Analysis and design of a simple digital control algorithm for a phase-shift full-bridge DC-DC power converter

In this paper it is presented an analysis and design of a digital control algorithm implemented on a digital signal processor, a dsPIC30F2020. A dc-dc converter prototype is built based on a full-bridge (FB) dc-dc converter topology. Extensive simulations in time domain and digital domain are explored and experimental results are also shown to validate the performance of this particular dc-dc converter. Basically, the dc-dc power converter will operate in a phase-shift (PS) mode along with a current-doubler high-frequency feature. This current-doubler scheme will allow an increase of output current capability with a low dc-output voltage under special load conditions. A prototype of a current-doubler has been built and tested on a phase-shift full-bridge (PSFBC) dc-dc converter with a 6V of dc-output voltage, and 2.5A for output current. A direct digital control design methodology is discussed, as well as simulation and experimental results of a digital controller are presented. Extensive discussion on experimental results and design issues are presented.