Design of digital compensators for multi-output DC-DC converters with reduced cross-regulation

Abstract

ABSTRACT In the recent times, a single multi-port DC-DC converter (MPC) is highly preferred over the multiple single output DC-DC converters. Single Input Dual Output (SIDO) Buck converter with Coupled Inductors (CI) are widely employed for the reduction of multiple outputs. In this paper, the prognostic procedures to monitor MPC operating with load dynamics are discussed. The occurrence of cross-regulation during the load dynamics is suppressed by an improved digital compensator, which was specifically designed to address the cross-regulation problem. The developed digital compensation circuit is employed in the CI-SIDO Buck converter with an input of 48 V and delivering outputs of 12 V/75Watts and 24 V/125 Watts. The occurrence of cross-regulation is controlled by decoupled dual loop digital PID controller with dynamical digital compensation. A meticulous Frequency Response Analysis (FRA) with bode plot is conducted exhaustively for the derived system transfer functions. The proposed design is verified in simulation and experiments, exhibiting an enhanced results with significant suppression in cross-regulation and stability.