• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.2
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• pp.169-176
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• 2005

In this paper, a DC and small-signal AC modeling for the active-clamp, ful1-bridge boost converter is described. Based on the operation principle, the ac part of the converter can be replaced by a dc counterpart. Then, a conceptual equivalent circuit is derived by rearranging the switches. The equivalent circuit for this converter consists of CCM(Continuous conduction mode) boost and DCM(Discontinuous conduction mode) buck converter. The analyses for the equivalent CCM boost and DCM buck converter are done using the model of PWM switch. The theoretical modeling results are confirmed through experiment or SIMPLIS simulation.

• Journal of Power Electronics
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• v.2 no.2
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• pp.139-145
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• 2002

Because conventional switching converters have been usually using unbalanced circuit topologies, parasitice between the drain/collertor of an active switch and frame ground through its heat sink may generate the commom-mode conducted noise. We have proposed a balanced switching converter circuit, whitch is an effective way to reduce the commom-mode converter version of the balanced switching converter was presented and the mechanism of the commom-mode noise reduction was explained using equivalent circuits. This paper extends the concept of the balanced switch converter circuit and presents a buck-boost converter version of the blanced switching converter. The feature of common-mode niose reduction is confirmed by experimental resuits and the mechanisem of the commom-mode niose reduction is explained using equivalent circuits.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.2
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• pp.86-90
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• 2001

This paper presents a multi output converter system that controls, simultaneously, the separate buck converter and boost converter with the different specification by one digital controller using fuzzy algorithm. As two separate converters are regulated by only one DSP, it is possible to achieve the simple digital control circuit for regulating multi output DC-DC converter. Inference procedure of fuzzy controller is included. The control characteristics of each PWM DC-DC converter is validated by experimental results.

• Journal of Power Electronics
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• v.14 no.4
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• pp.641-648
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• 2014

This paper presents the design considerations and analysis for an interleaved boundary conduction mode power factor correction buck converter. A thorough analysis of the harmonic content of the AC line current is presented to examine the allowable voltage gain (K value) for meeting the EN61000-3-2, Class D standard while maximizing efficiency. The results of the harmonic analysis are used to derive the required value of K and therefore the output voltage necessary to meet the class D requirements for a given AC line voltage. The discussed design consideration and harmonic current analysis are verified on a 300W universal line experimental prototype converter with an 80V output. The measured efficiencies remain above 96% down to 20% of the full load. The input current harmonics also meet the IEC61000-3-2 (class D) standard.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.1
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• pp.1-8
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• 2014

The conventional Three-Stage electronic ballast is stable, but Two-Stage electronic ballast has been researching because of efficiency. Three-Stage electronic ballast is consisted of PFC circuit, buck converter, and inverter circuit, but Two-stage is consisted of PFC circuit, Buck-Inverter full bridge circuit. The Buck-Inverter full bridge inverter consists of two half bridge inverters for low frequency switching, and high frequency switching. In the case of street lamp it is far from a lamp to a ballast, the conventional pulsed high voltage ignitor can not turn on the HID lamps because of reduction of ignition voltage. Therefore, it needs to do the research on a resonant ignition to turn on the HID lamps. Therefore, in the Two-Stage electronic ballast which has the resonant tank for ignition, the transient resonant current because of low frequency changing is analyzed, the novel algorithm is proposed to resuce the transient current.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.2
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• pp.123-130
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• 2007

This paper presents the generalized and explicit expressions for evaluating the performance of the multi-phase interleaved buck converter (IBC) operating in discontinuous inductor current mode (DICM). The full-order averaged model is derived. The generalized transfer functions of interest are presented and the dynamic characteristics are analyzed. The generalized analysis of converter performance is verified through the experimental and simulation results.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.189-190
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• 2015

This paper investigates an economic and highly efficient power converter topology and its modulation scheme for 60kW rapid EV charger system. The target system consists of three-phase three-switch buck-type rectifier topology. A new Carrier Based PWM scheme along with its simple implementation using logic gates is introduced in this paper. This PWM scheme replaces the diode rectifier equivalent switching state with an active switching state producing the effectively same current flowing path. As a result, the distortion of input current during the polarity reversal of capacitor line voltage can be mitigated. The proposed modulation technique is confirmed through simulation verification. The proposed modulation technique and its implementation scheme can expand the operation range of the three-phase three-switch buck-type rectifier having ac input and capacitor ripple current of high quality.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.195-197
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• 1995

In this paper, for a constant switching frequency, the configuration and the control strategy of the resonant buck-boost type converter are proposed by the combination of zero voltage switching(ZVS) and zero current switching(ZCS) with PWM method. Also, in the configuration of power control circuit, transformer is not used in the viewpoint of economy. And the circuit has fewer power switching elements than a general resonant power converter, simulation results and experiments make show the advantages mentioned.

• Proceedings of the KIPE Conference
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• 2016.11a
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• pp.15-16
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• 2016

This paper proposes an isolated DCDC converter that consists of unregulated LLC resonant converter and non-isolated synchronous buck converter for battery charger of energy storage systems application. The unregulated converter operates as transformer with fixed duty ratio and switching frequency. The synchronous buck converter is installed in the output of the LLC resonant converter. And the converter charges and discharges the battery by controlling a current of battery. The proposed converter can get the high efficiency by separating function. This paper explains design of an unregulated converter and synchronous converter.

• Proceedings of the KIPE Conference
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• 2015.11a
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• pp.127-128
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• 2015

소형 전자장비의 증가에 따라 배터리와 배터리 충전기 사용 또한 증가하고 있으며, 이에 따른 충전기의 고효율 확보가 중요해지고 있다. 본 논문에서는 Buck PFC 및 LLC 공진형 컨버터를 기반으로 LLC 공진형 컨버터의 스위칭 주파수 제어 방식과 DC Link 전압 가변 제어 방식의 효율을 비교 분석 한다. 이를 통해 효율적인 배터리 충전을 위한 제어 알고리즘 도출하고 충전 시스템을 설계한다.