• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.2
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• pp.138-147
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• 2005

This paper presents a SPMSM(Surface-mounted Permanent Magnet Synchronous Motor) servo drive system using high performance TMS320F2812 DSP for the industrial application. The DSP(Digital Signal Processor) Controller enables an enhanced real time algorithm and cost-effective design intelligent for only exclusively motor drives which can be yield enhanced operation, fewer system components, lower control system cost, increased efficiency and high performance. The suggested system contain speed and current sensing circuits, SVPWM(Space Vector Pulse Width Modulation) and I/O interface circuit. The developed servo drive control system showns a good response characteristics results and high performance features in general purposed 400[w] machine. This system can achieve cost reduction and size minimization of controllers.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.4
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• pp.185-192
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• 2005

This paper proposes a DRMS(Distribution Remote Management System) which can enhance highly the economics of automatic metering system and the power quality supplied to the electric customer improving the efficiency of the meter reading, voltage management and load management work by realizing the remote meter reading, the remote voltage management and the remote load management based on the ADWHM(Advanced Digital Watt Hour Meter). The DRMS is designed so that the voltage management and load management work in remote site can be processed by collecting the voltage pattern and current pattern as well as watt hour data from all ADWHMs one time every month regularly or from special ADWHMS several time irregularly, A new on-line voltage and load management strategy based on the ADWHM is designed by analyzing the existing voltage management and load management process. Also, DRMS is designed so that watt-hour data, voltage pattern data, load pattern data and power factor data can be collected selectively according to the selection of user to assist effectively the methodology. Remote management program and database of the DRMS are implemented based on Visual C++, MFC and database library of MS. Also, DRMS is designed so as to communicate with the ADWHM using RS232C-TCP/IP converter and ADSL. The effectiveness of the remote metering function is proven by collecting and analyzing the data after ADWHMs installed in any site. The developed strategy and program also is verified through the simulation of voltage management and load management.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.1
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• pp.48-55
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• 2014

These Xenon flashlamp power supply for Ultra Violet has converter with high voltage conversion ratio. General model is composed of transformer with high voltage conversion ratio and voltage doubler rectifier circuit. Purpose of power supply leads dielectric breakdown of Xenon flashlamp and passes current rapidly. When passing current, it has to limit current to avoid over-heat, damage of electrode and acceleration of gas oxidation which are cause of performance degradation of lamps. Generally, inductors and resistors, which are called as "Ballast," are used to limit currents. Generally, Transformer has high turn ratio to make high voltages. But we can get high voltages using the transformer with low turn ratio which is driven with self resonance. Also, an advantage of self resonance is to make a circuit simply through impedance of transformer in resonance frequency which filters output voltage. As using an unique impedance of transformer, the circuit does not need other impedance elements like the ballast. So the power supply assures high efficiency of the arc discharge.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.5
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• pp.10-24
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• 2007

In the dissertation, a power conversion system for fuel cell is composed of a PWM inverter with LC filter in order to convert fuel cell voltage to a single phase 220[V]. In addition, new insulated DC-DC converters are proposed in order that fuel cell voltage is boosted to 380[V]. In this paper, it requires smaller components than existing converters, which makes easy control. The proposed DC-DC converter controls output power by the adjustment of phase-shift width using switch $S_5\;and\;S_6$ in the secondary switch which provides 93-97[%] efficiency in the wide range of output voltage. Fuel cell simulator is implemented to show similar output characteristics to actual fuel cell. Appropriate dead time td enables soft switching to the range where the peak value of excitation current in a high frequency transformer is in accordance with current in the primary circuit. Moreover, appropriate setting to serial inductance La reduces communication loss arisen at light-load generator and serge voltage arisen at a secondary switch and serial diode. Finally, TMS320C31 board and EPLD using PWM switching technique to act a single phase full-bridge inverter which is planed to make alternating current suitable for household

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.672-682
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• 2020

The Korea Nowadays, which is research on digital twin technology for efficient operation in various industrial/manufacturing sites, is being actively conducted, and gradual depletion of fossil fuels and environmental pollution issues require new renewable/eco-friendly power generation methods, such as wave power plants. In wave power generation, however, which generates electricity from the energy of waves, it is very important to understand and predict the amount of power generation and operational efficiency factors, such as breakdown, because these are closely related by wave energy with high variability. Therefore, it is necessary to derive a meaningful correlation between highly volatile data, such as wave height data and sensor data in an oscillating water column (OWC) chamber. Secondly, the methodological study, which can predict the desired information, should be conducted by learning the prediction situation with the extracted data based on the derived correlation. This study designed a workflow-based training model using a machine learning framework to predict the pressure of the OWC. In addition, the validity of the pressure prediction analysis was verified through a verification and evaluation dataset using an IoT sensor data to enable smart operation and maintenance with the digital twin of the wave generation system.

