• Title/Summary/Keyword: Steady-state error

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Improved reactor regulating system logical architecture using genetic algorithm

  • Shim, Hyo-Sub;Jung, Jae-Chun
    • Nuclear Engineering and Technology
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    • v.49 no.8
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    • pp.1696-1710
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    • 2017
  • An improved Reactor Regulating System (RRS) logic architecture, which is combined with genetic algorithm (GA), is implemented in this work. It is devised to provide an optimal solution to the current RRS. The current system works desirably and has contributed to safe and stable nuclear power plant operation. However, during the ascent and descent section of the reactor power, the RRS output reveals a relatively high steady-state error, and the output also carries a considerable level of overshoot. In an attempt to consolidate conservatism and minimize the error, this work proposes to apply GA to RRS and suggests reconfiguring the system. Prior to the use of GA, reverse engineering is implemented to build a Simulink-based RRS model. Reengineering is followed to produce a newly configured RRS to generate an output that has a reduced steady-state error and diminished overshoot level. A full-scope APR1400 simulator is used to examine the dynamic behaviors of RRS and to build the RRS Simulink model.

Fuzzy control system design by data clustering in the input-output subspaces (입출력 부공간에서의 데이터 클러스터링에 의한 퍼지제어 시스템 설계)

  • 김민수;공성곤
    • Journal of the Korean Institute of Telematics and Electronics S
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    • v.34S no.12
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    • pp.30-40
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    • 1997
  • This paper presents a design method of fuzzy control systems by clustering the data in the subspace of the input-output produyct space. In the case of servo control, most input-outputdata are concentrated in thye steady-state region, and the the clustering will result in only steady-state fuzzy rules. To overcome this problem, we divide the input-output product space into some subspaces according to the state of input variables. The fuzzy control system designed by the subspace clustering showed good transient response and smaller steady-state error, which is comparable with the reference fuzzy system.

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Novel Current Controlled PWM-VSC Converter Using Current Error Vector Control (전류오차 백터 제어방식에 의한 새로운 형태의 전류 제어 PWM 전압형 정류기)

  • 박민호;최재호
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.38 no.4
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    • pp.261-268
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    • 1989
  • A novel current controlled PWM voltage source type converter and control strategy is proposed that is able to draw nearly sinusoidal current at unity power factor from three phase power lines. Current error vector control scheme is used which has two operating states : low harmonic current content state and quick current response state. The state is changed according to the current error to optimize the steady state and transient state performances. To regulate the dc oupput voltage, the magnitude of the reference current is determined by a controller dc voltage error. The ac input power factor can be controlled with unity, and even leading or lagging by adjusting the relative position of the reference current with respect to the supply voltage.

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Tracking Control of IPMSM using the Active Disturbance Rejection Control (매입형 영구자석 동기전동기의 능동외란제거제어를 이용한 추종제어)

  • Jeon, Yong-Ho;Chae, Seong-Byeong
    • The Journal of the Korea institute of electronic communication sciences
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    • v.17 no.5
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    • pp.859-866
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    • 2022
  • Active disturbance rejection control is a method in which the disturbance is removed from the controller by estimating the state variable using the Luenberger observer. The Luenberger observer is estimated by defining a nonlinear term including disturbance with constant characteristics in a steady state as a state variable. It can be shown that the speed tracking performance is improved by compensating the estimated state variable to the PI controller and the IP controller. The disturbance removal performance of the tracking control can be confirmed by observing that the estimated state error is within 1.9 [%] in the case of load fluctuation and the steady-state state tracking error converges to zero.

Double Vector Based Model Predictive Torque Control for SPMSM Drives with Improved Steady-State Performance

  • Zhang, Xiaoguang;He, Yikang;Hou, Benshuai
    • Journal of Power Electronics
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    • v.18 no.5
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    • pp.1398-1408
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    • 2018
  • In order to further improve the steady-state control performance of model predictive torque control (MPTC), a double-vector-based model predictive torque control without a weighting factor is proposed in this paper. The extended voltage vectors synthesized by two basic voltage vectors are used to increase the number of feasible voltage vectors. Therefore, the control precision of the torque and the stator flux along with the steady-state performance can be improved. To avoid testing all of the feasible voltage vectors, the solution of deadbeat torque control is calculated to predict the reference voltage vector. Thus, the candidate voltage vectors, which need to be evaluated by a cost function, can be reduced based on the sector position of the predicted reference voltage vector. Furthermore, a cost function, which only includes a reference voltage tracking error, is designed to eliminate the weighting factor. Moreover, two voltage vectors are applied during one control period, and their durations are calculated based on the principle of reference voltage tracking error minimization. Finally, the proposed method is tested by simulations and experiments.

