• Journal of Institute of Control, Robotics and Systems
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• v.9 no.2
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• pp.117-123
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• 2003

Rotational machines such as optical disk drives, hard disk drives, and so on are subject to periodic disturbances caused by their mechanical characteristics. In the meanwhile, it is well known that repetitive control rejects periodic disturbance effectively. This paper presents a practical application of repetitive control to the track-following servo of an optical disk drive. The repetitive control system is composed of two repetitive controllers which compensate for periodic disturbances generated by track geometry and eccentric rotation of disk and a feedback controller stabilizing the feedback loop. A robust stability for all plant uncertainties is proved using linear matrix inequalities (LMIs). In the controller design, a weighting function is introduced for the feedback controller to ensure a minimum loop gain and a sufficient phase margin. The repetitive controllers and the feedback controller are designed by solving an optimization problem which can consider the robust stability condition and the system performance. The developed repetitive control system is implemented in the digital control system with a 16-bit fixed-point digital signal processor (DSP). Through simulation and experiment. The feasibility of the proposed repetitive control system is verified.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.9
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• pp.33-41
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• 2015

To improve the power quality of distributed generation (DG) systems even in the presence of distorted grid condition, dual current control scheme of a grid-connected inverter is proposed. The proposed current control scheme is achieved by decomposing the inverter state equations into the fundamental and harmonic components. The derived models are employed to design dual current controllers. The conventional PI decoupling current controller is used in the fundamental model to control the main power flow in DG systems. At the same time, the predictive control is applied in the harmonic model to suppress undesired harmonic currents to zero quickly. To decompose the voltage inputs and state variables into the fundamental and harmonic components, the fourth order band pass filter (BPF) is designed in the discrete-time domain for a digital implementation. For experimental verification, 2kVA prototype of a grid-connected inverter has been constructed using digital signal processor (DSP) TMS320F28335. The effectiveness of the proposed strategy is demonstrated through comparative simulation and experimental results.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1094_1095
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• 2009

최근 분산전원 시스템들이 가정이나 공공기관 등에 많이 설치되면서 계통에 많은 문제점을 일으키고 있다. 이러한 문제점을 연구하기 위해서는 계통 등의 실제 시스템을 설치하여 실험을 하여야 하는데 학교 연구실 입장에서는 실제 시스템을 설치하여 실험하는데 한계가 있다. 그러나 실시간 전력 계통 모의장치 (Real Time Digital Simulator)를 이용하여 실시간으로 시스템을 시뮬레이션 할 경우 다양한 알고리즘의 적용이 가능하고, 고장, 전력계통 과도현상 등 계통에 일어날 수 있는 여러 가지 상황을 손쉽게 고려해 보는 것이 가능하다. 본 논문에서는 RTDS 내 계통 연계형 태양광 발전시스템을 실제 시스템과 유사하게 모델링하고, 실제 DSP (Digital Signal Processor) 를 이용하여 시스템을 실시간으로 운전하는 HILS (Hardware In the Loop System) 시스템을 구성하였다.

• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.6-8
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• 2006

변전소 자동화 시스템에서 IED(Intelligent Electronic Device)들 간의 효과적인 통신을 위해 표준프로토콜인 IEC-61850이 제시되면서 이를 구현하고 응용하기 위한 관심이 높아지고 있다. 본 논문은 IEC-61850 표준규격을 분석하여 제시된, 거리 계전 IED 모델을 이용해 송전선 보호 IED를 구현하였다. 통신기능 구현은 리눅스 커널 2.6 기반의 통신보드를 사용하였고 계전 알고리즘의 수행은 TMS320C32 기반의 DSP(Digital Signal Processor) 보드를 사용하였다. 보드간 통신은 CAN(Cont roller Area Network) 통신으로 이루어 졌으며 사례연구를 위해 RTDS(Real Time Digital Power System Simulator)를 이용하여 입력신호를 생성하였다. 구성된 시스템의 검증을 위해 거리계전기에서 후비보호 시 발생할 수 있는 문제점을 시뮬레이션 하였다.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.5
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• pp.381-388
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• 2003

In this paper, the IED(Intelligent Electronic Devices) with the consideration of harmonic problems is discussed, With significant development of power electronics technology, the proliferation of a nonlinear load has more deteriorated power quality, As continuous harmonic current makes for a shortening lifetime, overheat and abnormal operation, it should be considered to improve these problems. However, the conventional digital protective relay which eliminates harmonic elements with orthogonal filter has a defect on actually implementation. The prototype IED is constructed with Digital Signal Processor(TMS320C32) and Complex Programmable Logic Device. According to the experiment and simulation results, it is proved that the proposed system has good performance of measuring harmonic factors and protecting electrical equipment.

