Analysis and design of PPFHB bidirectional DC-DC converter with coupled inductors

In this paper, a novel push-pull-forward half-bridge (PPFHB) bi-directional DC-DC converter with coupled inductors is proposed. All switches can operate under zero-voltage-switching (ZVS). The operation principle with phase-shift modulation scheme, characteristics of coupled inductors, the steady state relationship and small-signal model are analyzed. The voltage controller based on the small-signal model in z-domain is designed. A 500 W prototype controlled by TMS320F2808 DSP is implemented and tested. Experimental results show the validity of the analysis and design.