• Title/Summary/Keyword: Passive operation.

Search Result 410, Processing Time 0.027 seconds

Electronic Ballast Design Driven by Low Frequency Square Wave for High Power MHL (고출력 MHL용 구형저주파 구동 방식의 전자식 안정기 설계)

  • Kim, Ki-Nam;Park, Jong-Yun;Choi, Young-Min
    • The Transactions of the Korean Institute of Power Electronics
    • /
    • v.15 no.5
    • /
    • pp.394-400
    • /
    • 2010
  • In this paper, We proposed electronic ballast that applys Buck Converter operation principle to Full-Bridge inverter. The proposed ballast consists of an EMI Filter, a full-bridge rectifier, a passive power factor correction (PFC) circuit and a full-bridge inverter. The passive PFC is used and a Full-Bridge inverter operation by two frequency. High Side and Low Side switch was driven by high frequency and low frequency and realized buck Converter's operation. The lamp is driven by Low Frequency square wave to avoid Acoustic Resonance. Also, bulk of inductor is reduced by high frequency switching. Performance of the proposed ballast was validated through computer simulation using Pspice, experimentation and by applying it to an electronic ballast for a prototype 700W MHL.

Analysis and Implementation of a New Single Switch, High Voltage Gain DC-DC Converter with a Wide CCM Operation Range and Reduced Components Voltage Stress

  • Honarjoo, Babak;Madani, Seyed M.;Niroomand, Mehdi;Adib, Ehsan
    • Journal of Power Electronics
    • /
    • v.18 no.1
    • /
    • pp.11-22
    • /
    • 2018
  • This paper presents a single switch, high step-up, non-isolated dc-dc converter suitable for renewable energy applications. The proposed converter is composed of a coupled inductor, a passive clamp circuit, a switched capacitor and voltage lift circuits. The passive clamp recovers the leakage inductance energy of the coupled inductor and limits the voltage spike on the switch. The configuration of the passive clamp and switched capacitor circuit increases the voltage gain. A wide continuous conduction mode (CCM) operation range, a low turn ratio for the coupled inductor, low voltage stress on the switch, switch turn on under almost zero current switching (ZCS), low voltage stress on the diodes, leakage inductance energy recovery, high efficiency and a high voltage gain without a large duty cycle are the benefits of this converter. The steady state operation of the converter in the continuous conduction mode (CCM) and discontinuous conduction mode (DCM) is discussed and analyzed. A 200W prototype converter with a 28V input and a 380V output voltage is implemented and tested to verify the theoretical analysis.

Problems and improvement methods of passive treatment systems for acid mine drainage in Korea

  • Ji, Sang-Woo;Ko, Ju-In;Kim, Sun-Joon
    • 한국지구물리탐사학회:학술대회논문집
    • /
    • 2003.11a
    • /
    • pp.504-510
    • /
    • 2003
  • This study has been carried out to evaluate the passive treatment systems for acid mine drainage in Korea and to suggest, if possible, the method for the improvement. 35 passive treatment systems in 27 mines have been constructed since 1996. SAPS, being the main process, was combined with more than one of processes such as anaerobic wetland, aerobic wetland, and oxidation pond for the construction of passive treatment system. Problems observed during the operation include the poor sulfate removal ratio, overflow, leakage, unusabless of the whole system, and inefficiency. The reasons of the poor sulfate removal ratio are believed that the low temperature during the winter prohibits the SRB activity and HRT for bacterial sulfate reduction is insufficient. An alternative method In Adit Sulfate Reducing System which enables to keep the temperature constant at about $15^{\circ}C$ was suggested. IASRS is the methods of placing the SAPS inside the adit, which enables the temperature around the system constant can be maintained. The experiments using the laboratory scaled model systems made up of four sections showed high efficiencies in pH control and metal removal ratios, but showed still low sulfate removal ratio of about $23\%$ also with high COD at the beginning of the operation.

