• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.11
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• pp.540-546
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• 2005

This paper presents a boost circuit topology driving in high - frequency It solves the problem which arised from hard-switching in high-frequency using a period of resonant circuit and operating under the principle of ZCS turn-on and ZCZVS turn-off commutation schemes. In the existing circuit, it has the high voltage and current stress in free- wheeling diode. But in the proposed circuit, it has voltage and current stress which is lower than voltage and current stress of existing circuit with modifing a location of free-wheeling diode. In this paper, it explained the circuit operation of each mode and the waveform of each mode. Also the experiment results compare the voltage and current stress of free-wheeling diode in the existing circuit with the voltage and current stress of that in the proposed circuit. Moreover, it compares and analyzes the proposed circuit's efficiency with the existing circuit's efficiency according to the change of load current.

• 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

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.3
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• pp.278-283
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• 1997

The rectifier is the main element in the telecom DC power system. This paper investigates the advantages and disadvantages of three rectifier techniques ; thyristor, ferro - resonant, and switched - mode. Compared with other techniques, the switched - mode rectifier tech¬nique offers several advantages such as higher efficiency, smaller size and weight, and lower audible noise. Technical requirements in telecom rectifier plant are also described. Finally, the future trends in telecom powering are discussed in connection with the advance oftelecom net¬works.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1165-1167
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• 2000

This paper describes a current fed high frequency resonant inverter used as the power supply for sealing-wax. The proposed inverter can reduce switching losses, noise and voltage stress at turn-on and turn-off. The analysis of proposed circuit uses normalized parameter and characteristic estimation which is needed in each step before design is generally described according to normalized frequency ($\mu$), coefficient of coupling($\kappa$) and all parameters. The theoretical analysis is proved through experiment and this circuit shows that it can be used practically as the power supply system for sealing wax and DC-DC converter.

• Aerospace Engineering and Technology
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• v.6 no.1
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• pp.109-113
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• 2007

In this paper, the design process of the High Voltage Power Supply for RLG(Ring Laser Gyroscope) is described. The specification for High Voltage Power Supply(HVPS) is proposed. Also, The analysis of Flyback converter topology is explained. The Design for the HVPS is composed of the inverter circuit, feedback control circuit, high frequency switching transformer design, and voltage doubler circuit.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.2
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• pp.54-63
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• 2007

Recently, a fuel cell with low voltage and high current output characteristics is remarkable for new generation system. It needs both a DC-DC step-up converter and DC-AC inverter to be used in fuel cell generation system. Therefor, this paper, consists of an isolated DC-DC converter to boost the fuel cell voltage $380[V_{DC}]$ and a PWM inverter with LC filter to convent the DC voltage to single-phase $220[V_{AC}]$. Expressly, a tapped inductor filter with freewheeling diode is newly implemented in the output filter of the proposed high frequency isolated ZVZCS PWM DC-DC converter to suppress circulating current under the wide output voltage regulation range, thus to eliminate the switching and transformer turn-on/off over-short voltage or transient phenomena. Besides the efficiency of 93-97[%]is obtained over the wide output voltage regulation ranges and load variations.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.6
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• pp.16-24
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• 2009

In this paper, DC-DC buck converter with on-chip filter inductor and capacitor is presented. By operating at high switching frequency of 50MHz with stacked interleaved topology, we reduced inductor and capacitor sizes compared to previously published DC-DC buck converters. The proposed circuit is designed in a standard $0.5{\mu}m$ CMOS process, and chip area is $9mm^2$. This circuit operated at the input voltage of $3{\sim}5V$ range, the maximum load current of 250mA, and the maximum efficiency of 71%.

• Journal of Electrical Engineering and Technology
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• v.10 no.1
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• pp.271-279
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• 2015

Induction cooking application with multiple loads need high power inverters and appropriate control techniques. This paper proposes an inverter configuration with buck-boost converter for multiple load induction cooking application with independent control of each load. It uses one half-bridge for each load. For a given dc supply of $V_{DC}$, one more $V_{DC}$ is derived using buck-boost converter giving $2V_{DC}$ as the input to each half-bridge inverter. Series resonant loads are connected between the centre point of $2V_{DC}$ and each half-bridge. The output voltage across each load is like that of a full-bridge inverter. In the proposed configuration, half of the output power is supplied to each load directly from the source and remaining half of the output power is supplied to each load through buck-boost converter. With buck-boost converter, each half-bridge inverter output power is increased to a full-bridge inverter output power level. Each half-bridge is operated with constant and same switching frequency with asymmetrical duty cycle (ADC) control technique. By ADC, output power of each load is independently controlled. This configuration also offers reduced component count. The proposed inverter configuration is simulated and experimentally verified with two loads. Simulation and experimental results are in good agreement. This configuration can be extended to multiple loads.

• Transactions on Electrical and Electronic Materials
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• v.14 no.5
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• pp.235-241
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• 2013

A low power CMOS control circuit is applied in an integrated DC-DC buck converter. The integrated converter is composed of a feedback control circuit and power block with 0.35 ${\mu}m$ CMOS process. A current-sensing circuit is integrated with the sense-FET method in the control circuit. In the current-sensing circuit, a current-mirror is used for a voltage follower in order to reduce power consumption with a smaller chip-size. The N-channel MOS acts as a switching device in the current-sensing circuit where the sensing FET is in parallel with the power MOSFET. The amplifier and comparator are designed to obtain a high gain and a fast transient time. The converter offers well-controlled output and accurately sensed inductor current. Simulation work shows that the current-sensing circuit is operated with an accuracy of higher than 90% and the transient time of the error amplifier is controlled within $75{\mu}sec$. The sensing current is in the range of a few hundred ${\mu}A$ at a frequency of 0.6~2 MHz and an input voltage of 3~5 V. The output voltage is obtained as expected with the ripple ratio within 1%.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.4
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• pp.35-45
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• 2008

This paper present the Three-Level converter using IM(Integrated Magnetics) method for high power application. In power conversion system, magnetic components are important devices used for energy storage, energy transfer, galvanic isolation and filtering. The proposed Three-Level converter is to reduce the number of magnetic components using transformer integrated with output inductor. This paper proposes reluctance model base on the magnetic analysis for the Three-Level converter. Also, the secondary rectification was discussed by a single core transformer winding. A protype featuring 540[V] input, 48[V] output, 40[kHz] switching frequency, and 3[kW] output power using IGBT.