• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.41-45
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• 1997

To design a control system, it is a elementary point that the stability of the system should be guaranteed. Also, the phase of the system plays an important role for its frequence performance. In this paper, we present two stability criterion of repetitive control system with phase-lead and lag compensator. First, the stability criterion for the servo control system with phase-lead and lag compensator is shown by using small-gain theorem. Second, for the repetitive control system with the compensator, the stability criterion, also, is determined by using small-gain theorem. Two stability criterions show the same results that the stability depends on a coefficient of the phase-lead and lag compensator under some condition in servo control system and repetitive control system.

• Journal of Power Electronics
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• v.15 no.2
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• pp.443-454
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• 2015

This study proposes a novel one-cycle control scheme with a plug-in repetitive controller for load compensator. The novelty of this scheme lies in the combination of high dynamics and the simplicity of a one-cycle controller and good steady-state harmonic suppression ability of the repetitive controller. In addition, the proposed scheme can reduce the effect of the harmonics in phase voltage for the existence of the repetitive controller. Finally, experimental results on a three-phase, four-wire, three-level load compensator are reported to validate the effectiveness of the proposed control scheme.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.7
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• pp.1342-1348
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• 2009

DSTATCOM(distribution static compensator) is one of the custom power devices, and protects a distribution line from unbalanced and harmonic current caused by non-linear and unbalanced loads. Researches about DSTATCOM are mainly divided two parts, one is the calculation of compensated current and the other part is the current control. This paper proposes a proportional-resonant-repetitive current controller. Improved performance of instantaneous power compensation has been shown by simulations and experiments.

• Journal of Power Electronics
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• v.13 no.6
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• pp.1070-1079
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• 2013

This paper develops an enhanced harmonic voltage compensator which is implemented with the aid of two repetitive controllers (RCs) in order to improve the output voltage performance of stand-alone distributed generation (DG) systems. The proposed harmonic voltage compensator is able to maintain the DG output voltage sinusoidal regardless of the use of nonlinear and/or unbalanced loads in the load side. In addition, it can offer good steady-state performance under various types of loads and a very fast dynamic response under load variations to overcome the slow dynamic response issue of the traditional RC. The feasibility of the proposed control strategy is verified through simulations and experiments.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.6
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• pp.37-42
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• 2008

In H.264/AVC decoder, intra predictor, motion compensator, and deblocking filter need to read reference images in external frame memory in decoding process. They read external frame memory very frequently, which lowers system operation speed and increases power consumption. This paper proposes a intra predictor integrated with motion compensator without external frame memory. It achieves power reduction and memory bandwidth minimization by exploiting data reuse of common and repetitive pixels. The proposed infra predictor achieves more than $45%\;{\sim}\;75%$ cycle time reduction compared with conventional intra predictors.

• Journal of Broadcast Engineering
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• v.8 no.2
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• pp.146-152
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• 2003

ATSC DTV receivers use repetitive data segment syncs or Gardner algorithm as a tuning recovery circuit. Many multipath signals can induce timing-offset in the symbol timing recovery circuit using Gardner algorithm and this timing-offset shifts sampling instant to the wrong points, causing the performance of the equalizer to become nr. When many echoes exist, the optimal sampling instant will be the Point at which the main-path has a peak value. In this paper, by using channel correlation techniques, we find the optimal sampling instant, thereby compensating the timing offset and improving DTV reception performance. We analyzed the Performance enhancement of DTV receivers using the timing offset compensator.