) of the boost PFC circuit is analyzed. The validity of the designed boost PFC circuit is confirmed by both MATLAB simulation and experimental results.

• Journal of Power Electronics
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• v.17 no.4
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• pp.884-891
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• 2017

The improved transfer functions of the modified Sheppard-Taylor (MS-T) converter, which is capable of regulating output voltage under a wide range of input voltage and load variations, negligible current ripple, and fewer components in comparison to the Sheppard-Taylor (S-T) converter, operating in continuous conduction mode (CCM) are investigated in this study. Its DC equilibrium point, small signal model, and transfer functions are derived and analyzed. Then, the voltage controller is applied for this MS-T converter. The comparisons between the derived model and the existing model are presented. The hardware circuit is designed and the circuit experiments are provided for validation. The results show that the improved transfer functions of the MS-T converter are more effective and general than the previous ones for describing its real characteristics.

• Journal of Electrical Engineering and Technology
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• v.12 no.3
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• pp.1082-1089
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• 2017

Negative output elementary super lift Luo converter (NOESLLC), which has the significant advantages including high-voltage transfer gain, high efficiency, high power density, and reduced output voltage/inductor current ripples when compared to the traditional DC-DC converters, is an attractive DC-DC converter for the field of negative DC voltage applications. In this study, in consideration of the voltage across the energy transferring capacitor changing abruptly at the beginning of each switching cycle, the improved averaged model of the NOESLLC operating in continuous conduction mode (CCM) is established. The improved DC model and transfer functions of the system are derived and analyzed. The current mode control is applied for this NOESLLC. The results from the theoretical calculations, the PSIM simulations and the circuit experiments show that the improved DC model and transfer functions here are more effective than the existed ones of the NOESLLC to describe its real dynamical behaviors.

• The Transactions of the Korean Institute of Power Electronics
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• v.17 no.3
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• pp.259-265
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• 2012

This paper introduces a method for design and implementation of a current controller for boost converter operating in continuous conduction mode (CCM) using a digital signal processor (DSP). A Proportional-Integral (PI) type current controller outputs an average voltage command for inductor, used in the input side of the boost converter, and the duty-ratio of PWM (pulse width modulation) signal for switching device is directly calculated from the average voltage command. The gains of the PI current controller are selected such that the current response characteristics are the same as those of a first-order low-pass filter. The proposed current control scheme is implemented using a DSP based on fixed-point math operations and an experimental study has been performed to validate the proposed method.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.2
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• pp.89-96
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• 2015

This paper presents a high efficiency, PSM/DCM/CCM triple mode boost DC-DC converter for mobile application. This device operates at Pulse-Skipping Mode(PSM) when it enters light load, and otherwise operate the operating frequency of 1.4MHz with Pulse-Width Modulation(PWM) mode. Especially in order to improve the efficiency during the Discontinuous-Conduction Mode(DCM) operation period, the reverse current prevention circuit and oscillations caused by the inductor and the parasitic capacitor to prevent the Ringing killer circuit is added. The input voltage of the boost converter ranges from 2.5V ~ 4.2V and it generates the output of 4.8V. The measurement results show that the boost converter provides a peak efficiency of 92% on CCM and 87% on DCM. And an efficiency-improving PWM operation raises the efficiency drop because of transition from PWM to PFM. The converter has been fabricated with a 0.18um Dongbu BCDMOS technology.