• 전기학회논문지P
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• 제54권4호
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• pp.211-216
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• 2005

In this paper a robust controller using adaptive backstepping technique is proposed to control the speed of wind power generation system. To make wind power generation truly cost effective and reliable, advanced and robust control algorithms are derived to on-line adjust the excitation winding voltage of the generator based on both mechanical and electrical dynamics. This method is shown to be able to achieve smooth and asymptotic rotor speed tracking, as justified by analysis and computer simulation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 학술대회 논문집 전문대학교육위원
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• pp.128-131
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• 2005

In this paper a robust controller using adaptive backstepping technique is proposed to control the speed of a wind turbine system. To make wind power generation truly cost effective and reliable, advanced and robust control algorithms are derived to on-line adjust the excitation winding voltage of the generator based on both mechanical and electrical dynamics. This method is shown to be able to achieve smooth and asymptotic rotor position tracking, as justified by analysis.

• 연구논문집
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• 통권22호
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• pp.85-96
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• 1992

A mass flow controller(MFC) is commonly used in the semiconductor industries to control the flow rate of various process gases. The measurement and precise control of the of flow rate the gas are the key for a succesful IC fabrication. To eventually design a reliable MFC, a pre-proto type MFC was built and its flow characteristics were investigated. Most of the functional components of the pre-proto type were built for the present study, but the remainder were adopted from a commercial unit. The flow control characteristics were compared with that of a standard MFC. Major dimensions of an MFC for 0-10 SLM capacity were suggested.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1227-1229
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• 2007

In this paper a robust controller using adaptive backstepping technique is proposed to control the position of wind power generation system. To make wind power generation truly cost effective and reliable, advanced and robust control algorithms are derived to on-line adjust the excitation winding voltage of the generator based on both mechanical and electrical dynamics. This method is shown to be able to achieve smooth and asymptotic rotor speed tracking, as justified by analysis and computer simulation.

• Nuclear Engineering and Technology
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• 제46권3호
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• pp.381-386
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• 2014

A highly reliable safety class controller for NPPs (Nuclear Power Plants) is mandatory as even a minor malfunction can lead to disastrous consequences for people, the environment or the facility. In order to enhance the reliability of a safety class digital controller for NPPs, we employed a diversity approach, in which a PLC-type controller and a PLD-type controller are to be operated in parallel. We built and used structured testbenches based on the classes supported by UVM for functional verification of the PLD-type controller designed for NPPs. We incorporated a UVM register model into the testbenches in order to increase the controllability and the observability of the DUT(Device Under Test). With the increased testability, we could easily verify the datapaths between I/O ports and the register sets of the DUT, otherwise we had to perform black box tests for the datapaths, which is very cumbersome and time consuming. We were also able to perform constrained random verification very easily and systematically. From the study, we confirmed the various advantages of using the UVM register model in verification such as scalability, reusability and interoperability, and set some design guidelines for verification of the NPP controllers.

• Journal of Electrical Engineering and Technology
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• 제5권2호
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• pp.197-208
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• 2010

Unified power flow controller (UPFC) is the most reliable device in the FACTS concept. It has the ability to adjust all three control parameters effective in power flow and voltage stability. In this paper, a linearized model of a power system installed with a UPFC has been presented. UPFC has four control loops that by adding an extra signal to one of them, increases dynamic stability and load angle oscillations are damped. In this paper, after open loop eigenvalue (electro mechanical mode) calculations, state-space equations have been used to design damping controller and it has been considered to influence active and reactive power flow durations as the input of damping controller, in addition to the common speed duration of synchronous generators as input damper signal. To increase stability, further Lead-Lag and LQR controllers, a novel on-line adaptive controller has been used analytically to identify power system parameters. Closed-loop calculations of the electro mechanical mode verify the improvement of system pole placement after controller designing. Suitable operation of adaptive controller to decrease rotor speed oscillations against input mechanical torque disturbances is confirmed by the simulation results.

• Journal of Advanced Marine Engineering and Technology
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• 제36권1호
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• pp.133-140
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• 2012

In this study, a reliable control scheme with PID combined controller will be considered. The combined controller in this study is PID algorithm with parameters tuned by using ILC (iterative learning control) approach. The controller was applied to the vibration isolator using an induction motor which works as an actuator. This isolator is developed to eliminate the influence of vibration from rotating machineries on the small ship. The NI cRIO real time controller with FPGA is loaded to get or generate control signals. Crank mechanism which converts rotating energy into translational force is adopted and the relation between control force and torque generated from actuator is also analyzed. A Labview program is composed for controlling practice. Experimental results will be described to show the effectiveness of the proposed control schemes.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.67-67
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• 2000

In this paper, a hybrid type fuzzy controller is proposed to maintain molten steel level stable and reliable manner in high speed continuous casting regardless of various disturbances such as casting speed change, tundish weight variation, 치ogging/undoning of SEN(Submerged Entry Nozzle), periodic bulgings, etc. To accomplish this purpose, hardware filter and software filer are carefully designed to eliminate high frequency noise and to smooth input signals from harsh environments. In order to minimize the molten steel level variations from various disturbances the controller uses hybrid type control term: fuzzy logic term, proportional term, differential term and nonlinear feedback compensation tenn. The proposed controller is applied tn commercial mini-mill plant and shows considerable improvement in minimizing the molten steel variation.

• 연구논문집
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• 통권30호
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• pp.79-92
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• 2000

Chopper and sensors failures resulting from electric shock and mechanical vibration generated by rail irregularities are the serious problem deteriorating the performance in the electromagnetic suspension systems. Thus, this paper proposes a reliable output feedback control scheme for the electromagnetic suspension systems in the present of chopper, gap sensor and acceleration sensor failures. The designed controller is an extended version of a novel design technique which has the design method of the output feedback controller using dynamic compensator. The benefits of this scheme are demonstrated through the simulation and experimental results for proposed controller against chopper, gap sensor and acceleration sensor failures of electromagnetic suspension system.

• 반도체디스플레이기술학회지
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• 제7권2호
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• pp.55-58
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• 2008

The objective of the research is to design, manufacture and test a Mass Flow Controller(MFC) capable of measuring compressible fluid flows based on a "bucket and stop-watch"method. The basic principle is the measurement of time, where the time taken to fill and empty a bucket of known volume is measured. This method of flow measurement is a new concept when compared to a commercilized current mass flow controller. For the flow meter to be able to compete with established designs it not only must be comparable in cost and robustness, it must be very accurate and reliable as well. This device should be able to handle fluid flows in the range of 0.1ml/min to 10ml/min within an accuracy of ${\pm}$1%. A possible application for a device such as this is in electronics industry where arsenic gas is used in the production of silicon chips.