Open AccessA switched‐capacitor battery equalization method for improving balancing speed
Author(s) -
Sun Wenbin,
Li Yanling,
Liu Lizhou,
Mai Ruikun
Publication year - 2021
Publication title -
iet electric power applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.815
H-Index - 97
eISSN - 1751-8679
pISSN - 1751-8660
DOI - 10.1049/elp2.12045
Subject(s) - battery (electricity) , voltage , switched capacitor , pulse width modulation , capacitor , equalization (audio) , computer science , energy (signal processing) , electrical engineering , topology (electrical circuits) , control theory (sociology) , electronic engineering , engineering , channel (broadcasting) , power (physics) , mathematics , control (management) , physics , statistics , quantum mechanics , artificial intelligence
The switched‐capacitor equalizer (SCE) has a broad application prospect because of its small size, easy control, and implementation. However, the conventional SCE by shifting energy between two adjacent cells usually has a lower balancing speed the number of imbalanced battery cells increases. Therefore, an automatic SCE is proposed to improve the balancing speed for a long battery string. The main advantage of the proposed method is taking the highest‐voltage battery cell as the source for balancing. By controlling the MOSFETs alternately with one pair of complementary pulse width modulation signals, the energy can be directly delivered from the highest‐voltage battery cell to other lower‐voltage ones, to avoid the frequent energy inflow or outflow from the same battery cell. A prototype for four lithium battery cells is implemented, and the comparisons between the proposed SCE and other SCEs in simulation and experiment are presented. Results show that the proposed SCE topology exhibits an obvious improvement in balancing speed at different initial voltage mismatch distributions.