Research on digital control bi-directional full bridge DC/DC converter

This paper proposes a digital control based bidirectional DC/DC converter on the secondary side of which an active clamp branch is added. In the buck mode adopting the ZVZCS phase-shifted full-bridge scheme, the active clamp branch realizes the ZVS and ZCS respectively on the leading and lagging legs and effectively restrains the spurious resonance on the secondary side. In the isolated boost mode, the active clamp branch can limit the voltage spike of the power MOSFETs, which reduces the EMI noise in the system. No redundant element can be found in this converter, minimizing power loss and ensuring high efficiency. The operation principle of the converter is analyzed and a 2 KW experimental prototype connecting to a 400V DC bus and a 48V storage battery is designed to test the feasibility and correctness of the proposal.