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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Investigation on Intermittent Discharging Profiles for Lead-Acid Batteries

Lin, Yu-Chao 08 July 2007 (has links)
This thesis studies the operating characteristics of lead acid batteries with the intermittent discharging current. Rest time is added periodically on purpose during the battery discharging to observe its impact on the releasable capacity. From the experimental results that take the frequency and the duty-ratio as two variables, batteries with the intermittent discharging at high frequencies or low duty ratios can release more capacity. The results also indicate that the depth of discharge (DOD) affects the intermittent discharging. More capacity is released while approaching the end of the discharging, whereas no clear difference is found in the beginning. Last but not least, the average current is proved experimentally to play a significant role in current discharging. With the same average current, the maximum capacity obtained from the intermittent current discharging is close to that from the constant current discharging.
2

Configuration and Operation of Battery Power Modules

NG, Kong-Soon 23 July 2009 (has links)
A novel battery power system configured by the battery power modules (BPMs) is proposed. Each BPM consists of a single battery pack or a battery bank equipped with an associated DC/DC converter. The output ports of BPMs can be connected in series for the high voltage applications, or in parallel to cope with a higher power or energy. For a large scale battery power system, a number of BPMs can be arrayed with combination of series and parallel connections to meet the load requirements. These all configurations allow the BPMs be operated individually. Consequently, the discharging currents of the batteries can be independently controlled, but coordinated to provide a full amount of the load current. The performances of BPMs connected in both parallel and series at outputs are analyzed theoretically and discussed from the experimental results. Batteries operating independently do not suffer from charge imbalance, and thus can avoid being over-charged or over-discharged, so that the life cycle can be prolonged. Furthermore, sophisticated discharging profiles such as intermittent currents can be realized to equalize the charges and thus to efficiently utilize the available stored energy in batteries. During the operation period, some of the batteries may take rest or be isolated from the system for the open-circuit measurement, facilitating the estimation of the state-of-charge (SOC) and the evaluation of the state-of-health (SOH). With the benefit of independent operation, the BPMs can be discharged with a scheduled current profile, such as intermittent discharging. The investigation results show that the average current plays the most important role in current discharging. By detecting the battery voltage at the break time, an SOC estimation method based on the dynamically changed open-circuit voltage exhibits an acceptable accuracy in a shorter time with considerations of the previous charging/discharging currents and the depth-of- discharge (DOD). In addition, the coulomb counting method can be enhanced by evaluating the SOH at the exhausted and fully charged states, which can be intended on the independently operated BPMs. Through the experiments that emulate practical operations, the SOC estimation methods are verified on lead-acid batteries and lithium-ion batteries to demonstrate the effectiveness and accuracy.
3

INVESTIGATION OF THE ELECTROPHYSIOLOGICAL PROPERTIES OF THE MAJOR CELL TYPES IN THE RAT OLFACTORY TUBERCLE

Chiang, Elizabeth C. January 2008 (has links)
No description available.

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