• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.9
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• pp.1-7
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• 2010

Ceramic metal halide lamps have been widely used due to long lifetime, high luminous efficiency and good colour rendering. 35[W] ceramic metal halide lamps has very different characteristics between ignition state and steady state. The developed electronic ballast is satisfied to both ignition state and steady state characteristics by using a micro-controller. The proposed electronic ballast is consists of EMI filter, Full-wave rectifier, Active PFC, DBI(Dual Buck Inverter), Igniter and control circuit. It enables to supply both low-frequency rectangular wave voltage and current to the lamp by using DBI(Dual Bcuk Inverter) structure.

• Journal of Power Electronics
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• v.13 no.1
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• pp.40-50
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• 2013

In this paper, a new zero-voltage-switching, high power-factor, bridgeless rectifier is introduced. In this topology, an auxiliary circuit provides soft switching for all of the power semiconductor devices. Thus the switching losses are reduced and the highest efficiency can be achieved. The proposed converter has been analyzed and a design procedure has been introduced. The control circuit for the converter has also been developed. Based on the given approach, a 250 W, 400 Vdc prototype converters has been designed at 100 kHz for universal input voltage (90-264 Vrms) applications. A maximum efficiency of 94.6% and a power factor correction over 0.99 has been achieved. The simulation and experimental results confirm the design procedure and highlight the advantages of the proposed topology.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.368-369
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• 2018

In this paper, a wireless charging system for drones is developed. The system is consists of PFC(Power Factor Correction), Full-Bridge inverter, S-S(Series-Series) resonant circuit and Full-Bridge rectifier. The parameters of the S-S resonant circuit is designed and calculated. According to these parameters and the switching devices, the system model without PFC is setted up with thermal module devices in PSIM. When output voltage is setted to 50[V] and input voltage is changed from 100[V] to 380[V], The efficiency of the system model is measured by simulation.

• KIEE International Transactions on Electrophysics and Applications
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• v.5C no.4
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• pp.152-154
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• 2005

We demonstrate a simple $CO_2$ laser by controlling firing angle of a TRIAC switch in ac power line. The power supply for our laser system switches the voltage of the AC power line (60Hz) directly. The power supply does not need elements such as a rectifier bridge, energy-storage capacitors, or a current-limiting resistor in the discharge circuit. In order to control the laser output power, the pulse repetition rate is adjusted up to 60Hz and the firing angle of TRIAC gate is varied from $45^{circ}$ to $135^{circ}$. A ZCS(Zero Crossing Switch) circuit and a PIC one-chip microprocessor are used to control the gate signal of the TRIAC precisely. The maximum laser output of 40W is obtained at a total pressure of 18 Torr, a pulse repetition rate of 60Hz, and a TRAIC gate firing angle of $90^{circ}$.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1270-1273
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• 2000

A novel zero voltage and zero current switching (ZVZCS) full bridge (FB) PWM converter is proposed. The new converter improves the drawbacks of the previously proposed ZVZCS FB PWM converters [1-5]. A simple auxiliary circuit with neither lossy components nor active switches achieves ZVZCS of the primary switches. Since the proposed converter has many advantages such as simple auxiliary circuit, high efficiency, and low voltage stress of the rectifier diode, it is very attractive for the high power applications. The principles of operation and design considerations are presented. The experimental verifications from 2.5kW prototype converter operating at 70kHz are presented.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1211-1213
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• 2003

A pulse width modulation(PWM) method for single-phase Sepic-type rectifier is introduced in this paper. The characteristics of the proposed PWM system are high performance high power factor with low input current harmonic distortion. The proposed control method is based on the average-current-mode using the dedicated integrated circuit UC3854 this technique it is possible to implement a very simple control circuit for unitary power-factor in CCM operation and also to provide over-current protection.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.477-480
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• 2015

In this paper a low-voltage vibration energy harvesting circuit with MPPT(Maximum Power Point Tracking) control is proposed. By employing bulk-driven technique, the minimum operating voltage of the proposed circuit is as low as 0.8V. The designed MPPT control circuit traces the maximum power point by periodically sampling the open circuit voltage of a full-wave rectifier circuit connected to the piezoelectric device output and delivers the maximum available power to load. The proposed circuit is designed using a $0.35{\mu}m\;CMOS$ process, and the chip area including pads is $1.33mm{\times}1.31mm$. Simulation results show that the maximum power efficiency of the designed circuit is 85.49%.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.1
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• pp.53-57
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• 2010

This study proposes the algorithm which drives the powerless without battery. The exiting wire or RF type dosimeter, which is the computation of the real time with battery on the dose radiation exposure, In the Wired dosimeter, it is trouble to need the maintenance and management by periods. Besides, the case of the RF typed dosimeter with battery, it is requested to size bigger and to replace battery frequently and so on. Especially RF typed dosimeter has trouble to need for the embody with large power consumption on the contactless typed dosimeter. As the method for the low power, the study designed to be down the operating clock of the MPC, to improve the efficiency of the rectifier, to eliminate the external memory and the DC-DC converter for the simplification of the circuit We convince our research contributes not only to understand the simplified circuit and miniaturization, but also to help the design and application technology of the powerless dosimeter.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.6
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• pp.105-112
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• 2003

Diode rectifier which can't be controlled output voltage and phase control converter as AC/DC converter have low power factor and harmonics of lower order in the line current. In this paper, three phase PWM(Pulse Width Modulation) AC/DC boost converter is studied to solve these problems. The characteristics of a proposed converter are to control the phase of current without current sensor as a very simple control algorithm using circuit parameters only and to apply sinusoidal PWM method with fixed switching frequency due to a difficult design of input filter and switching device. We simulate for the proposed algorithm that high power factor is achieved and DC link voltage has fast dynamic response without ripple in rectifying and regenerating operation. As a result of experiment with circuit parameter(inductor, capacitor) decided in simulation, the proposed converter had high power factor and reduction of low order harmonics as against diode rectifier.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.4
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• pp.22-29
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• 2002

Usually, much harmonics are included and cause harmonic loss of motor, torque pulsation, electro-magnetic noise and shock etc. by switching function of inverter when drive induction motor variableness inside. It applied partial resonant Buck converter and three phase voltage type SPWM inverter circuit to induction motor driving system in this paper that see to solve such problem. Changed operation condition variously to do input current of circuit that propose sine-wave by unit power factor almost and capacitor supplied bringing back to life voltage by power supply arranging properly assistance diode and electric power switching. Power factor and efficiency improved as that minimize variation of input at power supply voltage polarity reverse by that add voltage reversal function. Also, by using output filter, reduced harmonic of output line to line voltage components, and introduce state space analysis and forecast operation of rectifier. Such all items confirmed validity through simulation and an experiment.