• Journal of the Korean Society of Propulsion Engineers
• /
• v.14 no.1
• /
• pp.40-47
• /
• 2010

In this study, basic research on the thrust control by controling oxidizer mass flow rate of a $GO_2$/PE hybrid rocket is presented. For this purpose, hybrid rocket system including oxidizer flow control system and data acquisition system was developed. To control oxidizer mass flow rate, we used needle valve with stepping motor which was controled by LabVIEW program. During the fundamental experiments, this system managed to follow the pre-programmed (20 N - 10 N - 20 N - 0 N) thrust level.

• Journal of Energy Engineering
• /
• v.10 no.3
• /
• pp.253-265
• /
• 2001

This paper investigates a PI control problem for the evaporator superheat, i.e., temperature difference between the two-phase region and the exit region of an evaporator, for multi-type air-conditioning/refrigeration system. Mathematical model describing the characteristics of compressor, condenser, evaporator, and electronic expansion valve are first derived. Then, two transfer function from the current input applied to an electronic expansion valve to the wall-temperatures of an evaporator tube at two-phase region and superheated region, respectively, are derived. The stability of the closed loop system with the PI controller designed it analyzed by using Nyquist stability criterion. Simulation results are provided.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.10a
• /
• pp.710-714
• /
• 2005

A dynamical analysis and PID control of a compressed gas expulsion system is performed. The purpose of this study is to develop a compressed gas discharging system and to verify the validity of the system. The electro-hydraulic servo valve is modeled as a 3th order transfer function to calculate flow force affecting expulsion valve is significantly considered. The friction force in the expulsion valve is considered as a nonliner model of stribeck effect. The dynamic characteristics of this system is examined by the computer simulation. The position control of the expulsion valve is performed by PID controller.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
• /
• v.45 no.3
• /
• pp.14-23
• /
• 2016

• Journal of Energy Engineering
• /
• v.25 no.1
• /
• pp.113-121
• /
• 2016

Polymer electrolyte membrane fuel cell(PEMFC) requires cooling system to maintain the proper operating temperature(about $65^{\circ}C{\sim}75^{\circ}C$) because the efficiency and power are affected by operating temperature. In order to retain the operating temperature of PEMFC, cooling system and coolant control logic are needed. Hardware-in-the-loop simulation(HILS) is one of effective methods to study and evaluate control algorithm. In this paper, the HILS system was designed to study the coolant control algorithm. The models of HILS system consisted of PEMFC, heat exchanger, and external environment associated with temperature. The hardwares in HILS system are 3-way valves, pumps, and a heat exchanger. The priority control and the control target temperature were investigated to improve the control performance using HILS. The 3-way valve in $1^{st}$ cooling circuit was selected as priority control target. The under limit value of $2^{nd}$ 3-way valve set as a function of PEMFC power and $2^{nd}$ circuit coolant temperature to correct temperature control performance. As a result, the temperature of PEMFC is stably controlled.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.5
• /
• pp.2594-2602
• /
• 2014

As environmental awareness increases, regulations on exhaust gas of automobile, which is a cause of air pollution, have been strengthened. In order to meet emission regulation, automobile companies and engine manufacturers have actively developed the related technologies. Because the emission control has become severe, the systems using electronic motor or solenoid valve for high precise control are needed. For this reason, it is required not only the optimization of composition of components for improving performance and efficiency of the system but also the development of optimal design technology of electronic control system by securing the designing and manufacturing technology of the components. In this paper, it is proposed the position characteristics for electronic EGR valve module through the applied control logic and experiment results.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.15 no.5
• /
• pp.35-47
• /
• 2011

Dynamic characteristics of a flow control valve, which plays an important role in thrust and O/F control of liquid rocket engines, have been analyzed by the AMESim simulator modeling. The speed control method was proposed for the control of the flow valve equipped with a BLDC motor. The experimental results demonstrated the feasibility of systematical application as well as the performance of the speed control method. Moreover, the speed control method for BLDC motor is much simpler than the P control method in complex flow systems. With the speed control method, the control flow characteristics were evaluated according to plunger shapes. Consequently, same plunger shape proved to be more efficient in the mixture ratio control operated by two flow valves. It was also shown that the appropriate modification of plunger shapes could reduce the mixture ratio perturbation by 0.5%.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2001.05a
• /
• pp.448-451
• /
• 2001

일반적으로 전기기기는 사람의 스위칭조작으로 작동이 되고 있다. 이를 개선하기 위하여 본 연구는 전기기기의 자동 스위칭과 홈네트워킹을 위한 제어용 임베디드 시스템을 설계하고, 제작하였다. 설계 제작한 제어 시스템은 PIC16F84에서 접근 센서의 입력 신호를 이용하여 전원 단속, 기기의 on/off를 수행하였으며, 내부의 상태를 감지하여 기기의 상태 표시용LED구동, 솔레노이드 밸브의 open/close 기능을 부여하였다. 본 임베디드 시스템은 통신 모듈을 구성하여 PIC의 기능을 강화하면 홈네트워킹용 시스템으로 발전할 수 있다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2011.11a
• /
• pp.929-932
• /
• 2011

We developed a valve actuator controller for thruster system. This thruster system has four actuators and the actuator use a BLDC motor. Controller was made based on system and control requirement. The controller is consist of power, control and Amp. The control module use a micro-controller which is TMS320F28335 of Texas Instruments. It works for digital PID control and CAN communication and system control. The amp module for three phase BLDC motor use IGBT.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.7C
• /
• pp.723-727
• /
• 2002

In this paper a new remote control system for operating indoor gas(LPG) range safely based on PLM(Power Line Modem) and telephone is developed because it would make disasters of properties and lives by user's carelessness or worker's bad installation, etc. The system includes the following elements: a telephone line interface system for user to call from the outdoors to the indoors, a communication system using the power line as a communication media, a system of cutting off gas and a alarm system.