• Journal of Power Electronics
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• v.16 no.6
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• pp.2109-2118
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• 2016

Based on the space vector pulse width modulation (SVPWM) theory, this paper realizes an easier SVPWM strategy, which is equivalently implemented by CBSPWM with zero-sequence voltage injection. The traditional SVPWM strategy has no effect on controlling the neutral-point voltage balance. In order to solve the neutral-point voltage unbalance problem for neutral-point-clamped (NPC) three-level inverters, this paper proposes a neutral-point voltage balance controller. The proposed controller realizes controlling the neutral-point voltage balance by dynamically calculating the offset superimposed to the three-phase modulation waves of an equivalent SVPWM strategy. Compared with the traditional SVPWM strategy, the proposed neutral-point voltage balance controller has a strong ability to balance the neutral-point voltage, has good steady-state performance, improves the output waveforms quality and is easy for digital implementation. An experiment has been carried out on a NPC three-level inverter prototype based on a digital signal processor-complex programmable logic device (DSP-CPLD). The obtained experimental results verify the effectiveness of the proposed neutral-point voltage balance controller.

• Journal of Biomedical Engineering Research
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• v.25 no.3
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• pp.165-169
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• 2004

In Magnetic Resonance Electrical Impedance Tomography (MREIT), we inject current through electrodes placed on the surface of a subject and measure the induced magnetic flux density distribution using an MRI scanner. This requires a constant current source whose output pulses are synchronized with MR pulse sequences. In this paper, we present a design and performance analysis of a current source used in a 3.0T MREIT system. The developed current source was tested using a saline phantom. We found that its performance is satisfactory for the current MREIT system. We suggest future improvements for better SNR(signal-to-noise ratio).

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.17-22
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• 2009

DaVinci processors are popular media processors for implementing embedded multimedia applications. They support dual core architecture: ARM9 core for video I/O handling as well as system management and peripheral handling, and DSP C64+ core for effective digital signal processing. In this paper, we propose our efforts for optimal implementation of object tracking algorithm in DaVinci-based smart camera which is being designed and implemented by our laboratory. The smart camera in this paper is supposed to support object detection, object tracking, object classification and detection of intrusion into surveillance regions and sending the detection event to remote clients using IP protocol. Object tracking algorithm is computationally expensive since it needs to process several procedures such as foreground mask extraction, foreground mask correction, connected component labeling, blob region calculation, object prediction, and etc. which require large amount of computation times. Thus, if it is not implemented optimally in Davinci-based processors, one cannot expect real-time performance of the smart camera.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.10 s.352
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• pp.27-34
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• 2006

This paper has implemented a very small($1.4{\times}2.8[Cm^2]$) 13.56[MHz] RFID reader ensuring machine ID recognition correctly in a noise space of Tag-to-Reader within 3Cm. For operation of the RFID system, at first, this paper has designed the loop antenna of a reader and the fading model of back-scattering on microwave propagation following to 13.56[MHz] RFID Air Interface ISO/IEC specification. Secondly, this paper has proposed the automatically path selected RF switching circuit and the firmware operation relationship by measuring and analyzing the very small RFID RF issues. Finally, as a very small reader main body, this paper has shown the DSP board and software functions made for extraction of $1{\sim}2$ machine ID information and error prevention simultaneously with carrying of 13.56[MHz] RFID signals that the international standard specification ISO/IEC 18000-3 defined.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.537-540
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• 1992

This paper presents Samsung CNC (Computer Numerical Controller) system with an intel 80486/487 as the main CPU and a 32 bit floating point DSP(Digital Signal Processor) TMS320C30 as the motion control CPU. The Samsung CNC system diverse user-frienly characteristics such as multi-tasking, powerful menu system, internal PLC system, and 2/3 dimensional graphics in wire and solid mode. The main CPU executes central processing program, user interface program, interpreter, BMI, etc while the motion control CPU carries out some interpolations, acceleration/deceleration, and PID control algorithm with feedforward terms. Complex interpolations except linear and circular ones are performed on the main control CPU. The experimental results for the circular interpolation under linear acceleration/deceleration shows that the proposed CNC system can be widely used in controlling machining centers with good machining accuracy.