Title page for etd-0729117-152514


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URN etd-0729117-152514
Author Meng-Fen Yang
Author's Email Address No Public.
Statistics This thesis had been viewed 5569 times. Download 7 times.
Department Electrical Engineering
Year 2017
Semester 1
Degree Master
Type of Document
Language zh-TW.Big5 Chinese
Title A Polarity-Switched Flyback Conversion Circuit for Battery Charge Equalization
Date of Defense 2017-08-21
Page Count 50
Keyword
  • Charge equalizer
  • Flyback converter
  • Arrayed switches
  • Constant–current constant-voltage (CC-CV) charging method
  • Lithium iron phosphate battery
  • State-of-charge (SOC)
  • Abstract The thesis proposes a charge equalizer with a polarity-switched flyback converter and the arrayed switches for batteries connected in series. By exchanging the arrayed switches, the charger equalizer can select the target battery, which is with the lowest state-of-charge(SOC). The flyback converter utilizes the full power from charger and at the same time allocate a relatively high current to the target battery. The balance charging scheme employs the constant-current constant-voltage(CC-CV) charging method and estimates the batteries’ SOCs by the loaded voltage method. The balance charging process is accomplished by a regular charging stage, a low-current detection stage, and eventually an individual charging stage. In the first two stages, the balance charging is performed alternately by a detection mode to select a target battery and then a balancing mode to charge it with relatively large current. At the individual charging stage, the series charging current path is cut off and the charge equalizer charges the batteries one by one with CC-CV charging method.
    Experiment tests are carried out on a battery power bank consisting of four serial lithium iron phosphate batteries with the proposed charge equalizer. Experiment results have shown that the charge imbalance can be effectively reduced after the regular charging stage for most practical cases. With a lower detection current, the balance charging period can be extended to further alleviate the SOC difference among the serial batteries. Eventually, all batteries can be charged to their full capacities with individual charging, even if they are initially with extreme imbalance.
    Advisory Committee
  • Chih-Chiang Hua - chair
  • Shiang-Hwua Yu - co-chair
  • Tzung-Lin Lee - co-chair
  • Yao-Ching Hsieh - co-chair
  • Chin-Sien Moo - advisor
  • Files
  • etd-0729117-152514.pdf
  • Indicate in-campus at 0 year and off-campus access at 3 year.
    Date of Submission 2017-09-06

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