• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2508-2513
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• 2003

This paper presents a nuclear steam generator tube inspection/maintenance robot system. The robot assists in automatic non-destructive testing and the repair of nuclear steam generator tubes welded into a thick tube sheet that caps a hemispherical or quarter-sphere plenum which is a high-radiation area. For easy carriage and installation, the robot system consists of three separable parts: a manipulator, a water-chamber entering and leaving device for the manipulator and a manipulator base pose adjusting device. A software program to control and manage the robotic system has been developed on the NT based OS to increase the usability. The software program provides a robot installation function, a robot calibration function, a managing and arranging function for the eddy-current test, a real time 3-D graphic simulation function which offers remote reality to operators and so on. The image information acquired from the camera attached to the end-effecter is used to calibrate the end-effecter pose error and the time-delayed control algorithm is applied to calculate the optimal PID gain of the position controller. The developed robotic system has been tested in the Ulchin NPP type steam generator mockup in a laboratory.

• Journal of Power Electronics
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• v.17 no.1
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• pp.232-241
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• 2017

Advanced control algorithms must be used to make wind power generation truly cost effective and reliable. In this study, we develop a new and simple control scheme that employs model predictive control (MPC), which is used in permanent magnet synchronous generators and grid-connected inverters. The proposed control law is based on two points, namely, MPC-based torque-current control loop is used for the generator-side converter to reach the maximum power point of the wind turbine, and MPC-based direct power control loop is used for the grid-side converter to satisfy the grid code and help improve system stability. Moreover, a simple prediction scheme is developed for the direct-drive wind energy conversion system (WECS) to reduce the computation burden for real-time applications. A small-scale WECS laboratory prototype is built and evaluated to verify the validity of the developed control methods. Acceptable results are obtained from the real-time implementation of the proposed MPC methods for WECS.

• KIISE Transactions on Computing Practices
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• v.23 no.1
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• pp.13-27
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• 2017

This paper presents a tool that automatically generates mobile web applications from user interface (UI) models which are based on PELUM (Pattern and Event based Logical User Interface Modeling). PELUM is a method for the effective development of UI-centered embedded systems via UI modeling. The proposed tool consists of a model editor and a code generator. The former provides an environment for modeling a Logical UI Model (LUM) and a Programming Interface Model (PIM) on the web. On the other hand, the code generator sets the screen configuration and events' behavior, according to the LUM, synthesizing a local database schema according to the PIM, and then generates an executable mobile web app. It also can produce mashup web apps by receiving an open API address via the PIM. The generated mobile web apps follow the Model-View-Controller (MVC) architecture in order for users to easily customize them. The proposed tool enables them to generate mobile web apps that can be executed on various devices by modeling logical UIs on the web.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.64 no.3
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• pp.143-145
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• 2015

One of the many problems besetting the converter designer is being able to design a switching power supply that can operate in the range of very wide input voltage. Specially, in an emergency diesel generator system, the AVR(Automatic Voltage Regulator) is a regulator which regulates the output voltage of the generator at a nominal constant voltage level. In addition, the AVR must be operated in very wide input voltage. Therefore, a power supply for the AVR must be operated at the very wide input voltage range. In this paper, a quasi-resonant flyback power supply with very wide input voltage range is proposed. Also, the performance of the proposed power supply is demonstrated through experiments.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.172-174
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• 1995

About a half of Electric power is generated by nuclear power plants in korea. So, the stable operation of nuclear power plant is very important for suppling the essential national electric power. A S/G(Steam Generator) level control is the most difficult system in PWR(Pressurized Water Reactor) nuclear power plant. Because of the non-linear and the non-nominal response of S/G level control, it Is very difficult to control the level by automatic mode or manual mode. The goal of this study is to establish and verify a advanced control algorithm by analyzing, modelling, stability calculation, controller parameter calculation, simulation for S/G level control system.

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.167-170
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• 1993

This paper deals with AVR(Automatic Voltage Regulator) control1or design of synchronous generator adapting AC indirect excitation system. The simulation results are presented in frequency and tine domain for two plants(A and B). Try and error method for compensator design is used.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.9C
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• pp.652-660
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• 2008

Applications running under embedded systems require various device drivers designed for different types and versions of the OS to manage resources effectively. In this paper, an automated device driver generator system which can generate the device drivers to be used in newer versions the target OS is proposed. In the proposed system, the structures of device drivers of specific OS are designed in the templates and stored in a library, and the target device drivers are generated by adding codes to the stored templates. Once device drivers are generated, they are registered into the kernel. The experimental results show that data transfer time has been slightly increased when compared against manually created drivers for TFT-LCD driver, USB interface keyboard/mouse driver, and AC'97 controller drivers. The code size for the generated drivers after compilation has also been increased slightly when compared with manually designed device drivers.

