A high-power high-frequency self-balanced battery charger for lithium-ion batteries energy storage systems

Abstract

Lithium-Ion traditional energy storage systems need bidirectional converters for the charging process and some separate systems for eliminating cells voltage imbalances. These systems have complex and voluminous structures due to numerous switches, multiple transformers, and several sensors. Here, a phase-shifted full-bridge (PSFB) converter with a current doubler rectifier and a voltage multiplier circuit for lithium-ion batteries is proposed. By combining both charging and balancing systems, a super-integrated system is achieved which simplifies the structure. Since the balancing circuit neither has power MOSFETs nor sensors and bulky magnetic components, a simple topology is obtained. By using the PSFB converter and the voltage multiplier circuit in charging and balancing sections, respectively, the proposed super-integrated converter benefits from simultaneous charging and balancing operations, high efficiency, simple structure, high power density, voltage imbalances eliminating, and proper isolation. The operation principles of the converter are analyzed, minutely. The charging and the balancing experimental results performed for 8 battery modules include 48 lithium-ion cells demonstrate simultaneous charging and balancing operations of the proposed self-balanced topology, as well.