Title page for etd-0723109-233027


[Back to Results | New Search]

URN etd-0723109-233027
Author Kong-Soon NG
Author's Email Address No Public.
Statistics This thesis had been viewed 5579 times. Download 13 times.
Department Electrical Engineering
Year 2008
Semester 2
Degree Ph.D.
Type of Document
Language English
Title Configuration and Operation of Battery Power Modules
Date of Defense 2009-06-26
Page Count 116
Keyword
  • coulomb counting
  • state-of-health (SOH)
  • state-of-charge (SOC)
  • intermittent discharging
  • battery power module (BPM)
  • Battery
  • Abstract 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.
    Advisory Committee
  • Ching-Tsai Pan - chair
  • Tsai-Fu Wu - co-chair
  • Hong-Chan Chang - co-chair
  • Jia-You Lee - co-chair
  • Tsorng-Juu Liang - co-chair
  • Chih-Chaing Hua - co-chair
  • Jiann-Fuh Chen - co-chair
  • Tsair-Rong Chen - co-chair
  • Chin-Sien Moo - advisor
  • Files
  • etd-0723109-233027.pdf
  • indicate in-campus access in a year and off_campus not accessible
    Date of Submission 2009-07-23

    [Back to Results | New Search]


    Browse | Search All Available ETDs

    If you have more questions or technical problems, please contact eThesys