• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.1
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• pp.59-65
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• 2021

This study proposes a dead-time implementation method suitable for cell voltage control of a cascaded H-bridge (CHB) inverter. The PWM module of an existing microcontroller cannot generate a maximum voltage due to the dead-time effect when used as the cell controller of the CHB inverter. In the proposed method, the operation method of the PWM module was changed without using the dead time module included in the existing microcontroller, so that the cell output voltage can be increased to the maximum voltage without voltage discontinuity. During the maximum voltage generation period, the full turn-on state can be maintained without unnecessary switching. The validity of the proposed method is confirmed through an experiment.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.50-53
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• 1999

In this paper, we developed a LCU which can be apply Radiation Monitoring System. LCU composed of Controller and Detector Pulse Input Module and so on. we explained concept of PIG Monitor and a study of Radiation Algorithm. Keywords RMS, LCU, DPIM, CPM

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.9
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• pp.1372-1377
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• 1990

We constructed an intelligent tutoring system that compose four devices i.e. intelligent interface, acqusition module, tutoring controller and tutorial knowledge. We implemented the intelligent tutoring system using prolog as an authoring language in the ultrix os under VAX-11/750, and we propose goal opriented tutoring system algorithm.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.19 no.4
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• pp.37-43
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• 2011

Lunar exploration program has been prepared with the aim of launch in the 2020's. As part of it, a lunar lander demonstrator has been developed which is the model for verifying all the system, such as structure, propulsion and control system before launch to deep space. After verifying all the system, the demonstrator will be evaluated by flight test. This paper deals with path tracking controller based on thrusters for the demonstrator. For this, first we derive equations of motion according to the allocation of thrusters and design the path tracking controller. The signal generated from the controller is continuous so PWPF(Pulse-Width Pulse-Frequency) modulator is adopted for generating on/off signal. Finally MATLAB simulation is performed for evaluating the path tracking ability and the final landing velocity.

• Journal of Power System Engineering
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• v.17 no.2
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• pp.38-45
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• 2013

In this study, for carrying out the spray and combustion experiment using a Common Rail Direct Injection(CRDI) system, the controller was fabricated to drive a high speed camera, a injector and a laser beam sequentially at a low cost. CB280 module of one-chip micro processer was used for the controller. In order to confirm responsibility and utility of the controller, the current drive performance, the spray behavior and the injection rate were tested and analyzed under various experimental conditions. As this research results, we found that the fabricated controller was able to control the devices for the spray experiment precisely with the input value in program and it had the dynamic load responsibility and repetition. Also, we found that the injection rates of our experimental results were higher than those of others at the same injection pressure and the controller connected with the laser system and the data acquisition system had validity for carrying out the spray visualization experiment.

• Smart Structures and Systems
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• v.26 no.4
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• pp.469-480
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• 2020

This is the first research on the smart control and vibration analysis of a Graphene nanoplatelets (GPLs) Reinforced Composite (GPLRC) porous cylindrical shell covered with piezoelectric layers as sensor and actuator (PLSA) in the framework of numerical based Generalized Differential Quadrature Method (GDQM). The stresses and strains are obtained using the First-order Shear Deformable Theory (FSDT). Rule of the mixture is employed to obtain varying mass density and Poisson's ratio, while the module of elasticity is computed by modified Halpin-Tsai model. The external voltage is applied to sensor layer and a Proportional-Derivative (PD) controller is used for sensor output control. Governing equations and boundary conditions of the GPLRC cylindrical shell are obtained by implementing Hamilton's principle. The results show that PD controller, length to radius ratio (L/R), applied voltage, porosity and weight fraction of GPL have significant influence on the frequency characteristics of a porous GPLRC cylindrical shell. Another important consequence is that at the lower value of the applied voltage, the influence of the smart controller on the frequency of the micro composite shell is much more significant in comparison with the higher ones.

• Journal of Biosystems Engineering
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• v.25 no.4
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• pp.301-310
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• 2000

An autonomous tractor system was developed and its performance was evaluated. The system consisted of a tractor system of and a remote control station. The tractor and the remote control station communicated each other via wireless modems. The tractor had a DGPS(differential global positioning system), sensors, a controller and a modem. The DGPS collected position data and the tractor status was estimated. The information of tractor status and sensors was transferred to the remote control station. Then, the control station determined the control data such as steering angles using a fuzzy controller. The fuzzy controller used the information from the DGPS, sensors, and GIS(geographic information system) data. The control data were obtained by remote signal processing at the control station The control data for autonomous operation were transferred to the tractor controller. The performances of an autonomous tractor were evaluated for various speeds, different initial positions and different initial headings. About 1.3 seconds of time lag was occurred in transferring the tractor status data and the control data. Compensation the time lag, about 27cm deviation was observed at the speed of 0.5m/s and 37cm at the speed of 1m/s. Error caused mainly by the time lag and it would be reduced by developing a full-duplex radio module for controlling the remote tractor.

• Journal of Power Electronics
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• v.15 no.3
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• pp.830-840
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• 2015

The H-bridge inverter is the fundamental power cell of the cascaded distribution static synchronous compensator (DSTATCOM). Thus, cell reliability is important to the compensation performance and stability of the overall system. The concept of the power electronics building block (PEBB) is an ideal solution for the power cell design. In this paper, an H-bridge inverter-based “plug and play” HPEBB is introduced into the main circuit and the controller to improve the compensation performance and reliability of the device. The section that discusses the main circuit primarily emphasizes the design of electrical parameters, physical structure, and thermal dissipation. The section that presents the controller part focuses on the principle of complex programmable logic device -based universal controller This section also analyzes typical reliability and anti-interference issues. The function and reliability of HPEBB are verified by experiments that are conducted on an HPEBB test-bed and on a 10 kV/± 10 Mvar DSTATCOM industrial prototype.

• Journal of the Korea Computer Industry Society
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• v.2 no.4
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• pp.425-434
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• 2001

In this paper, a series of processes to configure a feedback control system by using a PID controller in a programmable logic controller (PLC). The PLC (SIMATIC S7-400) with a PID module (FM455C) is connected by online to an IBM PC with the Windows environment, which serves as a PLC programmer. PID controllers including P/PD/PI controllers have been designed in order to show design procedures, and finally, a PID controller for the plant of cart system. Performances of the control system have been investigated by the MATLAB simulation, the simulation in the PLC programmer. Physical performances have been recorded and examined for the real cart system.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.7
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• pp.868-875
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• 1999

In this paper, digital motor control center using protection relay is developed in order to protect power systems by means of timely fault detection and diagnosis during operation for induction motor which have various load environments and capacities in power systems. Digital motor control center is employed by power supervisory control systems without separate remote terminal unit and transducers adding communicational ability. Also we develope a maximum demand controller to control the load effectively at peak status and a power factor controller to minimize real power losses and improve the power factor. Therefore, when using the developed controller, real time computation is possible by loading DSP in hardware and applying real-time kernel which can convert each algorithm to task module.