• Proceedings of the KIEE Conference
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• 1991.11a
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• pp.207-209
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• 1991

This paper deals with voltage control method of PWM rectifier using current-controlled voltage type converter. A linearized model of the current-controlled rectifier is derived, which is used to examine the effect of controller gains to its dynamic responses. Through the simulation, it is shown that the proposed model is generally valid, which is confirmed by experimental results.

• Journal of Electrical Engineering and Technology
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• v.12 no.6
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• pp.2227-2236
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• 2017

In order to solve the neutral-point voltage fluctuation problem of three-phase three-level T-type inverters (TPTLTIs), the unbalance characteristics of capacitor voltages under different switching states and the mechanism of neutral-point voltage fluctuation are revealed. Based on the mathematical model of a TPTLTI, a feed-forward voltage balancing control strategy of DC-link capacitor voltages error is proposed. The strategy generates a DC bias voltage using a capacitor voltage loop with a proportional integral (PI) controller. The proposed strategy can suppress the neutral-point voltage fluctuation effectively and improve the quality of output currents. The correctness of the theoretical analysis is verified through simulations. An experimental prototype of a TPTLTI based on Digital Signal Processor (DSP) is built. The feasibility and effectiveness of the proposed strategy is verified through experiment. The results from simulations and experiment match very well.

• 연구논문집
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• s.26
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• pp.5-14
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• 1996

Test results of electromagnetic suspension (EMS) type urban transit maglev system are reported. Electromagnetic levitation system is a transportation system taking advantage of the attraction of normal conducting electromagnets to support and guide the train in combination with the linear induction traction motors. Urban Transit Maglev (UTM) Which is being developed by the maglev team in KIMM and the Hyundai Precision Company since 1995 consists of three bogies. In the first year, two types of Bogies are developed. Bogie I uses an analog controller for levitation and guidance control and is driven by two linear induction motors (LIM) mounted on the right and left side of module. Bogie II uses a digital controller and is driven by one LIM mounted along the center line of the bogie. Test results reported in this paper are those obtained with Bogie II with a digital controller. Also included in this paper is a brief explanation of the electromagnetic suspension levitation system which is being developed by the maglev team in KIMM.

• KIEE International Transactions on Power Engineering
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• v.4A no.3
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• pp.129-133
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• 2004

This paper deals with the design and implementation of a TCSC (Thyristor Controlled Series Capacitor) simulator, which is a module for an analog type power system simulator. Principally, it presents configuration of controller hardware/software and its experimental results. An analog type power system simulator consists of numerous power system components, such as various types of generator models, scale-downed transmission line modules, transformer models, switches and FACTS (Flexible AC Transmission System) devices. It has been utilized for the verification of the control algorithm and the study of system characteristics analysis. This TCSC simulator is designed for 50% line compensation rate and considered for damping resister characteristic analysis. Its power rate is three phase 380V 20kVA. For hardware extendibility, its controller is designed with VMEBUS and its main CPU is TMS320C32 DSP (Digital Signal Processor). For real time control and communications, its controller is applied to the RTOS (Real Time Operation System) for multi-tasking. This RTOS is uC/OS-II. The experimental results of capacitive mode and inductive mode operations verify the fundamental operations of the TCSC.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.4
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• pp.344-351
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• 2007

In this paper, we propose an approach to design multi-fuzzy controllers for the superheat and the low pressure that have an influence on energy efficiency and stabilization of air conditioning system with multi-evaporators. Air conditioning system with multi-evaporators is composed of compressor, condenser, several evaporators and several expansion valves. It is quite difficult to control the air conditioning system because the change of the refrigerant condition give an impact on the overall air conditioning system. In order to solve the drawback, we design multi-fuzzy controllers which control simultaneously both three expansion valve and one compressor for the superheat and the low pressure of air conditioning system. The proposed multi fuzzy controllers are given as a kinds of controller types such as a simplified fuzzy inference type. Here the scaling factors of each fuzzy controller are efficiently adjusted by Hierarchical Fair Competition-based Genetic Algorithms. The values of performance index of the simulation results of the A company type compare with simulation results of simplified inference type.

