• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.5
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• pp.325-333
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• 2021

A 3 kW grid-tied PV inverter with Gallium nitride high-electron mobility transistor (GaN HEMT) for domestic commercialization was developed using boost converter and full-bridge inverter with LCL filter topology. Recently, many GaN HEMTs are manufactured as surface mount packages because of their lower parasitic inductance characteristic than standard TO (transistor outline) packages. A surface mount packaged GaN HEMT releases heat through either top or bottom cooling method. IGOT60R070D1 is selected as a key power semiconductor because it has a top cooling method and fairly low thermal resistances from junction to ambient. Its characteristics allow the design of a 3 kW inverter without forced convection, thereby providing great advantages in terms of easy maintenance and high reliability. 1EDF5673K is selected as a gate driver because its driving current and negative voltage output characteristics are highly optimized for IGOT60R070D1. An LCL filter with passive damping resistor is applied to attenuate the switching frequency harmonics to the grid-tied operation. The designed LCL filter parameters are validated with PSIM simulation. A prototype of 3 kW PV inverter with GaN HEMT is constructed to verify the performance of the power conversion system. It achieved high power density of 614 W/L and peak power efficiency of 99% for the boost converter and inverter.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.3
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• pp.35-43
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• 2007

In this paper, the inductive power collector using electromagnetic induction for vehicle such as the PRT(Personal Rapid Transit) system is suggested and son ideas for power collector design to improve tile power transfer performance are presented. And also, the analysis of the inductive power transfer system in conjunction with series resonant converter operating variable high frequency is shown. Of particular interest is the sensitivity of the complete system to variations in operational frequency and parameters. In inductive power transfer system electrical power is transferred from a primary winding in the form of a coil or tract to one or more isolated pick-up coils that my relative to the primary. The ability to transmit power without contact enables high reliability and easy maintenance that allows inductive power transfer system to be implemented in hostile environments. This technology has found application in many fields such as electric vehicles, PRT(Personal Rapid Transit) etc. But, low output power is generated due to a loosely coupled characteristic of the large air-gap. Therefore, we will show you various characteristic of inductive power transfer system as double layer construction of secondary winding, which was divided in half to increase both output current and output voltage, a model of power collector and parallel winding structure, a model of concentration/ decentralization winding and the effects of parameter and operational frequency variation.

• The Journal of the Korea Contents Association
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• v.9 no.6
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• pp.256-265
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• 2009

Laser output becomes output adjustment from 20 w to 100 w consecutively and time of exposure is available adjustment through water plant in 0.01 seconds. Pulse action can intercept laser beam periodically and supermarket pulse 0.1 $\sim$ between 1ms discharge consist and momentary laser output is increased to 5 $\sim$ 10. Specially, that must remove malignancy cell in womb nine escarps in the case of uterine cancer first of all stability of tube output about pulse by weight very, stable soft switching action area is defined without high frequency transformer leakage inductance ($L_1$) increase and additional series inductor insertion to converter the first main circuit securing zero voltage and marks of switching action in this research specially, because circulation current path of inductor ($L_f$) current is intercepted, converter the first main circuit switching component and spiritual enlightenment damage of high frequency transformer take decreasing greatly and high frequency the second stoppage department ($D_5,\;D_6$) becomes soft switching, and also, switching damage absorption quantity characteristic that can come to life again as subordinate have, and to become tube stabilization design and result that manufacture and experiment, brought result that improve of 10% than existing equipment, and if supplement as systematic late, it becomes thought to get into superior result.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.49 no.8
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• pp.73-81
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• 2012

In this paper, a novel phase locked loop has been proposed using an analog band-selection loop. When the PLL is out-lock, the PLL has a fasting locking characteristic with the analog band-selection loop. When the PLL is near in-lock, the bandwidth becomes narrow with the fine loop. A frequency voltage converter is introduced to improve a stability and a phase noise performance. The proposed PLL has been designed based on a 1.8V $0.18{\mu}m$ CMOS process and proved by HSPICE simulation.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.35 no.3
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• pp.328-334
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• 1999

A fish pump makes very important roles in an automation system of an aquaculture farm, thus it has been used widely in order to transfer fishes from one place to the other place automatically. In spite of its significant roles, the efforts for developing performance and promoting efficiency of the fish pump are not sufficient yet. In this paper, a method which makes the fish pump automation system is suggested. Automation of the fish pump can be accomplished by using variable voltage and variable frequency inverter system including induction motors. Especially, very simple logic to generate Pulse width Modulation(PWM) wave to control induction motor efficiently and three steps speed control method to regulate liquid quantity of the fish pump simply are suggested. Owing to the simplifies speed control and PWM wave generation technique, a cheaper microprocessor, 80C196KC, than a digital signal Processor(DSP) can be used to operate control algorithm in induction motor systems for real time control Also, a new idea of remote control for the simplifies novel inverter system by Programmable logic Controller(PLC) without special output unit, digital to analog converter(D/A), is suggested in this paper. Consequently the function of reliability, availability and serviceability of the fish pump system are developed. It will be expected to contribute expanding of application of the fish pump in aquaculture farms because the system can reduce energy consumption and some difficulties according to manual operation prominently.

