• Title, Summary, Keyword: variable structure system

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The Generator Excitation Control Based on the Quasi-sliding Mode Pseudo-variable Structure Control

  • Hu, Jian;Fu, Lijun
    • Journal of Electrical Engineering and Technology
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    • v.13 no.4
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    • pp.1474-1482
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    • 2018
  • As an essential means of generator voltage regulation, excitation control plays an important role in controlling the stability of the power system. Therefore, the reasonable design of an excitation controller can help improve the system stability. In order to raise the robustness of the generator exciting system under outside interference and parametric perturbation and eliminate chattering in the sliding mode control, this paper presents a generator excitation control based on the quasi-sliding mode pseudo-variable structure control. A mathematical model of the synchronous generator is established by selecting its power, speed and voltage deviation as state variables. Then, according to the existing conditions of the quasi-sliding mode, a quasi-sliding mode pseudo-variable structure controller is designed, and the parameters of the controller are obtained with the method of pole configuration. Simulations show that compared with the existing methods, the proposed method is not only useful for accurate voltage regulation, but also beneficial to improving the robustness of the system at a time when perturbance happens in the system.

Variable structure control for matched and unmatched uncertainty with quadratic criterion

  • Rhee, Bond-Jae;Park, Ju-Hyun;Won, Sangchul
    • 제어로봇시스템학회:학술대회논문집
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    • pp.458-463
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    • 1997
  • In this paper, we propose a variable structure control approach for the system with matched and unmatched uncertainty. By using time-varying sliding mode, the reaching mode is removed, and the design methodology represents a realistic design approach with quadratic criterion for systems incorporating both matched and unmatched uncertainties. The criterion contains states and linear part of input for all time. The practical application of the control strategy is presented in the design of a stability augmentation system for an aircraft is presented.

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Variable Structure Controller for Linear Time-Varying Sampled-Data Systems with Disturbances (외란을 갖는 선형 시변 샘플링된 시스템에 대한 가변구조제어기)

  • Park Kang-Bak
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.51 no.12
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    • pp.556-561
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    • 2002
  • In this paper, a discrete-time variable structure controller for linear time-varying sampled-data systems with disturbances is proposed. The proposed method guarantees that the system state if globally uniformly ultimately bounded (G.U.U.B), and the ultimate bound is shown to be the order of T, O(T), where T is a sampling period.

An Improved Estimate of the Asymptotic Stability Region for the Uncertain Variable Structure Systems with Bounded Control (크기가 제한된 입력을 갖는 가변구조제어 시스템을 위한 개선된 안정 영역 추정값)

  • Choi Han Ho
    • Journal of Institute of Control, Robotics and Systems
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    • v.11 no.6
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    • pp.492-495
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    • 2005
  • This paper deals with the problem of estimating the asymptotic stability region(ASR) of uncertain variable structure systems with bounded control. Using linear matrix inequalities(LMIs) we estimate the ASR and we show the exponential stability of the closed-loop control system in the estimated ASR. We show that our estimate is always better than the estimate of [3].

Tracking Control of Variable Structure System with a New Variable Boundary Layer (새로운 가변 경계층을 갖는 가변 구조 제어 시스템의 추적 제어)

  • Lee, Hui-Jin;Kim, Eun-Tae;Kim, Dong-Yeon
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.37 no.3
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    • pp.19-32
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    • 2000
  • This paper suggests the variable structure controller with a new variable boundary layer for the accurate tracking control of the variable structure systems. Up to now, variable structure controller (VSC) applying the variable boundary layer did not remove chattering from an arbitrary initial state of the system trajectory because VSC has the limited initial state according to the fixed sliding surface. But, by using the linear time-varying sliding surfaces, the scheme has the robustness against chattering from all states. The suggested method can be applied to the second-order nonlinear systems with parameter uncertainty and extraneous disturbances, and has better tracking performance than the conventional method. To demonstrate the advantages of the proposed algorithm, it is applied to a two-link manipulator.

