• Journal of Electrical Engineering and Technology
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• v.8 no.5
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• pp.959-968
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• 2013

This paper presents a new approach with artificial immune system algorithm to solve the profit based unit commitment problem. The objective of this work is to find the optimal generation scheduling and to maximize the profit of generation companies (Gencos) when subjected to various constraints such as power balance, spinning reserve, minimum up/down time and ramp rate limits. The proposed hybrid method is developed through adaptive search which is inspired from artificial immune system and genetic algorithm to carry out profit maximization of generation companies. The effectiveness of the proposed approach has been tested for different Gencos consists of 3, 10 and 36 generating units and the results are compared with the existing methods.

• Bulletin of the Korean Mathematical Society
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• v.47 no.1
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• pp.29-37
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• 2010

We establish the existence of weak solutions in an infinite subsonic channel in the self-similar plane to the two-dimensional Burgers system. We consider a boundary value problem in a fixed domain such that a part of the domain is degenerate, and the system becomes a second order elliptic equation in the channel. The problem is motivated by the study of the weak shock reflection problem and 2-D Riemann problems. The two-dimensional Burgers system is obtained through an asymptotic reduction of the 2-D full Euler equations to study weak shock reflection by a ramp.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.1
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• pp.63-72
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• 1992

A tracking controller which can improve the performance of nonlinear electrohydraulic position control system is designed and implemented. The method is based on augmenting the system with integrators, obtaining the feedback control law which stabilizes the linear part of the original nonlinear system, and then reajusting the feedback gains using the deseribing funtion method to eliminate the limit cycle in the steady state. The proposed control law is implemented using OP amplifiers, and step and ramp response tests are carried out in the electrohydraulic servomechanism. The results show the improvement in both rransient and steady-state response.

• Proceedings of the KIEE Conference
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• 2002.06a
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• pp.142-145
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• 2002

This paper presents the electromagnetic field water treater system with the high performance for a good quality of water. The electromagnetic field water treater consists of a solion, a solion body. and a high voltage converter. The high voltage converter is controlled by PWM current controller. The high voltage converter of 13W is designed for an isolation operation ramp. an isolation current detector, and an over current protector. Using the high voltage PWM converter, the system with the proposed electromagnetic field water treater can be controlled easily. Simulation and experimental results show the effectiveness of the system strategy proposed for the scale rejection.

• Journal of the korean Society of Automotive Engineers
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• v.11 no.6
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• pp.68-79
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• 1989

Dynamic characteristics for an automotive V-belt CVT with centrifugal and torque-ramp actuators was investigated by bondgraph modeling method. Ten(10) state space equations for the V-belt CVT were developed from the constructed bondgraph model and linearized for perturbation at steady state. As simulation results, speed ratio versus time curves were obtained. It was found that as the ratio of the moment of inertia of the pulleys increased, the stability of the V-belt CVT system decreased. Change in the ratio of the spring constants caused the magnitude of the change of the speed ratio, but had little effect on the settling time of the system became faster and the stability of the system improved. However, the sensitivity of the speed ratio decreased with the increasing .betha.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.134-137
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• 1989

A digital controller for a discrete-data control system can take many forms. For example, they can be passive RC networks, general purpose digital computers, special purpose of mini-computer, and delay lines. With the recent advent of the microprocessor, its use as a digital controller is evident. This work discusses the hardware and software development of a microprocessor-based digital controller for a discrete-data control system. A second-order, Type 1 system is implemented on an analog computer; a Intel 80-286 microprocessor is used to implemented the controller; and, output response are obtained for step, ramp, and parabolic inputs. The results demonstrate that the microprocessor has potential as a digital controller. Finally, a brief discussion on the results indicate possible areas of improvement of the controller and future investigation.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.9
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• pp.1119-1125
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• 1999

In this paper, a decentralized multilevel-adaptive controller for a boiler-turbine system is designed by using multiple model adaptive method. It is applied to the drum type boiler-turbine system which is simplified from Boryung T/P #1,2 model. A linearlized model is decomposed into three subsystems by means of linear transformation. Then the DMC based on such subsystem is designed and a Multiple Model Adaptive Control(MMAC) scheme is applied for the purpose of the good tracking to variable load demands of the thermal power plant. The good performance of the designed controller is shown by simulations in various conditions that have the large step and ramp change of power demamd.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.1-6
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• 1991

This paper is concerned with the design of a robust tracking controller using a state observer on a robotic manipulator under the disturbance. The controller is designed to follow a step or ramp reference input without steady state error in the presence of a disturbance and a system parameter variation. In most cases, since all the state vectors are not measured, unmeasurable state vectors must be estimated or reconstructed. A reduced order observer is proposed to estimate unmeasurable state vectors of the non-linear system. Some problems are caused by the Coulomb friction, the disturbance, and the spring effect of a link between the drive motor and the manipulator arm. The state variables, directly measured and estimated by the reduced order observer, are fed back to the controller. When the robot system exhibits the 'limit cycle, the feedback gains initially obtained by optimal control theory are changed. As a result, the limit cycle is eliminated by the new controller gains,

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.500-500
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• 2000

In this paper, we deal wit,11 a simple tim varying feedforward compensator in order to decrease the amount of undershoots and overshoots on the step response. This compensator makes the step type input be a ramp input with saturation for 0 $\leq$ t < $\alpha$. It will be shown that the system with the feedforward compensator has small amount of undershoot and overshoot at the price of rise time. Also, provided the system properly stable, the influence of the design parameter $\alpha$ on the step response of the system with the feedforward compensator is investigated in the current paper.

• Journal of Electrical Engineering and Technology
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• v.13 no.4
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• pp.1494-1503
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• 2018

This paper proposes a novel probabilistic load flow model for power systems integrated with large-scale wind power, which considers the multi-time scale dispatching features. The ramp limitations of the units and the steady-state security constraints of the network have been comprehensively considered for the entire duration of the study period; thus, the coupling of the system operation states at different time sections has been taken into account. For each time section, the automatic generation control (AGC) strategy is considered, and all variations associated with the wind power and loads are compensated by all AGC units. Cumulants and the Gram-Charlier expansion are used to solve the proposed model. The effectiveness of the proposed method is validated using the modified IEEE RTS 24-bus system and the modified IEEE 118-bus system.