• 제목/요약/키워드: Dead-Time Control

검색결과 332건 처리시간 0.027초

유도전동기의 강인 속도 제어기에 관한 연구 (A Study on the Robust Speed Controller of Induction Motor)

  • 변황우
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1997년도 하계학술대회 논문집 B
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    • pp.612-615
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    • 1997
  • In this paper, a robust speed controller considering the effect of uncertainty (plant parameter variation. external load disturbance. unmodeled and nonlinear dynamics etc..) for induction motor is proposed. Firstly. the dynamic model at nominal case of induction motor is estimated. Based on the estimated model. the IPSC ( Integral - Proportional Speed Controller) is designed. Then a DTRC (Dead-time Robust Controller) combining DTC ( Dead-time Compensator) & SRC (Simple Robust Controller) is designed to reduce the effects of parameter variation and external disturbance. Some simulated results are provided to demonstrate the effectiveness of the proposed controller.

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단상 PV 인버터용 온-라인 데드타임 보상기 연구 (A New On-Line Dead-Time Compensator for Single-Phase PV Inverter)

  • 부우충기엔;차한주
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2010년도 하계학술대회 논문집
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    • pp.216-217
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    • 2010
  • This paper presents a new software-based on-line dead-time compensation technique for single-phase grid-connected photovoltaic (PV) inverter system. To improve the mitigation of dead-time effect around the zero-crossing point of phase current, a selective harmonic elimination of instantaneous feedback current is used as an additional part of conventional current control scheme. Simulation and experimental results are shown to verify the effectiveness of proposed compensation method in the grid-connected power distributed generation systems.

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지역난방 공동주택 시스템에서 Smith Predictor 제어기 적용성 연구 (Strategy to Maintain the Smith Predictor Controller in the District Heating System for Apartment Buildings)

  • 정상훈;문연진;하재순;조성환
    • 대한설비공학회:학술대회논문집
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    • 대한설비공학회 2009년도 하계학술발표대회 논문집
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    • pp.1025-1030
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    • 2009
  • It is known that the classical tuning formula for typical PID controllers in general provides unsatisfactory results for industrial plants where the time delay exceeds the dominant lag time. For this reason, alternative strategies have been studied in order to cope with this problem and the most popular scheme is the Smith Predictor(SP). In this paper, the dynamic model of a unit apartment in the district heating system, which is the control process effected by the dead-time, is developed, and the on/off room temperature control method with the SP simulate using Matlab-Simulink. The simulation results show that the SP works effectively in outdoor temperature variation.

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단전원 듀얼 인버터의 데드타임으로 인한 영상전류 억제 방법 (Suppression of Zero Sequence Current Caused by Dead-time for Dual Inverter With Single Source)

  • 윤범렬;김태형;이준희;이준석
    • 전력전자학회논문지
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    • 제27권2호
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    • pp.126-133
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    • 2022
  • This study proposes a suppression of zero sequence current (ZSC), which is caused by zero sequence voltage (ZSV) for a dual two-level inverter with single DC bus. Large output voltages enable the dual inverter with single DC bus to improve a system efficiency compared with single inverter. However, the structure of dual inverter with single DC bus inevitably generates ZSC, which reduces the system efficiency and causes a current ripple. ZSV is also produced by dead time, and its magnitude is determined by the DC bus and current direction. This study presents a novel space vector modulation method that allows the instantaneous suppression of ZSC. Based on a condition where a switching period is twice a sampling (control) period, the proposed control method is implemented by injecting the offset voltage at the primary inverter. This offset voltage is injected in half of the switching period to suppress the ZSC. Simulation and experiments are used to compare the proposed and conventional methods to determine the ZSC suppression performance.

주기관 쟈케트냉각수 온도를 위한 피드포워드 제어시스템의 구성과 분석 (Configuration and Analysis of a Feed-forward Control System for Jacket Cooling Water Temperature of Marine Prime Diesel Engine)

  • 최순만
    • Journal of Advanced Marine Engineering and Technology
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    • 제32권8호
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    • pp.1303-1308
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    • 2008
  • Keeping cooling water temperature higher within the allowable range helps marine engines to run in more efficient condition especially when the engine load is low. Temperature control of jacket cooling water in outlet side of main engine has been more widely adopted to ships these days for the purpose to reduce fuel consumption rate. But If the temperature sensor for the control loop is placed at the outlet of engine, it brings more difficulties in attaining stable and desirable properties due to dead times included in pipe length and engine itself comparing to the case where the measuring point is at the inlet side of main engine. In relation with this problem, Feed-forward control could be one of realistic solutions as it reveals good properties and requires less cost for system configuration. This study suggests a forward control system which leads to improved temperature control performances to disturbance signals which could arise from variation of engine load or weather condition. Two dead times in the modelling were described, considering pipe length between the actuator and the engine as well as the thermal process inside the engine. The results of analysis were shown by simulations to confirm responses under different conditions.

