Bi-directional pulse charger for li-ion battery based on the current amplitude modulation technique

• Main Authors: Bo-ting Shen, 沈柏廷
• Other Authors: Chang-hua Lin
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/11462496963122912959

碩士 === 大同大學 === 電機工程學系(所) === 97 === This thesis proposes a improved ReflexTM battery charger for lithium battery, consisting of two stages. The first stage, which is a flyback topology, mainly provides the power factor correction, electrical isolation and step-down conversion. The second stage is a bi-directional topology, supplying the positive and negative pulse charging. Next, in order to avoid overcharging or charge insufficiency, this thesis proposes a pulse charging strategy according to the instantaneous electrical capacity of the battery based on the current amplitude modulation technique. Furthermore, the electrical capacity detection is integrated by the open-circuit voltage method, which is more precise for initial capacity detection and the coulomb method, which is suitable for long term monitoring, to determine the charging pulse amplitude. Therefore, the proposed improved ReflexTM method may simultaneously prolong the battery life and achieve the rapid charging. Moreover, the mathematical models of each operation mode are also derived. All the experimental results agree with the computer simulations to verify the theoretical predictions.