• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.337-338
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• 2013

Combination the several type of single phase power conversion utilized simply topology are proposed in this paper. Totally four kind of converter are investigated, they are Boost AC/AC Converter, Buck AC/AC Converter, Boost AC/DC Converter, and Buck DC/AC Converter. Two types action mode are presented to determine the functional of circuit. First is AC chopper action mode, representation of the AC/AC converter. AC chopper action mode offered the sinusoidal current waveform, better power factor, faster dynamics, and smaller input/output filter. They present high robustness, offer safe commutation and have high efficiency. The second is full bridge action mode, determined the transformation AC to DC power and otherwise. Four switching devices and one magnetic contactor will establish the mode operation of circuit and manage the flow of power proceed in proper. The correction and advance of the kind of converter are verified by simulation.

• IEIE Transactions on Smart Processing and Computing
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• v.4 no.5
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• pp.371-378
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• 2015

In this paper, a different type of pulse width modulation (PWM) control scheme for a buck converter is introduced. The proposed buck converter uses PWM with frequency hopping and a low quiescent.current low dropout (LDO) voltage regulator with a power supply rejection ratio enhancer to reduce high spurs, harmonics and output voltage ripples. The low quiescent.current LDO voltage regulator is not described in this paper. A three-bit binary-to-thermometer decoder scheme and voltage ripple controller (VRC) is implemented to achieve low voltage ripple less than 3mV to increase the efficiency of the buck converter. An internal clock that is synchronized to the internal switching frequency is used to set the hopping rate. A center frequency of 2.5MHz was chosen because of the bluetooth low energy (BLE) application. This proposed DC-DC buck converter is available for low-current noise-sensitive loads such as BLE and radio frequency loads in portable communications devices. Thus, a high-efficiency and low-voltage ripple is required. This results in a less than 2% drop in the regulator's efficiency, and a less than 3mV voltage ripple, with -26 dBm peak spur reduction operating in the buck converter.

• Proceedings of the IEEK Conference
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• 2002.06e
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• pp.207-210
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• 2002

This paper describes a design of multiple-mode single-output DC/DC converter which can be used in both up and down conversion. Proposed up/down converter does not produce a negative voltage which is generated in conventional buck-boost type converter. Three types of operation mode(up/down/bypass) are controlled by the input voltage sense and command signals of target output voltage. PFM(pulse frequency modulation) control is adopted and modified for fast tracking and for precise output voltage level with an aid of output voltage sense. Designed DC/DC converter has the performance of less than 5 % ripple and higher than 80 % efficiency. Chip area is 3.50 mm ${\times}$ 2.05 mm with standard 0.35 $\mu\textrm{m}$ CMOS technology.

• Journal of the Korean Institute of Telematics and Electronics
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• v.20 no.4
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• pp.41-46
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• 1983

The current-fed DC-DC converter has only one energy storage reactor in series with the input for any number of outputs and is insensitive to transformer volt-second unbalance. It is considered that these properties of the converter are considerable advantages over other maltiple-output circuits. The steady-state and dynamic characteristic and stability for the current-fed DC-DC con-verter are analyzed in detail. The analysis is carried out by the state-space averaging method for the operation with the duty ratio less than 50% and is confirmed by the experiment. From the evaluation of stability it is identified that the stability of this converter is excellent as compared with that of the conventional buck type converter.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1116-1117
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• 2007

In this paper, the control method of maximum power point tracking (MPPT) using the duty ratio control of buck-type dc/dc converter is presented for seaflow generation system. The advantage of the proposed MPPT method is that characteristics of seaflow generator(SG) with respect to seaflow speed, required in the conventional MPPT method, are not needed. Also, due to using the SG output power as a control parameter, neither characteristics of the seaflow speed nor measurements of the rotational speed of the generator are required. Thus, there are advantages that seaflow generation system having features of lower cost and complexity, and higher reliability can be designed. In this paper, Seaflow generation system using the buck-type dc/dc converter is proposed and the effectiveness of the MPPT algorithm is confirmed by matlab simulink.

• Transactions of the Korean hydrogen and new energy society
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• v.19 no.5
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• pp.417-422
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• 2008

In this paper, a novel DC/DC low-voltage high-current converter circuit is proposed to improve the efficiency of power converter used in the grid-connected fuel-cell generator system. We proposed a novel high efficiency grid-connected power conditioning system for RPG fuel cell. On the result of that, the loss of system was decreased rapidly by driving stack within the condition of maximum efficiency. The peak currents of the current-type inductor and the transformer's coil are reduced by synchronizing switching frequency of Buck-type converter is increased twice as the Push-Pull converter's switching frequency. The novel structure of DC/DC converter is able to realize ZVS-ZCS in fuel-cell system is proposed. The proposed switching component of Push-Pull converter has the ZVS and ZCS function by using the circuit of new passive clamp.

• Journal of Power Electronics
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• v.9 no.6
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• pp.835-844
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• 2009

In this paper a new buck-boost type DC-DC converter is presented. Its voltage gain is positive, all active elements operate under soft-switching condition independent of loading, magnetic isolation and self output short-circuit protection exist, and very fast dynamic operation is achievable by a simple bang-bang controller. This converter also exhibits appropriate PFC characteristics since its input current is inherently proportional to the source voltage. When the voltage source is off-line, it is sufficient to add an inductor after the rectifier, then near unity power factor is achievable. All essential guidelines to design the converter as a DC-DC and a PFC regulator are presented. Simulation and experimental results verify the developed theoretical analysis.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.89-92
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• 2003

Recently, Research that output voltage control using several control methods to dc-dc converter that is non-linear system is gone. This paper describes control algorithm of the Buck type DC-DC converter using neural network controller We conform a rightness theoretical analysis by comparing a theoretical values, simulation values obtained from simulation tool and experimental values obtained from experiment. the neural network controller got better special characteristic than the hysteresis controller, This paper is thought to be applied to several power conversion system use neural network controller.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.3
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• pp.54-59
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• 1985

From the foregoing papers, it has been clarified that the push-pull current-fed DC-DC converter is excellent in stability as compared with the other conventional DC-DC con-verters. The relation between the stability of the converter and the capacitance of smoothing condenser is analyzed, considering the ESR of smoothing condenser and the 1 st order phase lag of the feedback circuit. From the results, it is known that when the capacitance of smoothing condenser is reduced, the stability of the converter is also excellent as compared with the conventional buck type converter, whereas there are limitations for practical use, since the ripple of output voltage increases by increasing of output current.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.2
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• pp.111-117
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• 1990

This paper investigated the effect of the zero on the right-half-plane on stability in the buck-boost DC-DC converter which is one type of the switching regulator, and the stability region in connection with the output current was shown by evaluating the feed-back gain. From the result it is shown that the stability decreases by the existence of the zero on the right-half-plane. We carried out a compensation by a pole in the feedback circuit and obtained the available stability region in relation to the gain band-width product. These results proved to be the validity by experiment.