  • PDF

Advanced Reactor Passive System Reliability Demonstration Analysis for an External Event

  • Bucknor, Matthew;Grabaskas, David;Brunett, Acacia J.;Grelle, Austin
    • Nuclear Engineering and Technology
    • /
    • v.49 no.2
    • /
    • pp.360-372
    • /
    • 2017
  • Many advanced reactor designs rely on passive systems to fulfill safety functions during accident sequences. These systems depend heavily on boundary conditions to induce a motive force, meaning the system can fail to operate as intended because of deviations in boundary conditions, rather than as the result of physical failures. Furthermore, passive systems may operate in intermediate or degraded modes. These factors make passive system operation difficult to characterize within a traditional probabilistic framework that only recognizes discrete operating modes and does not allow for the explicit consideration of time-dependent boundary conditions. Argonne National Laboratory has been examining various methodologies for assessing passive system reliability within a probabilistic risk assessment for a station blackout event at an advanced small modular reactor. This paper provides an overview of a passive system reliability demonstration analysis for an external event. Considering an earthquake with the possibility of site flooding, the analysis focuses on the behavior of the passive Reactor Cavity Cooling System following potential physical damage and system flooding. The assessment approach seeks to combine mechanistic and simulation-based methods to leverage the benefits of the simulation-based approach without the need to substantially deviate from conventional probabilistic risk assessment techniques. Although this study is presented as only an example analysis, the results appear to demonstrate a high level of reliability of the Reactor Cavity Cooling System (and the reactor system in general) for the postulated transient event.

The Experimental Research for the Collecting Characteristics of the Passive and Active type Domestic Solar Hot Water Systems (자연형 및 설비형 태양열 온수기의 집열특성에 대한 실험적 연구)

  • Lee, Dong-Won;Lee, Kyoung-Ho
    • Journal of the Korean Solar Energy Society
    • /
    • v.33 no.6
    • /
    • pp.12-18
    • /
    • 2013
  • Domestic solar hot water system can be divided into a passive type and an active type. In a passive type the storage tank is horizontally mounted immediately above the solar collectors. No pumping is required as the hot water naturally rises into the storage tank from the collectors through thermo-siphon flow. While, in an active type the storage tank is ground- or floor-mounted and is below the level of the collectors; a circulating pump moves water or heat transfer fluid between the storage tank and the collectors. We installed two types solar hot water systems consisting of the same storage tank and collectors at the same place, and were measured and compared typical operating characteristics under the same external conditions. In particular, the daily system performance was presented through the stirring test after the sunset. The results show that the amount of solar radiation obtained for an active type were less than a passive type on a cloudy day, because the operation of the circulation pump stops frequently took place on that day. However, on a sunny day, depending on the stable operation of the circulation pump, the amount of solar radiation obtained for an active type were increased than a passive type.

Soft-Switching Boost Chopper Type DC-DC Power Converter with a Single Auxiliary Passive Resonant Snubber

  • Nakamura Mantaro;Myoui Takeshi;Abudullh Al Mamun;Nakaoka Mutsuo
    • Proceedings of the KIPE Conference
    • /
    • 2001.10a
    • /
    • pp.256-260
    • /
    • 2001
  • This paper presents boost and buck and buck-boost DC-DC converter circuit topologies of high-frequency soft switching transition PWM chopper type DC-DC high power converters with a single auxiliary passive resonant snubber. In the proposed boost power converter circuits operating under a principle of ZCS turn-on and ZVS turn-off commutation schemes, the capacitor and inductor in the auxiliary passive resonant circuit works as the loss less resonant snubber. In addition to this, the switching voltage and current peak stresses as well as EMI and RFI noises can be basically reduced by this single passive resonant snubber. Moreover, it is proved that converter circuit topologies with a passive resonant snubber are capable of solving some problems of the conventional hard switching PWM processing based on high-ferquency pulse modulation operation principle. The simulation results of this converter are discussed as compared with the experimental ones. The effectiveness of this power converter with a single passive resonant snubber is verified by the 5kW experimental breadboad set up.