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Implementations of the variable structure control system using neural networks (신경회로망을 이용한 가변 구조 제어 시스템의 구현)

  • Yang, Oh;Yang, Hai-Won
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.33B no.8
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    • pp.124-133
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    • 1996
  • This paper presents the implementation of variable structure control system for a linear or nonlinear system using neural networks. The overall control system consists of neural network controller and a reaching mode controller. While the former approximates the equivalent control input on the sliding surface, the latter is used to bring the entire system trajectories toward the sliding surface. No supervised learning procedures are needed and the weights of the neural network are tuned on-line automatically. The neural netowrk-based variable structure control system is applied to a nonlinare unstable inverted pendulum system through computer simulations, and implemented using a microcomputer (80486-50MHz) and applied to the DC servomotor position control system. Simulation and experimental results show the expected approximation sliding property is occurred. The proposed controller is compared with a PID controller and shows better performance than the PID controller in abrupt plant parameter change.

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Digital variable structure control of a hot-water heating control system with long dead time (긴 지연시간을 갖는 온수난방 제어시스템의 디지틀 가변구조제어)

  • 안병천;장효환
    • 제어로봇시스템학회:학술대회논문집
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    • pp.232-237
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    • 1991
  • Digital Variable Structure Controller(DVSC) is proposed to control variable speed recirculating pump for hot-water heating control system. In this study, nonlinear sliding line is used beyond output error boundary layer and PID sliding line is used within the layer. For long dead time compensation, constraint is added to Smith predictor algorithm. Steady state error is eliminated by using the proposed sliding line in spite of heating load change. By decreasing sampling time, good sliding motion is yielded but system output noise bv flow dynamics is amplified.

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Output feedback semiglobal stabilization for a nonlinear system (광범위한 안정 영역을 갖는 출력만을 이용한 제어기 설계)

  • 오성록
    • Journal of the Korean Institute of Telematics and Electronics S
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    • v.34S no.9
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    • pp.60-66
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    • 1997
  • WE consider the stabilization of a class of multivariable nonlinear system using variable structure output feedback control. A high-gain observer is used to estimate state variable while rejecting the effect of the disturbances. We design a globally bounded output feedback variable structure controller that semi-globally stabilize the closed-loop system, while state variables do not exhibit a peaking.

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High-Precision Direct-Operated Relief Valve with a Variable Elasticity Spring (변탄성 스프링을 이용한 고정밀 직동형 릴리프 밸브)

  • Kim, SungDong
    • Journal of Drive and Control
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    • v.17 no.4
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    • pp.87-96
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    • 2020
  • In this study, a variable elasticity spring was applied to improve the pressure control precision of conventional relief valves. The equilibrium equation of the forces acting on the valve poppet was derived; it is demonstrated that matching the elastic rate of the pressure-adjusting coil spring to the equivalent elastic rate of the flow force improved the pressure override. The procedures that were used to design the variable elasticity spring are presented, and some applications of the variable elasticity spring are also introduced. Computer simulations were used to analyze three cases: a poppet-closed flow force structure, a poppet-open flow force structure with a constant elasticity spring, and a structure containing a variable elasticity spring. It is confirmed that the pressure control precision of the relief valve can be significantly improved upon by applying a variable elasticity spring to the poppet-open flow force structure.

Mortion Control of DC Servo System Using Variable Structure Control (가변구조제어를 응용한 직류서보 제어계의 위치제어에 관한 연구)

  • Hong, S.I.;Bae, G.H.;Song, J.Y.
    • Proceedings of the KIEE Conference
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    • pp.742-744
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    • 1995
  • In position control system using variable structure control, the velocity of control object is controlled to approach the desired specified velocity patterns, and eventually the position of control object is correctly at reference position. Here, this intention can be success by means of variable structure control. In this paper, the PI velocity feedback control is also used sliding mode controller. The design of position controller under specified velocity profiles in variable structure control's constraints is studied.

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