Time-Domain Modeling and Power Decoupling of the Cross-Coupled Active Power Flow in a Multi Active Bridge (MAB) Converter

The principal component within the multi active bridge (MAB) topology is the high-frequency magnetic link (HFML) interconnecting multiple ports, thereby facilitating multidirectional power flow. However, a byproduct of this unifying AC magnetic link is the cross-coupled power flow induced by the inter-port phase shifts, subsequently preventing independent port-wise operation. Therefore, this work presents a time-domain analytical framework for the accurate estimation of the cross-coupled active power flow by applying a superposition-based approach to the MAB port-equivalent models. These port-equivalent models are derived from the full-order$n \times n$inductance matrix ($\mathbf {L}$-matrix) extracted from an asymmetric integrated-leakage HFML via a single-port impedance measurement scheme. Furthermore, a control-integrated power decoupling (IPD) feedforward compensator is developed to suppress undesirable propagative voltage fluctuations during transient power flows, thereby ensuring port-wise decoupling of the converter. Steady-state experiments conducted on a 3.2 kW SiC-based four-port MAB prototype are used to validate the accuracy of the proposed time-domain model with respect to the terminal active powers. Whereas transient experiments with output-voltage step-changes are used to verify the improved decoupling performance of the proposed full-order$\mathbf {L}$-matrix IPD scheme, in comparison with an uncompensated PI (Proportional-Integral) controller, and the existing$Y$-$\Delta$(star-delta) decoupling method.