• International journal of advanced smart convergence
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• 제12권3호
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• pp.1-12
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• 2023

A public address (PA) system installed in a building is a system that delivers alerts, announcements, instructions, etc. in an emergency or disaster situation. As for the products used in PA systems, with the development of information and communication technology, PA products with various functions have been introduced to the market. PA systems recently launched in the market may be connected through a single network to enable efficient management and operation, or use voice recognition technology to deliver quick information in case of an emergency. In addition, a system capable of locating a user inside a building using a location-based service and guiding or responding to a safe area in the event of an emergency is being launched on the market. However, the new PA systems currently on the market add some functions to the existing PA system configuration to make system operation more convenient, but they do not change the complex PA system configuration to reduce facility costs, maintenance, and management costs. In this paper, we propose a novel PA system configuration for buildings using audio networks and control hierarchy over peer-to-peer (Anchor) technology based on audio over IP (AoIP), which simplifies the complex PA system configuration and enables convenient operation and management. As a result of the study, through the emergency signal processing algorithm, fire broadcasting was made possible according to the detection of the existence of a fire signal in the Anchor system. In addition, the control device of the PA system was replaced with software to reduce the equipment installation cost, and the PA system configuration was simplified. In the future, it is expected that the PA system using Anchor technology will become the standard for PA facilities.

• Journal of Advanced Marine Engineering and Technology
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• 제40권7호
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• pp.613-621
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• 2016

본 논문에서는 현장 및 원격지에서 해양플랜트 및 선박의 내부 IP기반 네트워크 장비의 운용, 설정과 원격지 통제 지원을 위하여 네트워크 장비, CCTV, PAGA, IP-PBX, Legacy를 연동하고 원격지에서 장비의 상태, 작업 상황, 알림 등의 모니터링과 제어가 가능한 네트워크 장비 통합 관리 시스템의 운영 프로그램을 구현하였다. 개발된 운용 프로그램을 위성지구국과 운항중 선박에 적용하여 선육간 통신 구간에서의 데이터 유실 및 송수신 지연에 대한 성능을 시험한 결과 FBB, MVSAT 환경에서 네트워크 장비, PAGA, IP-PBX, Legacy의 실시간 모니터링 및 제어와 CCTV의 제어 기능이 정상적으로 동작함을 확인하였다. 단 데이터량이 비교적 큰 CCTV 영상 수신과 음성 데이터의 송수신은 다소 지연되어 데이터의 실시간 송수신을 위한 데이터 압축 및 변환 기술 개발이 필요함을 확인하였다.

• International Journal of Control, Automation, and Systems
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• 제4권1호
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• pp.113-123
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• 2006

In this paper, an improved direct torque control (DTC) method for sensorless matrix converter drives is proposed which enables to minimize torque ripple, to obtain unity input power factor, and to achieve good sensorless speed-control performance in the low speed operation, while maintaining constant switching frequency and fast torque dynamics. It is possible to combine the advantages of matrix converters with the advantages of the DTC strategy using space vector modulation and a flux deadbeat controller. To overcome the phase current distortion by the non-linearity of a matrix converter drive, the simple non-linearity compensation method using PQR power theory are presented in the proposed scheme. Experimental results are shown to illustrate the feasibility of the proposed strategy.

• 산업기술연구
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• 제29권B호
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• pp.165-171
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• 2009

This paper proposes a sensorless control method of BLDC motors using line-to-line back-EMFs. Typical sensorless control methods have various problems such as the difficulty in operation at low speed and difficulties in application and so forth. However, the control method using line-to-line back-EMFs that this paper proposes solved not only such problems but also problems of noise and difficulty of commutation detection. The method is to divide line-to-line back EMF into the constant. With 550[W] BLDC motor driving system, simulations and experiments have been carried out for the verification of the proposed control method.

