• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.6
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• pp.738-744
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• 2018

This paper proposes a low cost hot swap operation circuit of a parallel operation power supply for servers. Hot swap function for server power system is essential in 24 hour operation system such as internet data center, server, factory and etc. Server power supplies used in internet data centers have two or more parallel operations with the hot swap operation. However, the cost of the power supply is high because the controller IC for hot swap operation is very expensive. Therefore, this paper proposes a parallel-operated power supply with a low-cost hot swap controller for servers. The proposed system can operate hot swap function by using discrete devices and reduce the cost by more than 50%. A 1.2kW prototype system is implemented to verify the proposed low cost hot swap controller.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.482-483
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• 2018

본 논문에서는 Hot-Swap 가능한 모듈라 ESS용 DC-DC 컨버터에서 ESS 모듈의 Hot-Swap 과정에서 발생하는 과도상태에 대해 컴퓨터 시뮬레이션을 통해 분석을 하고, 과도상태에서 과전류를 저감할 수 있는 방법에 대해 제시하고자 한다.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.308-309
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• 2020

본 논문은 추가적인 회로 없이 DVR 전원공급장치의 Hot-Swap 기능을 구현하는 방법을 제안한다. 기존에 사용하던 ORing Diode와 MOSFET의 추가 없이 LLC 컨버터 2차측 정류다이오드만의 바이어스 특성을 이용해 Hot-Swap 기능을 구현한다. 168W급 DVR 전원공급장치를 대상으로 제안한 회로의 타당성을 모의실험을 통해 입증한다.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.433-434
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• 2019

본 논문에서는 직렬형 Hot-Swap ESS(Energy Storage System)에서 하나의 DC-DC 컨버터 모듈이 순간적으로 추가 또는 제거되는 고장 상황에서의 과도 응답에 대해 이론적 분석을 진행하였고, 컴퓨터 모의실험을 통해 분석 결과의 유효성을 검증하였다.

• Proceedings of the KIPE Conference
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• 2018.11a
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• pp.177-178
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• 2018

본 논문에서는 직렬형 Hot-Swap ESS(Energy Storage System)를 구성하는 전력 변환 시스템에서 전류 센서의 옵셋 오차가 제어 성능에 미치는 영향에 대해 살펴보았다. 양방향 DC-DC 컨버터와 DC-AC 인버터에서 전류 센서 옵셋 오차의 영향에 대해 분석하고, 컴퓨터 모의 시험을 진행하여 그 특성을 파악하였다.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.237-239
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• 2005

In this paper PLC Power Circuit with Hot-Swap Function is proposed for stable power supplies. The power modules of the proposed devices are implemented by CRM flyback converter using new synchronous rectifier circuit for high efficiency. By a variable switching frequency controller, this converter is operated with a reduced turn-on switching loss. Also, the load current in these power modules are shared by auto master / slave method using Outer loop. The proposed devices are analyzed in detail and optimized for high performance. Experimental results for a 100W power module at the variable switching frequency of 30$^{\sim}$70kHz were obtained to show the performance of the proposed device.

• Journal of the Korea Convergence Society
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• v.9 no.3
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• pp.31-37
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• 2018

Energy Storage System(ESS) is a system that maximizes energy efficiency by selectively storing and using the generated power when needed. Therefore, energy must be able to be charged or supplied at any time, and non-operating time should be minimized even in the case of failure or maintenance. However, current large-capacity energy storage systems must be shut down during maintenance due to structural problems. In this paper, we propose a PCS for 1MW ESS by configuring modular for large capacity ESS in parallel and verified of the hot swap technology that can replace, change, and repair the components that make up the system while keeping the system operating.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.502-503
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• 2011

최근 환경 문제 및 화석 에너지의 고갈과 맞물려 신재생 에너지를 사용하는 DC 출력형 분산전원 시스템이 증가 일로에 있으며, 이에 따라 교류 급전시스템보다 에너지 변환 효율이 높은 직류 급전 시스템에 대한 연구개발이 활발히 이뤄지고 있다. 본 논문에서는 유지 보수의 용이성을 확보한 Hot Swap 구조형식의 DC 급전용 100[kW]급 분산 제어기반 모듈형 ESS[Energy Storage System의 개발에 관한 것이다. 실제 33[kW]급 모듈 3대로 구성된 100[kW]급 시스템을 제작하여 전압제어 실험, 병렬운전실험 및 Hot Swap 안정성 실험 등을 수행하였다.

• Proceedings of the KIPE Conference
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• 2019.11a
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• pp.212-213
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• 2019

High power and energy applications of battery require a large number of batteries to be connected in series, parallel or mixed configurations. The reliability or these batteries is improved by making them tolerant to faults i.e. by bypassing the fault cells and adding new cells to compensate the voltage and current requirement. The addition or removal or cells may cause the current stress on other healthy cells. The estimation and control or this current stress is one or the technique proposed by other researchers. This study intends to identify a suitable scalable configuration which can either avoid or reduce the efforts on the estimation and control of stress current. In addition, this paper will explore the issues associated with hot-swap.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.2
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• pp.61-66
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• 2023

As the use of smartphones expands to various areas and the level of multitasking increases, the support of swap is becoming increasingly important. However, swap support in smartphones is known to cause excessive storage traffic, resulting in memory thrashing. In this paper, we analyze how the thrashing of swaps that occurred in early smartphones has changed with the advancement of smartphone hardware. As a result of this analysis, we show that the swap thrashing problem can be resolved to some extent when the memory size increases. However, we also show that thrashing still occurs when the number of running apps continues to increase. Based on further analysis, we observe that this thrashing is caused by some hot data and suggest a way to solve this through an NVM-based architecture. Specifically, we show that a small size NVM with judicious management can resolve the performance degradation caused by smartphone swap.