A series of integrated equalizers based on joint buck-boost (BB) and switched-capacitor (SC) converters are proposed for balancing the voltages of series-connected battery packs. All these equalizers realize the any-cells-to-any-cells (AC2AC) equalization mode without increasing the count of MOSFETs and drivers. Corresponding operational principles are analyzed and the expressions of balancing currents are derived by analytical methods and verified by experimental waveforms. According to the comparative balancing experiments for four and six series-connected Li-ion cells, one proposed CBB-PCSC equalizer, which achieves the dual AC2AC balancing modes through the integration of both coupled buck-boost (CBB) and parallel-connected switched-capacitor (PCSC) converters, leads to the highest balancing speed and efficiency. Moreover, compared with several conventional equalizers, this CBB-PCSC topology also has the compact size and low cost, making it become a well-performing integrated topology for automotive battery voltages equalization.
Bibliographical noteFunding Information:
This work was supported in part by Royal Society Wolfson Research Merit Award (NoTEMP) and in part by Horizon 2020, RISE Project No. 872001, in part by the Faraday Institution funded Nextrode Project EP/T012412/1.
© 1967-2012 IEEE.
- any-cells-to-any-cells mode
- electric vehicles
- Li-ion batteries management
- voltage equalization