Adaptive Control of a Single Rod Hydraulic Cylinder - Load System under Unknown Nonlinear Friction

  • Lee Myeong-Ho;Park Hyung-Bae
    • Journal of Advanced Marine Engineering and Technology
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    • 제29권3호
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    • pp.251-259
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    • 2005
  • A discrete time model reference adaptive control has been applied in order to compensate the nonlinear friction characteristics in a hydraulic proportional position control system. As nonlinear friction, static and coulomb friction forces are considered and modeled as dead zone and external disturbance respectively. The model reference adaptive control system consists of a cascade combination of the dead zone. external disturbance and linear dynamic block. For adaptive control experiment. the DSP(Digital Signal Processor) board has been interfaced the hydraulic proportional position control system. The experimental results show that the MRAC(Model Reference Adaptive Control) for compensation of static and coulomb friction are very effective.

적분기와 큰 시간지연을 가지는 플랜트에 대한 응답특성 개선 (Improved Response of the Plant with an Integrator and Long Dead Time)

  • 양승현;박용식;허명준;이석원
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1999년도 추계학술대회 논문집 학회본부 B
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    • pp.515-517
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    • 1999
  • This paper considers the design of the effective controllers for the plant with an integrator and a long deadtime. The structure of the new DTC(DeadTime Compensator) that has an additive filter is proposed. Our DTC shows the improved performance in set-point response and disturbance rejection. Especially the bad effect of the long deadtime in the disturbance rejection is fairly reduced by using the additive filter. Illustrative examples are provided to show the availability of the proposed controller.

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Nyquist 선도에 의한 개선된 모델 축소 알고리즘 (Improved Model Reduction Algorithm by Nyquist Curve)

  • 조준호;최정내;황형수
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2001년도 합동 추계학술대회 논문집 정보 및 제어부문
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    • pp.215-218
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    • 2001
  • To improve the performance of PID controller of high order systems by model reduction, we proposed a new model reduction method in frequency domain. A new model reduction method we proposed, considered four points (${\angle}G(jw)=0$, $-{\pi}/2$, $-{\pi}$, $-3{\pi}/2$) in stead of two points (${\angle}G(jw)=-{\pi}/2$, and $-{\pi}$) in Nyquist curve. And for high order systems that it have not two point (${\angle}G(jw)=-{\pi}/2$, and $-{\pi}$) in Nyquist curve, we proposed a method to annex very small dead time. This method has a annexed very small dead time on the base model for reduction, and we cancel it after to get the reduced model. It is shown that the performance of proposed method is better than any other methods.

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신속한 생형사(生型砂) 관리(管理)를 위한 기초연구 (A basic study for the rapid green sand control)

  • 김명한;권숙인;강춘식;나달주
    • 한국주조공학회지
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    • 제7권3호
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    • pp.199-206
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    • 1987
  • This paper presents experimental data for the computerization of green sand control. The results can be summarized as follows: 1. To obtain the proper compactability at the mixer, the addtion of moisture is far more efficient than the control of mixing time or addtion of clay. 2. The log R(% clay/% moisture) vs. log compactability curve moves upward as the amount of clay increases and moves downward as the amount of seacoal, dead bentonite or coked seacoal increases. 3. The ratio of dead to initial clay amount or coked to initial seacoal amount is changed according to sand to metal ratio, mainly, and according to pouring temperature, partly, at a shake out time of 12hrs.

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Grid-friendly Control Strategy with Dual Primary-Side Series-Connected Winding Transformers

  • Shang, Jing;Nian, Xiaohong;Chen, Tao;Ma, Zhenyu
    • Journal of Power Electronics
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    • 제16권3호
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    • pp.960-969
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    • 2016
  • High-power three-level voltage-source converters are widely utilized in high-performance AC drive systems. In several ultra-power instances, the harmonics on the grid side should be reduced through multiple rectifications. A combined harmonic elimination method that includes a dual primary-side series-connected winding transformer and selective harmonic elimination pulse-width modulation is proposed to eliminate low-order current harmonics on the primary and secondary sides of transformers. Through an analysis of the harmonic influence caused by dead time and DC magnetic bias, a synthetic compensation control strategy is presented to minimize the grid-side harmonics in the dual primary side series-connected winding transformer application. Both simulation and experimental results demonstrate that the proposed control strategy can significantly reduce the converter input current harmonics and eliminates the DC magnetic bias in the transformer.