• 한국정밀공학회지
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• 제12권12호
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• pp.19-29
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• 1995

The basic technology for a production system represented by design, machining, assembly, and inspection, is machining technology such as CNC machine tools. etc. Direct Numerical Control, that effeciently manages NC programs is developing into Distributed Numerical Control that increases the utilization of the machining cell. It has the ability of monitoring and control, in real time, for CNC and periperial equipment. In this study, we develop a Distributed Numerical Control system that has real time and multitasking operation capability for the machining cell with various CNC's. With the consideration of economy, generalization and extension, the system is interfaced with CNC machine tools and periperial device using RS-485 network and RS-232C communication methods.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 제3회 압연심포지엄 논문집 압연기술의 미래개척 (Exploitation of Future Rolling Technologies)
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• pp.423-428
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• 1999

A high precision hot strip width control method has been developed in this study by applying interstand looper tension measuring system at finishing mill stands. As with deviation of hot rolled steel strip is closely related to abnormal increase in the interstand strip tension, on-line measuring device of looped tension and data analyzing system was developed in this study. To determine dominant factors that will cause local width shortage, the logged data sets of bar width, bar thickness, looper tension, and strip thickness along the strip length were correlated with the data set of strip width change. With the result of the correlation analysis, existing sequence control logic and parameters for looper actuator were modified for strip width quality and the gains of the looper control were refined for the stable operation during the full passage of rolled strip. The on-line tension measurement and tension feedback control for looper system improved strip travelling stability and reduced strip width deviation in the srip top end region.

• Journal of Electrical Engineering and Technology
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• 제8권1호
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• pp.110-117
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• 2013

Maximum Torque Per Amp (MTPA) control for induction motor drives seeks to achieve a desired torque with the minimum possible stator current. This is favorable in terms of inverter operation and nearly optimal in terms of motor efficiency. However, rotor resistance variation can cause significant performance degradation. This work demonstrates that existing MTPA controls perform sub-optimally as temperature varies. An adaptive MTPA control strategy is proposed that always achieves optimal performance without exhibiting hunting phenomenon regardless of rotor temperature. The proposed control is experimentally shown to accurately achieve the desired torque.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.845-847
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• 2015

A suspending force control based on fuzzy logic control is proposed to apply on a novel hybrid bearingless switched reluctance motor(BLSRM) which has separated torque and suspending force pole. Due to the unique structure, the suspending force control system can be easily decoupled from torque control system. In this paper, two fuzzy controller targeted at x-axis direction and y-axis direction are adopted to maintain the shaft at center position, which is very necessary for stable operation of BLSRM. By replacing the traditional PI block with modified fuzzy logic controller, the suspending system can behave a good performance, and the proposed scheme can be verified by simulation results.

• 수산해양기술연구
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• 제55권4호
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• pp.402-410
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• 2019

This paper deals with the disturbance observer (DOB) based sliding mode control (SMC) for a DC motor to control motor rotating speed precisely and to ensure strong robustness against disturbance including load torque and parameter variation. The reason of steady state error in speed on conventional SMC without DOB is analyzed in detail. Especially, the suggested DOB is designed to prevent measuring noise and harmonics caused by derivative operation on rotating speed. The control performance of the DOB based SMC is evaluated by the various simulations. The simulation results showed that the DOB based SMC had more robust performance than the SMC system without DOB. Especially, precise speed control was possible even though motor parameter variation and load torque was added to the system.

• 산업기술연구
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• 제20권B호
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• pp.189-194
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• 2000

In this paper, we present a BLDC Motor control for needle positioning and velocity control in the industrial sewing machine. In the industrial sewing machine, the fast acceleration control is needed, especially for a person who has a skill in operation of sewing machine for more products. And it is also needed to have a less noise and vibration. But the system which is made in a low price has no feedback system for a current control. Therefore we propose the method of velocity pattern that has an acceleration of velocity and Anti-windup algorithm. By the experiment, we confirmed that these manner have a good performance for low noise, low vibration and fast acceleration in the industrial sewing machine.