Control Design for 3-Phase Bidirectional Battery Chargers with Multiple Battery Charging Capabilities for Electric Vehicle Fleet Applications

This paper describes a control structure for a bidirectional battery charger model design which consists of three-phase PWM ac/DC converters linked to a DC/DC converter with a CLLC-type resonant tank circuit. It presents a control structure that accommodates: constant current, constant voltage (CCCV) charging algorithm of an Energy Storage System (ESS), a multiple battery charger setup, and the automation of the combined control system based upon certain conditions being satisfied. The proposed control scheme was simulated and validated for a system integrating two battery charger modules using the PLECS software tool while charging a Li-ion battery model. The interactions between the two modules during the charging process were investigated with and without the introduction of a DC bus.