• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.5B
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• pp.974-984
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• 2000

A CMOS voltage driver circuit for voltage down converter is proposed. An adaptive biasing technique is used to enhance load regulation characteristics. The proposed driver circuit uses the NMOS transistor as a driving transistor, so it does not suffer from large Miller capacitances which is one of the problems with conventional PMOS driving transistor, and hence achieves good phase margin and stable frequency response. No additional complex circuit for frequency compensation such as compensation capacitor is required in this implementation. For the same current capability, the size of NMOS transistor in driver circuit is smaller than that of PMOS counterpart. So the smaller die area can be achieved. The circuits is implemented using a 0.8 ${\mu}{\textrm}{m}$ CMOS process and has a die area of 150 ${\mu}{\textrm}{m}$ x 360 ${\mu}{\textrm}{m}$. Proposed circuit has a quiescent power of 60 . In the current driving range from 100 $mutextrm{A}$ to 50 ㎃, load regulation of 5.6 ㎷ is measured.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.5
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• pp.352-357
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• 2000

This paper presents about an example of circuit design and characteristics of inverter according to the variable capacitance of the DC voltage source separation capacitor used in ZVS-HB type high frequency resonant inverter. The soft switching technology known as ZVS is used to reduce turn off loss at switching. In the event the capacitance of the DC voltage source separation capacitor is varied, the analysis of inverter circuit has generally described by using normalized parameter and operating characteristics have been evaluated in terms of switching frequency and parameters. According to the calculated characteristics value, a method of the circuit designs and operating characteristic of the inverter is also presented in this paper. In addition, this paper proves the validity of theoretical analysis through the experiment. This proposed inverter shows that it can be practically used in future as power source system for the lighting equipment of discharge lamp, DC-DC converter etc.

• 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.

• Proceedings of the KIEE Conference
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• 2006.04a
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• pp.213-215
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• 2006

A static frequency converter(SFC) in a pumped storage power plant is important equipment for converting electric motor kinetic energy into electric Bower. A SFC monitoring system consists of high voltage thyristor firing equipment, fault detection module, data gathering module, real time data processing equipment and man machine Interface system. This paper describes SFC system overview, developed SFC monitoring system configuration including system characteristics. and successful application result to San-Cheong pumped storage power plant.

• Journal of Power Electronics
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• v.14 no.4
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• pp.632-640
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• 2014

For low-power high-frequency LED driver applications in small form factor mobile products, a high-efficiency boundary conduction mode tapped-inductor boost converter is proposed. In the proposed converter, the switch and the diode achieve soft-switching, the diode reverse-recovery is alleviated, and the switching frequency is very insensitive to output voltage variations. The circuit is quantitatively characterized, and the design guidelines are presented. Experimental results from an LED backlight driver prototype for a 14 inch notebook computer are also presented.

• The Transactions of the Korean Institute of Power Electronics
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• v.22 no.3
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• pp.263-269
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• 2017

This paper proposes a novel circulating current control method for an MMC-HVDC system based on Vector PI control. The method can suppress second-order harmonics of the circulating currents under balanced and unbalanced grid conditions. The proposed method is robust to grid frequency variation. The effectiveness of the proposed method is verified through frequency response and time domain simulation.

• ETRI Journal
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• v.33 no.3
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• pp.366-373
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• 2011

In this paper, we propose a low-power all-digital phase-locked loop (ADPLL) with a wide input range and a high resolution time-to-digital converter (TDC). The resolution of the proposed TDC is improved by using a phase-interpolator and the time amplifier. The phase noise of the proposed ADPLL is improved by using a fine resolution digitally controlled oscillator (DCO) with an active inductor. In order to control the frequency of the DCO, the transconductance of the active inductor is tuned digitally. The die area of the ADPLL is 0.8 $mm^2$ using 0.13 ${\mu}m$ CMOS technology. The frequency resolution of the TDC is 1 ps. The DCO tuning range is 58% at 2.4 GHz and the effective DCO frequency resolution is 0.14 kHz. The phase noise of the ADPLL output at 2.4 GHz is -120.5 dBc/Hz with a 1 MHz offset. The total power consumption of the ADPLL is 12 mW from a 1.2 V supply voltage.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.2
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• pp.104-111
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• 1997

In this paper, three-phase PWM AC to DC boost converter that operates with unity power factor and sinusodial input line currents is presented. The current control of this converter is based on the space vector PWM strategy with fixed switching frequency and the line currents track to reference currents within one sampling time interval. By using this control strategy low ripples in the outut current and the voltage as well as fast dynamic response are achieved with small dc link cpacitance employed.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.85-90
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• 1998

A parallel-resonant converter with zero-voltage-switching, pulse-width-modulation(ZVS-PWM) control is proposed. Similar to the previously proposed series-resonant counterpart, it has a simple structure and can be controlled at a constant switching frequency using an active-clamp technique. The nearly constant current output characteristic of the parallel-resonant converter lends itself beneficially to precisely controlled constant current power supply applications. An experimental breadboard featured an accuracy of $\pm$1% for an output current of 2A, with an efficiency of 75%.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.519-524
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• 2002

This paper presents a soft-switching technique of single-stage power conversion Matrix Converter of AC-AC converters. Conventional hard-switching method is limited to operate at low switching frequency due to increased switching loss. In this paper, by additional auxiliary switch circuits, it is shown that the main switch of the matrix converter operate as a zero-voltage switches, and the auxiliary switch operate as a zero current switch. Finally, the soft-switching technique with auxiliary switches is compared with conventional hard-switching technique, and Is analyzed by simulation.