A Hybrid Error Generation Algorithm Using Confidence Intervals on Signal Constellation (신호 성상도 상의 신뢰구간을 활용한 하이브리드 오차 발생 알고리즘)

  • Oh, Kil Nam
    • Journal of the Institute of Electronics and Information Engineers
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    • v.51 no.11
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    • pp.19-25
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    • 2014
  • For effective updating a blind equalizer, we propose the adaptive algorithm having faster convergence speed required for initial equalization and satisfying low error level required in steady-state while having a gradual and reversible switching characteristics between initial stage and steady-state. The proposed method presents three criteria to distinguish the state of equalized signal, according to the criteria, differently updates the equalizer by using the hybrid error generation algorithm generating one of the three errors. Wherein as the criteria to determine the state of the equalized signal the confidence intervals on the signal constellation are used, an error is generated alternatively according to the confidence interval where equalizer output lies, and the equalizer is updated by, we got convergence quickly and to lower error level. In order to verify the usefulness of the proposed idea, simulation results were compared to the performance of conventional methods.

Acquisition Behavior of a Class of Digital Phase-Locked Loops (Digital Phase-Locked Loops의 위상 포착 관정에 관한 연구)

  • 안종구;은종관
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.19 no.5
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    • pp.55-67
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    • 1982
  • In this Paper new results relating to the acquisition behavior of a class of first-and secondorder digital phase-locked loops (DPLL) originally proposed by Reddy and Cupta are presented in the absence of noise. It has been found that the number of quantization levels L and the number of phase error states N play important roles in acquisition. For a given L-level quantizer, as N increases, the acquisition time increases, and the lock range decreases. However, the deviation of the steady state phase error decreases in this case. When L increases, the acquisition time decreases, and the lock range increases. However, variation of L affects little for the steady state phase error. In addition, the effects of a loop filter on acquisition have also been considered. One can get smaller acquisition time and larger lock range as the filter parameter value becomes larger. However, deviation of the steady state phase error increases in that case. Analytical results have been verified by computer simulation.

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A P-Parallel Controller Design based on P-Control Ramp Response in Machine Tool (비례제어 경사응답에 기반한 공작기계의 비례-병렬 제어기 설계)

  • Gil, Hyeong-Gyeun;Lee, Gun-Bok
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.780-785
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    • 2004
  • The work presented here deals with controller design by graphical method based on proportional control ramp response. The design aims at the improvement of transient response, disturbance rejection capability, steady-state error reduction with stability preservation. The first step is to generate tracking-error curve with proportional control only and decide the added error signal shape on the error curve. The effectiveness of the proposed controller is confirmed through the simulation and experiment.

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Estimation and Demonstration Test Plan for Availability with Weibull Lifetime and Lognormal Repair Time (와이블 수명분포와 대수정규 수리시간분포 하에서 가용도의 추정과 실증시험계획)

  • Seo, Sun-Keun
    • Journal of Applied Reliability
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    • v.14 no.1
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    • pp.1-9
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    • 2014
  • One important measure of performance for a repairable system is steady-state availability. In this paper, a method to estimate and establish confidence interval for the steady-state availability under Weibull lifetime and lognormal repair time distributions is proposed. Also, bias and mean squared error of a point estimator for an availability are investigated. In addition, a procedure to derive the sample size and critical value for availability demonstration test is presented and illustrated with a numerical example.

A Mathematical Model on the Absorption Rate of Carbon-Dioxide in Mixed Gas During the Transient State of Rotary Type Absorbers (과도상태의 회전형 흡수기에서 혼합기체 중 이산화탄소 흡수량 계산 모델)

  • Paik, Hyun-Jong
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.26 no.12
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    • pp.1729-1737
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    • 2002
  • A mathematical model for the prediction of carbon-dioxide absorption rate during the transient state of rotary type absorber is developed. The rotary type absorber operates using a fast rotating porous structure and clean water. The model for the transient state rotary type absorbers is based on the steady state model of packed tower absorber. The paper manipulates the operating data of an arbitrary quasi-steady state condition of rotary type absorber for the determination of the coefficients involved in the model developed. The prediction accuracy is evaluated from the measured data of rotary type absorber operated under fast transient state. The measured data include the mole fraction of carbon dioxide in mixed gas and the pressure of absorber. The relative error in carbon dioxide prediction is estimated to be 20% at maximum. The model is successfully applied for the prediction of the behavior of a closed cycle diesel engine.