Generalized averaging modeling and control strategy for three-phase dual-active-bridge DC-DC converters with three control variables

In this paper, different order generalized state-space averaging (GSSA) models are derived for a three-phase dual-active-bridge (3p-DAB) dc-dc converter with PWM control scheme. The small-signal model based on GSSA model is deduced and a comparison between different models and a circuit simulation is made. Subsequently, a closed-loop control strategy with an optimal limitation unit is proposed for 3p-DAB converters. The control strategy can operate the converter in a closed loop with any optimized modulation scheme to enhance the efficiency and other performances. The controller parameters can be easily designed based on the 2nd-order GSSA model. Finally, the experimental results are presented to verify the effectiveness of the small-signal model and the proposed control strategy.