High power full bridge DC/DC converter using digital-to-phase-shift PWM circuit

With the advent of the high-speed microprocessor and DSP, the possibility of executing a control strategy in the digital domain has become a reality. Therefore, by the use of a DSP controller instead of using the analog controller UC3879, a phase-shifted zero-voltage-switching (ZVS) full-bridge (FB) DC/DC power converter can be controlled easily. In this paper, a digital-to-phase shift PWM circuit for a fully digital controlled ZVS FB DC/DC converter is presented and a promising solution for the DC bias control of a high frequency transformer is also proposed. The operating principles and experimental results on a 40 kW, 20 kHz experimental prototype are presented.