Transconductance Model of the Dual Active Bridge Converter Under Single and Dual Phase Shift Control

This work proposes a model for the Dual Active Bridge (DAB) converter that recognizes the dominant dynamics and simplifies analysis. The DAB converter is a complex topology with eight semiconductor switches and a high frequency transformer. The DAB is widely applied in literature based on a myriad range of benefits including low losses, galvanic isolation, and excellent power density. The proposed model is based on the recognition of the first order system dynamics that dictate the control-to-output-voltage response. This model utilizes a transconductance term and simplifies analysis significantly compared to previous approaches reported in the literature. This simplification however maintains high accuracy at the terminals of the DAB converter compared to other modeling approaches. This modeling approach benefits the practicing engineer by allowing more efficient simulation of the converter and an intuitive understanding of the dominant features of the DAB. The DAB transconductance model is presented along with time and frequency domain simulations. The model is then validated against a physical DAB converter with resistive load. In recognition of the limitations of the single-phase shift modulation scheme, the transconductance modeling approach is extended to the dual phase shift modulation control.