Accurate Estimating the State of Charge for Rapid Charge System for Lead-Acid Battery

• Main Authors: Sheng-Qin Huang, 黃聖欽
• Other Authors: Kuo-Kai Shyu
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/61285453802769809572

碩士 === 國立中央大學 === 電機工程研究所 === 92 === This thesis presents a PIC-based rapid charger of a Lead-Acid battery. The charger applies Reflex method for battery charge. However, different from existing methods with fixed charging interval, this thesis proposes a more flexible design with variable charging time according to the internal resistance of the battery. Therefore, this thesis firstly proposes an estimating method of the internal resistance of Lead-Acid battery. To prevent the temperature rising of the battery from charging, the charger will discharge when the internal resistance reaches a threshold value. Moreover, for estimating the state of charge accurately, a fuzzy estimator is proposed by observing the voltage variation of the charging state of the battery. With the estimator, not only the capacity of battery can be obtained immediately, but also the suitable charging current can be controlled to protect the battery, which can lengthen the battery life. For the purpose of observing the experimental process, a window display, which shows current, voltage, remaining Coulomb, and temperature, is designed by using Visual Basic.