• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.53 no.6
• /
• pp.402-408
• /
• 2004

This paper proposes the novel V/f control method to improve the stability of a V/f controlled induction motor drive system. The conventional V/f control method used in the proposed V/f control method is a vector-based method that is slightly different from the existing conventional V/f control method. The proposed control method uses a dynamic current compensator to improve the stability of a V/f controlled induction motor drive system. This proposed method is easy to implement and completely eliminates the motor oscillation phenomenon causing the instability of a V/f controlled induction motor drive system, especially when the system is driven near the resonant frequency in steady-state with light load. Additionally, this paper analyzes theoretically the instability of a V/f controlled induction motor drive system and shows the validity of the Proposed V/f control method through simulation and experimental results.

• International Journal of Safety
• /
• v.3 no.1
• /
• pp.38-46
• /
• 2004

This paper introduces the software life-cycle V&V (verification and validation) tasks for the KNICS (Korea nuclear instrumentation and control system) project. The objectives of the V&V tasks are mainly to develop a programmable logic controller (PLC) for safety critical instrumentation and control (I&C) systems, and then to apply the PLC to developing the prototype of an engineered safety features-component control system (ESF-CCS) in nuclear power plants. As preparative works for the software V&V, various kinds of software plans and V&V task procedures have been developed according to the software life-cycle management. A number of software V&V tools have been adopted or developed to efficiently support the V&V tasks. The V&V techniques employed in this work include a checklist-based review and inspection, a requirement traceability analysis, formal verification, and life-cycle based software testing.

• 제어로봇시스템학회:학술대회논문집
• /
• 1987.10b
• /
• pp.218-222
• /
• 1987

The continuously variable transmission (C.V.T.) has been introduced for many years, however, the application of C.V.T. system has been used rather restrictively because of the problems such as reliability, durability, efficiency and, controllability. In this paper, some of the research trends about the control algorithms and the system design method involving C.V.T. is introduced. An engine is assumed in operation along the ideal operating line and it is also considered to be controlled independently to the C.V.T. system. The control simulation has been carried out to confirm it and also the operation performance of the system is investigated.

• Journal of information and communication convergence engineering
• /
• v.19 no.4
• /
• pp.214-220
• /
• 2021

In this study, we constructed several scenarios that are required for LED lighting, and we designed and implemented an LED lighting control system to operate these scenarios to confirm their behavior. An LED lighting control system is a hybrid control board that is designed by combining LED controllers and SMPS, consisting of an AC/DC power supply part that converts AC 220 V into DC 12 V, and a drive and control part that controls the scenario and color of the LED module. Conventional LED light controllers have an input power of DC 12 V, so when using the input AC 220 V, the SMPS must be connected to the LED light controller. To eliminate this inconvenience, a hybrid LED lighting control system was configured to combine LED lighting controllers and SMPS into one control system. Furthermore, we designed a control system to represent the most appropriate color according to the input of the distance and illumination using a fuzzy control system to conduct computer simulations.

• Smart Media Journal
• /
• v.12 no.5
• /
• pp.73-80
• /
• 2023

Recently, intelligent control systems are developing rapidly in various application fields, and methods for utilizing technologies such as deep learning, IoT, and cloud computing for intelligent control systems are being studied. An important technology in an intelligent control system is recognizing and tracking objects in images. However, existing multi-object tracking technology has problems in accuracy and speed. In this paper, a real-time intelligent control system was implemented using YOLO v5 and YOLO v6 based on a one-shot architecture that increases the accuracy of object tracking and enables fast and accurate tracking even when objects overlap each other or when there are many objects belonging to the same class. The experiment was evaluated by comparing YOLO v5 and YOLO v6. As a result of the experiment, the YOLO v6 model shows performance suitable for the intelligent control system.

• Journal of Mechanical Science and Technology
• /
• v.15 no.1
• /
• pp.66-80
• /
• 2001

In brake systems, a proportioning valve(P. V), which reduces the brake line pressure on each wheel cylinder for the anti-locking of rear wheels, is closely related to the safety of vehicles. However, it is impossible for current P. V. s to completely control brake line pressure because, mechanically, it is an open loop control system. In this paper we describe an electronic brake force distribution system using a direct adaptive fuzzy controller in order to completely control brake line pressure using a closed loop control system. The objective of the electronic brake force distribution system is to change the cut-in-pressure and the valve slop of the P. V in order to obtain better performance of the brake system than with mechanical systems.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.19 no.2
• /
• pp.73-80
• /
• 2015

It had been almost a half century since Apollo Mission was ended. However, in these days, a lot of researches are being conducted for restoration and making improvements in technologies used in Saturn V rocket's development. This study reviews the first stage of Saturn V rocket(S-IC), from development history to technologies in various subsystems such as engine purge system, POGO suppression system, hydraulic and pneumatic control system, propellant dispersion system, telemetry system and retrorocket system. Understandings of S-IC stage's operation systems would be helpful in understanding of launch vehicle system and reduction of time and cost in future development process.

• Proceedings of the Korea Association of Crystal Growth Conference
• /
• 1999.06a
• /
• pp.361-369
• /
• 1999

New method of control based upon a physical model of the Stepanov growth technique has been developed. The controller keeps the system stable and completely denies operator's interference into the process. The system demonstrates very reliable results under commercial production of shaped sapphire crystals.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.9 no.4
• /
• pp.437-440
• /
• 1999

New method of control based upon a physical model of the Stepanov growth technique has been developed. The controller keeps the system stable and completely denies operator's interference into the process. The system demonstrates very reliable results under commercial production of shaped sapphire crystals.

• Proceedings of the KIPE Conference
• /
• 2001.10a
• /
• pp.466-469
• /
• 2001

In this paper, closed loop V/f control of induction motor has been implemented by the estimated speed. Closed loop V/f control improve the performance of induction motor drive system at low speed compared to open loop V/f control. However, closed loop V/f control need speed sensor. By using the estimated speed, closed loop V/f control is possible without speed sensor. Rotor speed is calculated from the difference between synchronous frequency and slip angular frequency. 3-phase voltage reference is obtained from synchronous frequency. And the PWM technique using space vector PWM is applied in this scheme. In the space vector PWM, effective time of 3-phase voltage reference is used to simplify the calculation of effective voltage time. This scheme is simple to implement and one chip microprocessor was used in experimental system.