• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.4
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• pp.330-337
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• 1998

A duty cycle average model is mathematically developed for an average model of buck converter employing hysteresis c control. The derived model is able to simultaneously deal with both the continuous conduction mode (CCM) and the d discontinuous conduction mode (DCM) in the time domain. Also. taking advantage of the MAST language of SABER. a t template of the proposed duty cycle average model is built for the time and frequency domain analyses. The accuracy of t this template is verified through the computer simulations.

• Journal of Power Electronics
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• v.16 no.5
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• pp.1861-1868
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• 2016

In this paper, a three-phase AC-DC high step-up converter is developed for application to microscale wind-power generation systems. Such an AC-DC boost converter prossessess the property of the single-switch high step-up DC-DC structure. For power factor correction, the advanced half-stage converter is operated under the discontinuous conduction mode (DCM). Simulatanously, to achieve a high step-up voltage gain, the back half-stage functions in the continuous conduction mode (CCM). A high voltage gain can be obtained by use of an output-capacitor mass and a coupled inductor. Compared to the output voltage, the voltage stress is decreased on the switch. To lessen the conducting losses, a low rated voltage and small conductive resistance MOSFETs are adopted. In addition, the coupled inductor retrieves the leakage-inductor energy. The operation principle and steady-state behavior are analyzed, and a prototype hardware circuit is realized to verify the performance of the proposed converter.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.261-263
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• 2018

본 논문에서는 다수의 고주파 단상 변압기를 사용하여 다수의 독립된 직류 전압원을 만들 수 있는, 여러 다이오드 정류기와 연결된 풀 브릿지 DC-DC 컨버터에 대한 분석 및 제어 기법을 제안한다. 본 토폴로지의 경우 제어 대상인 2차단 직류단이 다수이지만 1차단 스위칭 회로가 하나의 풀 브릿지 회로이기 때문에 2차단 전압의 개별 제어를 위한 자유도가 부족하다. 이에 따라 다수 직류단 전압의 평균 값을 제어하는 방식이 사용된다. 이때, 각 직류단에 다른 용량의 부하가 연결되어 있는 상황에 대하여 상세한 분석이 필요하다. 본 논문에서는 제시된 토폴로지(Topology)를 하드 스위칭 기반의 DCM(Discontinuous Conduction Mode) 및 CCM(Continuous Conduction Mode) 동작의 경우에 대해 분석한다. 이를 바탕으로, 직류단 전압 제어를 위한 전향 보상 및 안티 와인드업을 포함하는 Integral and Proportional (IP) 제어기를 구성하고, 제어기 이득 및 전향 보상을 수식화 한다. 최종적으로 구해지는 제어기의 전달 함수를 통해, 제어기가 정확하게 설계되었는지 컴퓨터 시뮬레이션으로 검증한다.

• 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.

• Journal of Power Electronics
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• v.15 no.2
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• pp.356-365
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• 2015

This paper presents a new single phase front-end ac-dc bridgeless power factor correction (PFC) rectifier topology. The proposed converter achieves a high efficiency over a wide range of input and output voltages, a high power factor, low line current harmonics and both step up and step down voltage conversions. This topology is based on a non-inverting buck-boost (Zeta) converter. In this approach, the input diode bridge is removed and a maximum of one diode conducts in a complete switching period. This reduces the conduction losses and the thermal stresses on the switches when compare to existing PFC topologies. Inherent power factor correction is achieved by operating the converter in the discontinuous conduction mode (DCM) which leads to a simplified control circuit. The characteristics of the proposed design, principles of operation, steady state operation analysis, and control structure are described in this paper. An experimental prototype has been built to demonstrate the feasibility of the new converter. Simulation and experimental results are provided to verify the improved power quality at the AC mains and the lower conduction losses of the converter.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.11B no.3
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• pp.104-111
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• 2001

The design procedures and experimental results of a single-stage electronic ballast using half-bridge resonant inverter are presented in this paper. The proposed topology is based on a single-stage ballast which combines a boost converter and a half-bradge series resonant inverter. High power factor is achieved by using the boost semi-stage operating in discontinuous conduction mode and inverter semi-stage operated above resonant frequency to provide zero voltage switching is empolyed to ballast the fluorescent lamp Experimental results from the ballast system with 36W fluorescent

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.91-92
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• 2011

단방향 DC-DC컨버터는 불연속 전도모드(Discontinuous Conduction Mode:DCM)구간에서 전류기준치와 실제 흐르는 평균전류와의 오차가 존재하여 MPPT추종이 어렵거나 불가하다. 따라서 본 논문은 전류제어를 하는데 전류오차율을 2%까지 최소화할 수 있는 전류게인 전향보상기법을 이용하여 DCM 구간에서도 98%이상의 MPPT효율로 MPPT수행이 가능함을 실험으로 증명하였다.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.327-332
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• 1999

In this paper, six harmonic injection PWM method for reducing total harmonic distortion in single switch three phase discontinuous conduction mode boost converter is presented. In the proposed method, periodic six harmonic voltage is injected in the control circuit to vary the duty ratio of the converter switch within a line cycle so that the fifth order harmonic of the input current is reduced. Experimental results are verified by converter operating at 400V/6kW with three phase 140V~220V input.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.626-630
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• 1999

A new integrated single-stage zero current switched(ZCS) quasi-resonant converter (QRC) for the power factor correction(PFC) converter is introduced in this paper. The power factor correction can be achieved by the discontinuous conduction mode(DCM) operation of an input current. The proposed converter has the characteristics of the good power factor, low line current harmonics, and tight output regulation. Furthermore, the ringing effect due to the output capacitance of the main switch can be eliminated by use of active clamp circuit.

• Journal of Satellite, Information and Communications
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• v.9 no.3
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• pp.86-90
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• 2014

A DC-DC Converter operates in CCM(Continuous Coundcution Mode), DCM(Discontinuous Conduction Mode), CRM(Critical Conduction Mode). The CRM is boundary between CCM and DCM. If a DC-DC converter is designed to operate in CRM, its inductor volume can decrease and power loss which caused by switch and diode can decrease. In this paper, the DC-DC converter which operates in CRM is applied to a solar array regulator(SAR) for the satellite. The switching frequency of the CRM boost SAR changes according to input and output condition. The switching frequency limit logic is applied to limit the maximum switching frequency. Meanwhile, the small signal transfer function of the CRM boost SAR is simple, so the controller design is also simple. In this paper, the small signal transfer function from control reference to solar array voltage is induced. And the voltage controller is designed based on the small signal transfer function. Finally, the CRM boost SAR is verified by simulation.