• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.610-614
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• 2004

Recently, an active-clamp, full-bridge boost converter has been actively studied for high-power applications such as power factor correction and battery discharger. However, DC and AC modeling for this converter has not conquered. In this paper, a DC and small-signal AC modeling for the active-clamp, full-bridge boost converter is described. Based on the operation principle, the ac part of the converter can be replaced by a do 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.

• The Transactions of the Korean Institute of Power Electronics
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• v.22 no.4
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• pp.360-368
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• 2017

This paper proposes the 80-kW high-efficiency bidirectional hybrid SiC boost/buck converter using droop control for DC nano-grid. The proposed converter consists of four 20-kW modules to achieve fault tolerance, ease of thermal management, and reduced component stress. Each module is constructed as a cascaded structure of the two basic bi-directional converters, namely, interleaved boost and buck converters. A six-pack hybrid SiC intelligent power module (IPM) suitable for the proposed cascaded structure is adopted for high-efficiency and compactness. The proposed converter with hybrid switching method reduces the switching loss by minimizing switching of insulated gate bipolar transistor (IGBT). Each module control achieves smooth transfer from buck to boost operation and vice versa, since current controller switchover is not necessary. Furthermore, the proposed parallel control using DC droop with secondary control, enhances the current sharing accuracy while well regulating the DC bus voltage. A 20-kW prototype of the proposed converter has been developed and verified with experiments and indicates a 99.3% maximum efficiency and 98.8% rated efficiency.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.5
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• pp.889-896
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• 2020

In general, there are various types of boost converters such as Boost converters, Buck-Boost converters, Flyback converters, Push-Pull converters, etc. Among them, Boost converters are the most widely used and step up converters in a very simple form. However, Boost converter has DCM mode operation, big ripple problem and RHPZ problem. In order to solve these problems, a converter to which the new topology was applied was presented, but among them, the KY converter improved the Boost converter's DCM mode operation, the big ripple problem and the RHPZ problem. However, the conventional KY converter has a drawback that the voltage gain is relatively lower than that of the Boost converter. Therefore, in this paper, we proposed a new KY converter that solves the problem of low voltage gain while having the advantages of the conventional KY converter.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.4
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• pp.224-230
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• 2006

The conventional way to implement a bidirectional converter with boost/buck has been to use two general purpose PWM ICs with a single supply voltage. In this case, when one direction mode is in operation, the other is disabled and the output of the error amplifier of the disabled IC may be saturated to a maximum value or zero. Therefore, during mode transition, a circuit which can disable the switching operation for a certain time interval is required making it impossible to get a seamless transition. In this paper, the limitations of the conventional 42V/14V bi-directional DC/DC converter implemented with general current mode PWM ICs with a single supply voltage are reviewed and a new current mode PWM controller circuit with a dual voltage system is proposed. The validity of the proposed circuit is investigated through simulation. and experiments.

• 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.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.2
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• pp.98-104
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• 2012

This paper presents a novel transformer isolated parallel connected full-bridge dc-dc converter using recently developed trans-Z-source network. Unlike the traditional voltage -fed or current-fed converters, the proposed converter can be open- and short-circuited without damaging switching devices. Therefore, the desired buck and boost function can be achieved and the converter reliability can be greatly improved. A 6 kW prototype dc-dc converter is built and tested to verify performances of the proposed converter.

• Journal of Power Electronics
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• v.18 no.3
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• pp.879-891
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• 2018

A bidirectional dc-dc converter is used in battery energy storage systems owing to the growing requirements of a charging and discharging mode of battery. The magnetic coupling of output or input inductors in parallel-connected multi modules of a bidirectional dc-dc converter is often utilized to reduce the peak-to-peak ripple size of the inductor current. This study proposes a novel design guideline to achieve minimal ripple size of the inductor current under bidirectional power flow. The newly proposed design guideline of optimized coupling factor is applicable to the buck and boost operation modes of a bidirectional dc-dc converter. Therefore, the coupling factor value of the coupled inductor does not have to be optimized separately for buck and boost operation modes. This new observation is explained using the theoretical model of coupled inductor and confirmed through simulation and experimental test.

• Proceedings of the KIPE Conference
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• 2010.11a
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• pp.173-174
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• 2010

In this paper, authors propose a new buck-boost converter of discontinuous conduction mode (DCM) added electric isolation. The proposed converter with DCM eliminates the complicated circuit control requirement and reduces the size of components. The general converters of high efficiency are made that the power loss of the used switching devices is minimized. To achieve the soft switching operation of the used control switches, the proposed converter uses a lossless snubber capacitor. The proposed converter achieves the soft-switching for all switching devices without increasing their voltage and current stresses. The result is that the switching loss is very low and the efficiency of converter is high. The soft switching operation of the proposed converter is verified by digital simulation and experimental results.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.151-154
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• 1988

Quantum converters, a subset of resonant converters operating with optimal conditions are modeled. It is shown that series resonant converter(SRC) can be modeled as buck/boost converter with an equivalent inductor and parallel resonant converter(PRC) can be modeled as Cuk converter, with an equivalent capacitor. Also new resonant circuits with boost, buck-boost and Cuk converter characteristics are proposed. From these models, the quantum converters can be designed to be controlled with closed loop feedback, having many advantages such as low device switching stress, reliable high frequency operation and low EMI.

• Proceedings of the KIEE Conference
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• summer
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• pp.1498-1500
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• 2004

A novel technique for efficiently extracting maximum power from PV panels is proposed, consisting of a modified buck-boost converter, witch is controlled by a DSP. A variation of the proposed MPPT technique is directly use the modified buck-boost converter current reference as a control parameter. Also 4 parallel boost converters have division of load. A theoretical analysis of the proposed converter is performed and compared with experimental results obtained from a 1k[W] prototype solar panel under a controlled experimental setup.