• Proceedings of the Korea Contents Association Conference
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• 2003.11a
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• pp.157-160
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• 2003

Web services can be invoked statically using a WSDL service interface and service implementation documents, or dynamically by retrieving the service type definitions and the service implementation via UDDI. But until now, couldn't do both at the same time. The Model View Controller pattern(MVC) supports both dynamic and static Web services. The MVC paradigm is a way of breaking an application, or even just a piece of an application's interface, into three parts: the model, the view, and the controller. Object-oriented methodologies have been applied to developing internet applications for increase reuse and expandability. I supposed a effective multimedia CMS(Contents Management Systems) using MVC.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.503-506
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• 1996

An integrated Robot control system for SCARA robot is developed. The system consists of an off-line programming(OLP), software and a robot controller using four digital signal processor(TMS32OC50). The OLP has functions of teaching task, dynamic simulator, three dimensional animation, and trajectory planning. To develop robust dynamic control algorithm, a new sliding mode control algorithm for the robot is proposed. The trajectory tracking performance of these algorithm is evaluated by implementing to SCARA robot(SM5 type) using DSP controller which has conventional PI-FF control algorithm. To make SCARA robot operate according to off-line teaching, an interface between OLP and robot controller in the integrated system is designed. To demonstrate performance of the integrated system, the proposed control algorithm is applied to the system.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.9
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• pp.1119-1125
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• 1999

In this paper, a decentralized multilevel-adaptive controller for a boiler-turbine system is designed by using multiple model adaptive method. It is applied to the drum type boiler-turbine system which is simplified from Boryung T/P #1,2 model. A linearlized model is decomposed into three subsystems by means of linear transformation. Then the DMC based on such subsystem is designed and a Multiple Model Adaptive Control(MMAC) scheme is applied for the purpose of the good tracking to variable load demands of the thermal power plant. The good performance of the designed controller is shown by simulations in various conditions that have the large step and ramp change of power demamd.

• Proceedings of the KIEE Conference
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• 2006.04a
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• pp.195-197
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• 2006

In this paper, an interface unit is designed to efficiently monitor transmission data in Controller Area Network(CAN)-based control systems. The CAN uses a serial multi master communication protocol that efficiently supports distributed real-time control with a very high level of data integrity, and communication speeds of up to 1Mbps. The interface unit is composed of a DSP controller which collects data on the CAN bus and transfers data to a personal computer via serial communication to save and display of interesting signals. The experimental system consists of three DSP controllers which represent electronic control units of a vehicle, an interface unit for analysing the data on the bus, and a graphic monitoring program coded on the Windows platform. The validity and the effectiveness of the proposed simple type of CAN interface unit are shown through the experimental results.

• Archives of design research
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• v.18 no.2 s.60
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• pp.201-210
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• 2005

In order to develop a more useful and ergonomically attractive remote controller, I peformed experiments with various subjects to define factors that may obstruct the usability of remote controllers for multifunction A/V appliances. I also performed the experiments to evaluate other factors that were created to improve the usability of them, and showed that remote controllers with the improved factors are more efficient and more attractive to use. I analyzed about 40 types of remote controllers for various A/V appliances to understand impediment factors of usability. By this analysis I found the factors that affected the usability of them, and developed three types of improved remote controllers for the next version of $Play@TV^{TM}$ also set the subjects with the task of usability tests with an existing remote controller and the three newly chosen remote controllers, and those results were analyzed qualitatively and quantitatively. The results showed that the 'B type' remote controller took less time to perform the same tasks by 9.2% than the existing remote controller. I concluded that the usability factors of remote controllers - function receptivity, presentation of a tactile clue, reasonable size and weight, how to arrange the main buttons, grouping of related functions - will be useful and effective to improve the usability of A/V appliances.