• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2007년도 하계학술대회 논문집
• /
• pp.175-177
• /
• 2007

An analysis on a passive current sharing characteristics of a multi-phase synchronous buck converter is presented. The passive current sharing method is simple but its characteristics depend on the converter equivalent resistance and PWM uniformity. In this paper, the load sharing and power consumption of the passive current sharing system for the converter equivalent resistance and duty ratio inequalities are investigated through the simulation and experiment.

• Nuclear Engineering and Technology
• /
• 제51권1호
• /
• pp.60-72
• /
• 2019

The air-cooled passive decay heat removal system (APDHR) was proposed to provide the ultimate heat sink for non-LOCA accidents. The APDHR is a modified one of Passive Auxiliary Feed-water system (PAFS) installed in APR+. The PAFS has a heat exchanger in the Passive Condensate Cooling Tank (PCCT) and can remove decay heat for 8 h. After that, the heat transfer rate through the PAFS drastically decreases because the heat transfer condition changes from water to air. The APDHR with a vertical heat exchanger in PCCT will be able to remove the decay heat by air if it has sufficient natural convection in PCCT. We conducted the thermal-hydraulic simulation by the MARS code to investigate the behavior of the APR + selected as a reference plant for the simulation. The simulation contains two phases based on water depletion: the early phase and the late phase. In the early phase, the volume of water in PCCT was determined to avoid the water depletion in three days after shutdown. In the late phase, when the number of the HXs is greater than 4089 per PCCT, the MARS simulation confirmed the long-term cooling by air is possible under extended Station Blackout (SBO).

• 전자공학회논문지
• /
• 제51권2호
• /
• pp.220-226
• /
• 2014

본 논문에서는 Passive RFID system으로 구성된 Smart Floor 환경에서 다 개체 로봇의 효율적인 영역 탐색 방법을 제안한다. 연구에서 사용된 Passive RFID system 은 RF 안테나의 인식 범위 내에 있는 RF 태그에 사용자가 원하는 정보를 저장하고 읽을 수 있다. 본 연구에서는 명시적인 위치정보를 저장한 RF 태그를 바닥에 매설한 Smart Floor 라는 환경을 구축하였고, 로봇에 설치되어 있는 안테나를 통하여 태그로부터 받아들인 위치정보를 논문에서 제안하는 방법으로 가공하여 모바일 로봇의 위치를 추정함과 동시에 Smart Floor 내의 다른 로봇에게 자신의 이동 흔적을 남김으로써 기존 탐색 기법에 비해 전체 영역 탐색 시간을 단축하여 효율을 높였다. 본 논문에서는 Smart Floor 환경을 활용하여 모바일 로봇의 효율적인 이동 알고리즘을 제안한다.

• Journal of Electrical Engineering and Technology
• /
• 제1권4호
• /
• pp.461-465
• /
• 2006

This paper presents a useful and simple method to design the passive skimming system for homogeneous permanent magnets based on numerical optimization. To simulate the effects of manufacturing and assembling tolerances, the actual geometrical parameter of the magnet with a derivation is suggested. Then, the optimal design model oi a passive shim system is set up to correct the derivative of field homogeneity. The numbers, sizes and locations of the passive shims are optimized by the steepest descent algorithm combined with design sensitivity analysis. Two implementations show that the proposed method can achieve the required homogeneity of the field with the minimum quantity of ferromagnetics.

