• 전력전자학회:학술대회논문집
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• 전력전자학회 2014년도 추계학술대회 논문집
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• pp.11-12
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• 2014

This paper introduces a scaled hardware model for the 10kVA, 1kV, 11-level MMC (Modular Multilevel Converter), which was manufactured in the lab based on computer simulations with PSCAD/EMTDC. Various experiments were conducted to verify the major operation algorithms of MMC. The hardware scaled-model developed in the lab can be utilized for analyzing the operation analysis and performance evaluation of MMC according to the modulation pattern and redundancy operation scheme.

• Journal of Power Electronics
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• 제16권2호
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• pp.522-531
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• 2016

This paper proposes a new NLC (Nearest Level Control) scheme for MMCs (Modular Multilevel Converters), which offers voltage ripple reductions in the DC capacitor of the SM (Sub-Module), the output voltage harmonics, and the switching losses. The feasibility of the proposed NLC was verified through computer simulations. Based on these simulation results, a hardware prototype of a 10kVA, DC-1000V MMC was manufactured in the lab. Experiments were conducted to verify the feasibility of the proposed NLC in an actual hardware environment. The experimental results were consistent with the results obtained from the computer simulations.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 D
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• pp.2240-2242
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• 2002

This paper show serial communication method in order to design how to interface between fault tolerant systems with redundancy. Problem has been in the method that fault tolerant system had switched of serial data with common switching device. This problem degrade reliability in itself and total system which is interfaced with that serial communication system. So Arbitration module of serial communication which is suggested in this paper can improve the reliability using voter algorithm which fault is detected passively.

• International Journal of Reliability and Applications
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• 제3권3호
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• pp.147-154
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• 2002

In this paper, we consider the warm standby redundant system(WSRS) which is consisted of an active unit, a standby unit and a switchover device. In addition, the switchover processing is controlled by a control module. The effect of failure of the control module is taken into account to develop our reliability model for the redundant structure. For the performance evaluation of a redundant system with the function of switchover processing which is assumed to cause the increase of the failure rate of the system, some reliability indices, such as availability, average availability, reliability and steady state availability, are considered.

• 대한기계학회논문집
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• 제19권1호
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• pp.181-192
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• 1995

In this study, we introduce new types of planar 2 degree-of-freedom robot modules resembling the musculoskeletal structure of the human arm with actuation redundancy. First, for the given actuator sizes the performance analysis for the manipulator with redundant actuation and without redundant actuation is performed with respect to maximum load handling capacity, maximum hand velocity, and maximum hand acceleration. Secondly an algorithm which decides optimal actuator sizes for the given operational performances is introduced, and the optimal actuator sizes for a robot module with four redundant actuation are obtained. The algorithms employed in this paper will be useful to analyze the robot performances and to determine the actuator sizes for general robot manipulators.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2009년도 춘계학술대회
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• pp.903-906
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• 2009

본 연구에서는 임베디드 시스템, 특히 블루투스 베이스밴드에서 사용이 가능한 고속 직렬 포트 인터페이스를 설계하였다. 인터페이스는 ARM 프로세서를 응용할 수 있는 AMBA APB에 호환될 수 있도록 설계하였으며, 8비트 형태로 외부 디바이스와 코프로세서 간 데이터와 명령을 전송할 수 있다. 오류 정정을 위하여, CRC를 적용하였고 멀티미디어 카드를 위한 인터페이스도 제공하였다. 설계한 직렬 포트 인터페이스는 자동합성하여 P&R을 수행하였다. 결과물은 Altera FPGA로 구현하였으며 25MHz에서 정상동작하였다.

• International Journal of Reliability and Applications
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• 제2권2호
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• pp.107-115
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• 2001

This paper considers some reliability indices, such as availability, average availability, reliability and steady state availability, of a redundant system with the function of switchover processing. We also derive the confidence limits for steady state availability of such system. The system, which is considered in this paper, consists of an active unit, a standby unit and a switchover device. In addition, the switchover processing is controlled by a control module. The effect of failure of the control module is taken into account to develop our reliability model for the redundant structure. Numerical examples are presented to illustrate our results.

• 반도체디스플레이기술학회지
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• 제21권1호
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• pp.85-90
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• 2022

In this paper, an asynchronous nonvolatile memory module using a self-diagnosis function was designed. For the system to work, a lot of data must be input/output, and memory that can be stored is required. The volatile memory is fast, but data is erased without power, and the nonvolatile memory is slow, but data can be stored semi-permanently without power. The non-volatile static random-access memory is designed to solve these memory problems. However, the non-volatile static random-access memory is weak external noise or electrical shock, data can be some error. To solve these data errors, self-diagnosis algorithms were applied to non-volatile static random-access memory using error correction code, cyclic redundancy check 32 and data check sum to increase the reliability and accuracy of data retention. In addition, the possibility of application to an asynchronous non-volatile storage system requiring reliability was suggested.

• 전기학회논문지
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• 제62권9호
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• pp.1240-1248
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• 2013

This paper describes a switching-level operation analysis of BTB(Back-To-Back) converter for HVDC(high voltage DC) application based on MMC(modular multi-level converter). A switching-level operation analysis for BTB converter is very important to understand the converter operation in detail and check the voltage and current transients in each components. However, the development of switching-level simulation model for the actual size BTB Converter is very difficult because the MMC normally has more than 150 sub-modules for each arm. So, a switching level simulation model for the 11-level MMC-based BTB converter was developed with PSCAD/EMTDC software, which has 12 sub-modules for the positive arm and another 12 sub-modules for the negative arm. The DC-voltage balance algorithm, the circulating-current reduction algorithm, the harmonic reduction algorithm, and the redundancy operation algorithm were included in this simulation model. The developed simulation model can be utilized to analyze the MMC-based BTB converter for HVDC application in switching level and to develop the protection scheme for the MMC-based BTB converter for HVDC application.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 전력전자학술대회
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• pp.304-305
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• 2011

정보화 사회로 진입함에 따라 전자화 된 정보의 저장 및 관리는 매우 중요한 사안으로 부각되고 있으며 모든 통신기기 및 전산시스템은 365일 가동이 보장되어야 하므로 여러 대의 전원을 병렬 운전하여 신뢰성을 높이고 용량을 증대시키는 방안이 연구되고 있다. 특히, 신뢰성이 요구되는 분야에서는 리던던시(Redundancy) 개념이 중요하게 되어 병렬 운전의 도입이 확산 되고 있다. 현재 새로운 전력 구조는 절연된 컨버터의 평균 전력량을 다운시켜 다수의 전력변환기를 병렬운전 시키는 방향으로 변하고 있으며, 이는 전력변환기의 신뢰성을 증가시키고 예비기기에 대한 부담을 감소시키는 큰 장점을 갖고 있다. 최근에는 이더넷 라이터를 이용하여 부하분담(Load Sharing) 및 핫스왑(Hot-swap)기능을 DC/DC 컨버터에 내장하고 있는 추세이다. 본 연구에서는 7[kW]급 지능형 DC 모듈전원 제어기술 개발에 초점을 두고 최적의 부하분담을 갖는 고성능 전류 제어 알고리즘을 소개하고자 한다.