• Journal of Power Electronics
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• v.17 no.6
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• pp.1587-1599
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• 2017

This paper proposes a real-time implementation of an optimal operation of a double stage grid connected wind power system incorporating an active power filter (APF). The system is used to supply the nonlinear loads with harmonics and reactive power compensation. On the generator side, a new adaptive neuro fuzzy inference system (ANFIS) based maximum power point tracking (MPPT) control is proposed to track the maximum wind power point regardless of wind speed fluctuations. Whereas on the grid side, a modified predictive current control (PCC) algorithm is used to control the APF, and allow to ensure both compensating harmonic currents and injecting the generated power into the grid. Also a type 2 fuzzy logic controller is used to control the DC-link capacitor in order to improve the dynamic response of the APF, and to ensure a well-smoothed DC-Link capacitor voltage. The gained benefits from these proposed control algorithms are the main contribution in this work. The proposed control scheme is implemented on a small-scale wind energy conversion system (WECS) controlled by a dSPACE 1104 card. Experimental results show that the proposed T2FLC maintains the DC-Link capacitor voltage within the limit for injecting the power into the grid. In addition, the PCC of the APF guarantees a flexible settlement of real power exchanges from the WECS to the grid with a high power factor operation.

• Journal of the Microelectronics and Packaging Society
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• v.17 no.4
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• pp.73-76
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• 2010

A two-facet approach was used to investigate the parametric performance of functional high-speed DDR3 (Double Data Rate) DRAM (Dynamic Random Access Memory) die placed in different types of BGA (Ball Grid Array) packages: wire-bonded BGA (FBGA, Fine Ball Grid Array), flip-chip (FCBGA) and lead-bonded $microBGA^{(R)}$. In the first section, packaged live DDR3 die were tested using automatic test equipment using high-resolution shmoo plots. It was found that the best timing and voltage margin was obtained using the lead-bonded microBGA, followed by the wire-bonded FBGA with the FCBGA exhibiting the worst performance of the three types tested. In particular the flip-chip packaged devices exhibited reduced operating voltage margin. In the second part of this work a test system was designed and constructed to mimic the electrical environment of the data bus in a PC's CPU-Memory subsystem that used a single DIMM (Dual In Line Memory Module) socket in point-to-point and point-to-two-point configurations. The emulation system was used to examine signal integrity for system-level operation at speeds in excess of 6 Gb/pin/sec in order to assess the frequency extensibility of the signal-carrying path of the microBGA considered for future high-speed DRAM packaging. The analyzed signal path was driven from either end of the data bus by a GaAs laser driver capable of operation beyond 10 GHz. Eye diagrams were measured using a high speed sampling oscilloscope with a pulse generator providing a pseudo-random bit sequence stimulus for the laser drivers. The memory controller was emulated using a circuit implemented on a BGA interposer employing the laser driver while the active DRAM was modeled using the same type of laser driver mounted to the DIMM module. A custom silicon loading die was designed and fabricated and placed into the microBGA packages that were attached to an instrumented DIMM module. It was found that 6.6 Gb/sec/pin operation appears feasible in both point to point and point to two point configurations when the input capacitance is limited to 2pF.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.369-372
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• 2002

In this research, a vision system for detecting tool breakage which is hardly detected by such indirect in-process measurement method as acoustic emission, cutting torque and motor current was developed and embedded into a PC-NC system. The vision system consists of CMOS image sensors, a slit beam laser generator and an image grabber board. Slit beam laser was emitted on the tool surface to separate the tool geometry well from the various obstacles surrounding the tool. An image of tool is captured through two steps of signal processing, that is, median filtering and thresholding and then the tool is estimated normal or broken by use of change of the centroid of the captured image. An air curtain made by the jetting high-pressure air in front of the lens was devised to prevent the vision system from being contaminated by scattered coolant, cutting chips in cutting process. To embed the vision system to a Siemens PC-NC controller 840D NC, an HMI(Human Machine Interface) program was developed under the Windows 95 operating system of MMC103. The developed HMI is placed in a sub window of the main window of 840D and this program can be activated or deactivated either by a soft key on the operating panel or M codes in the NC part program. As the tool breakage is detected, the HMI program emit a command for automatic tool change or send alarm to the NC kernel. Evaluation test in a high speed tapping center showed the developed system was successful in detection of the small-radius tool breakage.