• Korean Journal of Optics and Photonics
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• v.31 no.3
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• pp.142-147
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• 2020

In this paper, we report highly efficient second harmonic generation of continuous-wave Yb fiber lasers incorporating a periodically poled LiTaO₃ device (MgO:PPSLT) as a frequency converter. The seed laser output from a Yb fiber master oscillator using a Fabry-Perot feedback cavity was amplified in a Yb fiber amplifier stage, yielding 28.5 W of linearly polarized output at 1064 nm in a beam with beam quality, M², of ~1.07. Second harmonic generation was achieved by passing the laser beam through MgO:PPSLT. Under optimized conditions, we obtained 11.1 W of green laser output at 532 nm for an incident signal power of 25.0 W at 1064 nm, corresponding to a conversion efficiency of 44.4%. The detailed investigation to find the optimized operating conditions and prospects for further improvement are discussed.

• Korean Journal of Optics and Photonics
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• v.11 no.4
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• pp.271-278
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• 2000

We have fabricated and analyzed the lasing characteristics of 1.3$\mu\textrm{m}$ Spot-Size-Converter (SSC) integrated Fabry-Perot (FP) laser diodes, which are very promising light sources for optical subscriber networks. SSC-LDs has been developed by BIB (buttjoint-built-in) coupling and selective MOVPE growth. High-performances were achieved such as the slope efficiency from the SSC facet of 0.23-0.32 mW/mA, the full-width at the half maximum of the far-field pattern (FFP) of 9.5$^{\circ}$~12.3$^{\circ}$, the alignment tolerances of $\pm$2.3$\mu\textrm{m}$ and $\pm$2.5$\mu\textrm{m}$ within the extra-coupling loss of 1 dB for the vertical and parallel directions, respectively. These experimental results were compared to theoretical ones in order to clarify the operational problems and give a good design direction of the fabricated SSC-LDs. It was revealed that an asymmetric output power from the facets, an irrelevancy of FFP and the waveguide structure around SSC facet region, and a poor temperature characteristics were originated from the scattering in the BIB and SSC sections and SHB effect in the active section for the first time.t time.

• International Journal of Automotive Technology
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• v.8 no.3
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• pp.375-382
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• 2007

The multi-driver off-road vehicle drive-line consists of many components, with close connections among them. In order to design and analyze the drive-line efficiently, a modular methodology should be taken. The aim of a modular approach to the modeling of complex systems is to support behavior analysis and simulation in an iterative and thus complex engineering process, by using encapsulated submodels of components and of their interfaces. Multi-driver off-road vehicles are comparatively complicated. The driving-line is an important core part to the vehicle, it has a significant contribution to the performance. Multi-driver off-road vehicles have complex driving-lines, so performance is heavily dependent on the driving-line. A typical off-road vehicle's driving-line system consists of a torque converter, transmission, transfer case and driving-axles, which transfers the power generated by the engine and distributes it effectively to the driving wheels according to the road condition. According to its main function, this paper proposes a modularized approach for design and evaluation of the vehicle's driving-line. It can be used to effectively estimate the performance of the driving-line during the concept design stage. Through an appropriate analysis and assessment method, an optimal design can be reached. This method has been applied to practical vehicle design, it can improve the design efficiency and is convenient to assess and validate the performance of a vehicle, especially of multi-driver off-road vehicles.

• Journal of Biosystems Engineering
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• v.43 no.2
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• pp.94-102
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• 2018

Purpose: In this study, a maintenance free super-capacitor battery charging system based on the photovoltaic module, to be used in agricultural electric carriers, was developed and its charging characteristics were studied in detail. Methods: At first, the electric carrier system configuration is introduced and the electric control components are presented. The super-capacitor batteries and photovoltaic module used in the experiment are specified. Next, the developed charging system consisting of a constant current / constant voltage Buck converter as the charging device and a super-capacitor cell as a balancing device are initiated. The proposed circuit design, a developed PCB layout of each device and a proportional control to check the current and voltage during the charging process are outlined. An experiment was carried out using a developed prototype to clarify the effectiveness of the proposed system. A power analyzer was used to measure the current and voltage during charging to evaluate the efficiency of the energy storage device. Finally, the conclusions of this research are presented. Results: The experimental results show that the proposed system successfully controls the charging current and balances the battery voltage. The maximum voltage of the super-capacitor battery obtained by using the proposed battery charger is 16.2 V, and the maximum charging current is 20 A. It was found that the charging time was less than an hour through the duty ratio of 95% or more. Conclusions: The developed battery charging system was successfully implemented on the agricultural electric carriers.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.9
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• pp.47-54
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• 2008

Cost reduction requires lowering number of power devices used in the converter driving SRM. This is quite feasible in SRM drive systems than in other drive systems. This paper deals with analysis and simulation of a novel two phase SRM. A novel two phase SRM has high performance, self-starling capability, high efficiency, and low manufacturing cost. Additionally, the stator back iron does not experience any flux reversal as the flux is in the same direction whether phase A or B is excited leading to a greater reduction in core losses. The magnetic analysis and design considerations of the novel two phase SRM have been obtained by the finite element analysis (FEM).