| URN |
etd-0729117-152514 |
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| Author |
Meng-Fen Yang |
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| Author's Email Address |
No Public. |
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| Statistics |
This thesis had been viewed 5569 times. Download 7 times. |
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| Department |
Electrical Engineering |
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| Year |
2017 |
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| Semester |
1 |
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| Degree |
Master |
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| Type of Document |
|
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| Language |
zh-TW.Big5 Chinese |
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| Title |
A Polarity-Switched Flyback Conversion Circuit for Battery Charge Equalization |
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| Date of Defense |
2017-08-21 |
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| Page Count |
50 |
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| Keyword |
Charge equalizer
Flyback converter
Arrayed switches
Constant–current constant-voltage (CC-CV) charging method
Lithium iron phosphate battery
State-of-charge (SOC)
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| 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. |
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| 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
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| Files |
Indicate in-campus at 0 year and off-campus access at 3 year. |
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| Date of Submission |
2017-09-06 |
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