• 전기학회논문지P
• /
• 제59권1호
• /
• pp.64-70
• /
• 2010

This paper presents how to decide on tuning factor(${\delta}$) and quality factor(Q) values in design of single-tuned passive harmonic filters. Tuning factor(${\delta}$) and quality factor(Q) values have to consider before decision on circuit parameters of passive filters. A Study on these two value has not been scarcely performed and only experienced values has been used in passive harmonic filter design by far. As a experienced value, in cases of 5th and 7th filter, tuning factor(${\delta}$) is about 0.94 and 0.96 respectively and quality factor(Q) is, in all cases of, 50. If Single-tuned passive harmonic filter will be off-tuned, performance of filter will be decreased steeply and occur to parallel resonance between system reactance and filter capacitance. Therefore During the operation, In order not to off-tuning, Filter must be tuned at former order than actual tuning order. This is the same that total impedance of filter must have a reactive impedance. In this paper, Tuning factor(${\delta}$) is decided via example of real system and using the bode-plot and then performance of filters confirmed by filter current absorbtion rate. And Quality factor(Q) decided using the bode plot in example system and then performance of filters confirmed by filter current absorbtion rate also, which makes a calculated filter parameters to satisfy IEEE-519 distortion limits. Finally, Performance of the designed passive harmonic filter using the tuning factor(${\delta}$) and quality factor(Q) values, decided in this paper is verified by experiment and shows that 5th, 7th, 9th, 11th and 13th current harmonic distortions are decreased within IEEE-519 distortion limits, respectively.

• KIEAE Journal
• /
• 제11권4호
• /
• pp.55-61
• /
• 2011

Due to global warming issues caused by climate changes which are internationally being highlighted, recently, there are lots of efforts under way to reduce energy consumption in various fields. Currently, 25 percent of energy consumption in Korea are being generated from buildings and especially, nearly 54 percent of them are being consumed by households. This study, therefore, aims to consider energy consumption status in the existing rural houses and analyze structure system performance, window system performance and air-permeability of domestic passive-type buildings using PHPP which is an analysis program of building energy to improve energy consumption problems in rural areas. Then, energy reduction plans in rural houses were proposed, by comparing and analyzing energy reduction of the existing rural houses, based on these data.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
• /
• pp.304-306
• /
• 2005

This paper presents the RTDS training course on using passive filters for control of harmonic currents. The course can show harmonic currents in porer system, which is occurred by function generators, with Fourier analysis function of RTDS and the effect of passive filters implemented in RTDS to eliminate harmonics. In addition to, With Jeju-Haenam HVDC system, we have simulated the effect of passive filters on harmonic currents occurred by massive power conversion system of HVDC.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2005년도 ICCAS
• /
• pp.813-816
• /
• 2005

This paper presents a method for harmonic elimination and reactive power compensation using an intervening firing method and passive power filter with is suitable to compensate rapidly changing loads and reactive power. The proliferation of three-phase thyristor phase-controlled converter of DC motor drives into a power system has the potential to increase the harmonic levels in the power system. The design procedure of an intervening firing method and passive power filter capable of reducing the voltage and current harmonics produced by converter supplied from a source having internal large inductive impedance is offered. The analysis uses the or CAD PSpice to model three-phase thyristor phase-controlled converter of DC motor drives as well as the system.

• 한국유체기계학회 논문집
• /
• 제17권6호
• /
• pp.84-88
• /
• 2014

A long term passive cooling system is considered as the most important safety feature for the nuclear design after the Fukushima Daiichi nuclear power plant accident in 2011. The conventional active pump driven safety systems are not available during a station Black Out (SBO) accident. The current design requirement on cooling time of the Passive Auxiliarly Feedwater System (PAFS) is about 8 hours only. To meet the 72 hours cooling time, the pool capacity of cooling water tank should be increased as much as 3~4 times larger than that of current water cooling tank. In order to extend the cooling time for 72 hours, a new passive air-water combined cooling system is proposed. This paper provides the feasibility of the combined passive air-water cooling system. The current pool capacity of water cooling system is preserved, and the cooling capability is extended by an additional air cooler.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년도 학술대회 논문집 전문대학교육위원
• /
• pp.224-228
• /
• 2006

The aim of this study is to design a passive filter for the elimination of harmonics. For this design, the harmonics wave generating from the six pulse rectifier was measured and its characteristics were analyzed. We also calculated the quantity of harmonic current by changing the system operational conditions. According to this field data and calculated results, we determined the elements of the passive filter. The simulation and experimental results indicate the efficiency of designed passive filter.