Effective selection switching of battery state of charge equalization based on fuzzy logic algorithm

State of Charge (SOC) equalization is an essential function in the battery management system (BMS), especially for a large number of series-connected battery packs. Unbalance SOC distribution in the battery pack may lead to a residual capacity reduction or even dangerous events caused by the weakest cells in a series-connected battery pack. In this work, a new proposed fuzzy-based algorithm is presented as an alternative solution to achieve effective energy transfer for direct pack-to-cell of 15 series-connected Lithium pack to be used on-grid application. The work uses simulation approaches with real-world parameters for system models. The proposed fuzzy-logic-based algorithm (FBA) has been designed and compared to the conventional voltage-based algorithm (VBA) and conventional SOC-based algorithm (SBA). The FBA is capable to improves the effectiveness, speed, and efficiency compared to VBA and SBA. Among those three performances, the switching effectiveness of selective equalization is significantly advanced by the FBA.