Mobile QR Code QR CODE : The Korean Institute of Power Electronics
Title Enhanced Switching Pattern to Improve Energy Transfer Efficiency of Active Cell Balancing Circuits Using Multi-winding Transformer
Authors Sang-Jung Lee ; Myoungho Kim ; Ju-Won Baek ; Jee-Hoon Jung
DOI 10.6113/TKPE/2019.24.4.279
Page pp.279-285
ISSN 1229-2214
Keywords Active cell balancing; Cell balancing techniques; Multi-winding transformer; BMS(Battery Management System); Energy transfer efficiency
Abstract This study proposes an enhanced switching pattern that can improve energy transfer efficiency in an active cell-balancing circuit using a multiwinding transformer. This balancing circuit performs cell balancing by transferring energy stored in a specific cell with high energy to another cell containing low energy through a multiwinding transformer. The circuit operates in flyback and buck-boost modes in accordance with the energy transfer path. In the conventional flyback mode, the leakage inductance of the transformer and the stray inductance component of winding can transfer energy to an undesired path during the balancing operation. This case results in cell imbalance during the cell-balancing process, which reduces the energy transfer efficiency. An enhanced switching pattern that can effectively perform cell balancing by minimizing the amount of energy transferred to the nontarget cells due to the leakage inductance components in the flyback mode is proposed. Energy transfer efficiency and balancing speed can be significantly improved using the proposed switching pattern compared with that using the conventional switching pattern. The performance improvements are verified by experiments using a 1 W prototype cell-balancing circuit.