• Proceedings of the KIEE Conference
• /
• 1993.11a
• /
• pp.35-37
• /
• 1993

This paper shows that the presence of constant impedance loads and induction motors in power system's loading contents can lead to transient voltage instabilities during normal system manipulations such as switchings. The abnormal induction motor characteristics during system transients which initiate the voltage instabilities are illustrated. The influence of motor and network parameters, such as motor inertia mechanical load quantity and nature on the severity of the voltage instability are studied.

• Proceedings of the KIEE Conference
• /
• 1993.11a
• /
• pp.66-69
• /
• 1993

Now a days, the inverter fed induction motors are being widely used. In this case, many harmonic voltages cause a additional effect on the characteristics of induction motor. Several characteristics calculation methods have been introduced. But it needs tedious experiments for designer to apply these methods to induction motor because these methods need measurement and test results. This paper presents characteristics calculation method which don't need measurement and test results. And this paper shows that the simulation results agree well with values obtained by actual load test.

• Proceedings of the KIEE Conference
• /
• 1993.11a
• /
• pp.160-162
• /
• 1993

This paper proposes a new converter for switched reluctance motors using a Boost converter in conjunction with a Buck converter. The proposed converter has a unity power factor(hereafter referred to an UPF) in the ac input regardless of the load variations. Moreover, compared to the conventional converter topologies, the total system efficiency is improved by introducing choppingless voltage control methods in the machine side converter and an energy recovery snubber in the pre-voltage regulation stage, respectively.

• Proceedings of the KIEE Conference
• /
• 1992.07a
• /
• pp.391-393
• /
• 1992

This paper proposes an adaptive control system using a 80286 microprocessor-based system and DC servo motors for the control of flexible joint manipulator. In this paper, we construct the controller based on a singular perturbation strategy damping out the elastic oscillations at the joints. we added to the controller the compensator for damping the joint and the term for decreasing the position error between the actuator and the link in order to improve the asymptotical convergence of the position of the link. It is shown that the implementation of this control algorithm can be practical.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.53 no.1
• /
• pp.14-21
• /
• 2004

Most adjustable-speed drives (ASDs) designed to operate low voltage induction motors incorporate voltage-source inverters (VSIs), which create motor voltages at high switching frequencies. The motor leads used to connect an ASD to a motor can behave like transmission lines for voltage pulses, which can be reflected at the motor terminals. The resulting oscillatory transient, known as the long-lead effect, can stress and consequently degrade the stator insulation system of a motor. This paper describes the results of tests to 1) determine the correlation between peak motor voltage and the length of motor leads and 2) determine the correlation between peak motor voltage and the switching frequency of the ASD Insulation failures like this usually are caused by voltage surges. Voltage surges are often the result of switching power circuits, lightning strikes, capacitor discharges and solid-state power devices.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.65 no.1
• /
• pp.1-6
• /
• 2016

Recently, proportion of the induction motor load is gradually increased. When a contingency in the power systems, it has been discovered phenomenon that the voltage is delayed recover caused mechanical characteristics of the induction motor load. It can be a serious impact on the voltage stability of the power system considering induction motor load. The scheme to mitigate this phenomenon tripping off the motors to prevent voltage drop and delayed voltage recovery on the load demand side. Fault induced delayed voltage recovery phenomenon is caused by stalling of small induction motor load in transmission level contingencies. In this paper, fault induced delayed voltage recovery phenomenon mitigation method implementation under voltage load shedding on the korean power system considering induction motor load.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.64 no.2
• /
• pp.289-296
• /
• 2015

In this paper, we propose the nonlinear control based on singular perturbation theory for position tracking and yaw regulation of planar motor. Singular perturbation theory is characterized by the existence of slow and fast transients in the system dynamics. The proposed method consists of auxiliary control to decouple error dynamics. We develop model reduction with control input. Also, we derIve decoupled error dynamics with auxiliary input. The controller is designed in order to guarantee the desired position and yaw regulation without current feedback or estimation. Simulation results validate the effect of proposed method.

• Proceedings of the IEEK Conference
• /
• 2009.05a
• /
• pp.153-155
• /
• 2009

Cleaning robot system consists of four parts; navigation system for moving of robot, cleaning system, power system, and main system with cleaning algorithm. Navigation system is the most expensive part because it has motors and sensors which is high price. Navigation system is also essential to service robot system, but user should buy two systems which are service robot system and cleaning robot system. If it is possible to share navigation system, user can save money. In this paper, we design the cleaning robot system based on modular architecture.

• 유체기계공업학회:학술대회논문집
• /
• 2001.11a
• /
• pp.367-372
• /
• 2001

A fuel cell is an electrochemical energy conversion device tint converts hydrogen and oxygen into electricity and heat for hot water and heating room A fuel cell provides a DC voltage tint can be used to power motors, lights or any number if electrical appliances. There are several different types if fuel cells, each using a different chemistry. Some types if fuel cells show promise for use in DC (distributed generation) because fuel cell is very clean and efficient energy device. CETI (Clean Energy Technologies, Inc.) is developing PEMFC and DMFC for residential power generation, portable and battery. It is anticipated tint RPG is advantageous over current power generation by utility In terms if economics assuming the lifetime of major components is at least five years.

• 유체기계공업학회:학술대회논문집
• /
• 2006.08a
• /
• pp.245-248
• /
• 2006

Hybrid propulsion systems provide many advantages in terms of stable operation and safety. However, classical hybrid rocket motors have lower fuel regression rate and combustion efficiency compared to solid propellant rocket motor. Accordingly, the recent research efforts are focused on the improvement of engine efficiency and regression rate in the hybrid rocket engine. The present study has numerically investigated the combustion processes in the hybrid rocket engine. The turbulent combustion is represented by the flamelet model and Low Reynolds number $k-{\varepsilon}$ turbulent model is employed to reduce the uncertainties for convective heat transfer near solid fuel surface having strong blowing effect. Based on numerical results, the detailed discussions have been made for the effects of oxygen injection methods and oxygen injection flow rate on flame structure and regression rate in the vortex hybrid rocket engines