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.1
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• pp.22-28
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• 2015

This paper proposes column-parallel three step Single Slope Analog-to-Digital Converter (SS-ADC) for high frame rate VGA CMOS Image Sensors (CISs). The proposed three step SS-ADC improves the sampling rate while maintaining the architecture of the conventional SS-ADC for high frame rate CIS. The sampling rate of the three-step ADC is increased by a factor of 39 compared with the conventional SS-ADC. The proposed three-step SS-ADC has a 12-bit resolution and 200 kS/s at 25 MHz clock frequency. The VGA CIS using three step SS-ADC has the maximum frame rate of 200 frames/s. The total power consumption is 76 mW with 3.3 V supply voltage without ramp generator buffer. A prototype chip was fabricated in a $0.13{\mu}m$ CMOS process.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.64 no.3
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• pp.175-181
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• 2015

In this paper, the neuromuscular electrical stimulation medical devices for non-implantable incontinence treatment other than vaginal insertion type was developed and commercialized. The structure of medical devices for electrical stimulation based on the anatomy of the pelvic floor muscle designed. Then, the optimum parameters that may be effective in pelvic floor muscle electrical stimulation was set. The circuit system based on the optimum parameters were designed and manufactured. The frequency of the pulse voltage for electrical stimulation is 75[Hz], the pulse width is 300[${\mu}s$], the development of medical devices was to have seven program functions to the various treatments. The circuit system of medical devices was composed of microcontroller, comparator and converter. The performance of the developed circuit system in KTC(Korea Testing Certification) were carried out medical equipment inspection test. Test results, test specifications were satisfied with the medical device, the performance was verified to be commercialized as a medical device. The development of medical devices were validated risk assessment and product performance through a software validation. Commercialization of medical equipment was acquired to enable the certification standards of the international standard IEC 60601-1.

• 전기의세계
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• v.22 no.1
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• pp.35-41
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• 1973

An automatic point traffic control method is recommended for more idealistic traffic flow over coarse road netowrks. The automatic control apparatus recommended, consists of a transceiver, amplifier, digital-to-analog converter, signal light controller for emergency and steady state, and digital counter as monitor. The transmitter sends a signal to the target vy means of Microwave-FM-CW and a diode detector picks up the echo signal. Thus the operation of the entire system will be carried out through an open loop state. Some factors necessary for an ideal detector system are rapid response, longevity and stability. An analytical method of the Doppler effect substitutes the conventional frequency deviation into the amplitude of detector output. The changing rate of amplitude is proportional to the voltage of the detector output. Some induced formula from Maxwell's radiation field theory ensures this new method, and, new method, and proves the fact with an experimental data presentation. Stability depends upon Klystron as an oscillator and a diode as a detector. the transceiver installation affects on the response and sensitivity of the system. In accordance with the detector output, several targets are easily classified by amplitudes on the scope. The traffic flow, i.e., target movement which is analyzed by the amplitude method, is shown through the scope and indicates it on the digital counter. The best efficiency for the amplitude analysis can be attained through use of an antenna having the highest sensitivity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.57-60
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• 2004

This paper presents multibit Sigma-Delta ADC using Leslie-Singh Structure to Improve nonlinearity of feedback loop. 4-bit flash ADC for multibit Quantization in Sigma Delta modulator offers the following advantages such as lower quantization noise, more accurate white-noise level and more stability over single quantization. For the feedback paths consisting of DAC, the DAC element should have a high matching requirement in order to maintain the linearity performance which can be obtained by the modulator with a multibit quantizer. Thus a Sigma-Delta ADC usually adds the dynamic element matching digital circuit within feedback loop. It occurs complexity of Sigma-Delta Circuit and increase of power dissipation. In this paper using the Leslie-Singh Structure for improving nonliearity of ADC. This structure operate at low oversampling ratio but is difficult to achieve high resolution. So in this paper propose improving loop filter for single-bit feedback multi-bit quantization Sigma-Delta ADC. It obtained 94.3dB signal to noise ratio over 615kHz bandwidth, and 62mW power dissipation at a sampling frequency of 19.6MHz. This Sigma Delta ADC is fabricated in 0.25um CMOS technology with 2.5V supply voltage.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.1
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• pp.40-50
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• 2016

In order to recover the power system during the wide power outage or power failure in the power plant, black start system should be properly operated without any problem. Especially power for black start in the geographically isolated areas of electric island is supplied from small emergency start-up generator, and loads are aux systems of gas turbines such as SFC(Static frequency converter). This paper introduces the international practices to overcome the voltage drop problem with harmonics of the system having the DC output such as SFC during black start in weak feed system and analyzes the relationship between house load inputs and harmonics. By varying the house load and input of power supply, this paper identified boundaries between weak feed and strong feed power. In order to verify the theory of stable condition in weak feed power system with DC output, house load is simulated using ETAP. Additionally MATLAB was used for harmonic analysis between the load inertia moment and non load inertia moment.