Implementation and design of high-power fast charger for lithium-ion battery pack

The high-power fast charger (HPFC) incorporating a power stage with a controlling loop is presented in this paper. A power stage is composed of an inter-leaved boost power factor correction and a DC-DC full-bridge phase-shifted (FBPS) converter, and that the HPFC can supply a constant-voltage (CV) or a constant-current (CC) power to charge a secondary lithium-ion battery pack. In addition, the ripple current can be reduced due to the DC-DC FBPS converter combines with the current-doubler rectifier at HPFC's output side. Also, the controlling loop is equipped with a voltage compensator and a current compensator, and this design is for the sake of HPFC, which can either operate in CV or CC output mode. Moreover, the shut-down situation will be prevented by proposed bi-phase charging controller, when the charging current is adjusted from the fist CC level to the second CC level. Analysis and design considerations of the proposed circuits are presented in details. Experimental results agree well with the theoretical predictions and confirm the validity of the proposed approach.