Design and performance evaluation of digital control for LLC series resonant dc-to-dc converters

This paper presents the design and performance evaluation of the digital control adapted to an LLC series resonant dc-to-dc converter operating with wide input and load variations. The main theme of this paper is to highlight the advantage of using the push-pull mode of digital pulse width modulation (DPWM) operation over the complementary mode operation for the implementation of digital control to the resonant converters using a low cost digital signal controller (DSC). Conventionally, the complementary mode of DPWM operation is used for resonant converter. However, the push-pull mode of DPWM operation is chosen for the resonant converter circuit to improve closed-loop performance. Design procedures and performance evaluation are illustrated for both DPWM operational modes using an experimental 150 W LLC converter.