  • PDF

A Study on the Control System of Passive Filter to Reduce Harmonics (고조파 저감을 위한 수동필터의 제어시스템에 관한 연구)

  • 전정채;유재근;이상익
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
    • /
    • v.18 no.4
    • /
    • pp.124-130
    • /
    • 2004
  • In this paper, we developed DSP(Digital Signal Processor)-based control system to automatically open and close passive filter, which is used to reduce harmonics, according to operating condition of loads. Passive filter control system automatically open and close each branch of filter according to working conditions of loads by sending signals to open and close installation of passive filter after measuring and monitoring voltage, current, harmonics, reactive power, power factor and so on. We verified it's performance by connecting control system with passive filter in the power line using the 100HP D.C motor drive, opening and closing passive filter according to operation condition of motor, and measuring harmonics and reactive power, etc.

Design of Passive Treatment Systems for Mine Drainage Waters

  • Jeen, Sung-Wook
    • Journal of Soil and Groundwater Environment
    • /
    • v.22 no.2
    • /
    • pp.1-9
    • /
    • 2017
  • Passive treatment systems are commonly used for remediation of mine drainage waters because they do not require continuous chemical inputs and operation. In this study, the selection and design criteria for such systems were evaluated, particularly the two most commonly used ones, i.e., permeable reactive barriers (PRBs) and vertical flow biological reactors (VFBRs). PRBs and VFBRs are operated on the same principles in terms of biochemical reaction mechanisms, whereas differences relate to configuration, engineering, and water management. In this study, each of these systems were described with respect to key design variables, such as metal removal mechanisms and removal rates, effectiveness and longevity, general design and construction, flow capacity, and cost. The information provided from this study could be used as a design guideline when a passive treatment option is considered for potential remediation of a mine site.

A Low Noise Broadband Light Source and its Application on WDM-PON (저잡음 특성의 광대역 비간섭성 광원과 파장 분할 다중방식 수동형 광가입자망에의 응용)

  • Choi Ki-Man;Moon Jung-Hyung;Lee Chang-Hee
    • Journal of the Institute of Electronics Engineers of Korea TC
    • /
    • v.43 no.5 s.347
    • /
    • pp.68-76
    • /
    • 2006
  • We propose a low noise broadband light source (BLS) and investigate a cost-effective wavelength division multiplexing-passive optical network (WDM-PON) for the convergence of broadcasting and data service. The proposed BLS is used for an injection light of wavelength-locked Fabry-Perot laser diodes (F-P LD) and helps the color-free operation of dense WDM-PON (DWDM-PON). In addition, we apply this BLS to a optical source for overlay of digital broadcasting channel on the WDM-PON.

DEVELOPMENT OF AN OPERATION STRATEGY FOR A HYBRID SAFETY INJECTION TANK WITH AN ACTIVE SYSTEM

  • JEON, IN SEOP;KANG, HYUN GOOK
    • Nuclear Engineering and Technology
    • /
    • v.47 no.4
    • /
    • pp.443-453
    • /
    • 2015
  • A hybrid safety injection tank (H-SIT) can enhance the capability of an advanced power reactor plus (APR+) during a station black out (SBO) that is accompanied by a severe accident. It may a useful alternative to an electric motor. The operations strategy of the H-SIT has to be investigated to achieve maximum utilization of its function. In this study, the master logic diagram (i.e., an analysis for identifying the differences between an H-SIT and a safety injection pump) and an accident case classification were used to determine the parameters of the H-SIT operation. The conditions that require the use of an H-SIT were determined using a decision-making process. The proper timing for using an H-SIT was also analyzed by using the Multi-dimensional Analysis of Reactor Safety (MARS) 1.3 code (Korea Atomic Energy Research Institute, Daejeon, South Korea). The operation strategy analysis indicates that a H-SIT can mitigate five types of failure: (1) failure of the safety injection pump, (2) failure of the passive auxiliary feedwater system, (3) failure of the depressurization system, (4) failure of the shutdown cooling pump (SCP), and (5) failure of the recirculation system. The results of the MARS code demonstrate that the time allowed for recovery can be extended when using an H-SIT, compared with the same situation in which an H-SIT is not used. Based on the results, the use of an H-SIT is recommended, especially after the pilot-operated safety relief valve (POSRV) is opened.