A modularized battery charge equalizer in the application of electric vehicle

For traction of electric vehicles, the motor utilizes battery strings (cells) connected in series. These battery strings suffer from the problem of charge unbalancing due to charging and discharging, chemical degradation and ambient temperature. Contemporary research has reported many charge balancing circuit systems for equalizing the charge among the battery strings of cells. However, charge balancing remains a challenging task as the large number of cells used these days in conventional charge equalizer systems. In this paper, a modularized charge equalizer based on series resonant converter has been designed where the switching loss, conduction loss, balancing time are explored. In the proposed modularized system, the circuit size and cost is minimized and efficiency is increased. In addition, zero current switching have been achieved during turn off intervals of switches.