Due to the advanced features of multidirectional power transfer and fast smoothing of the power fluctuation in renewable energy systems

the multiple-active-bridge based power-electronic-transformer (MAB-PET) with integrated energy storage units is becoming popular. However

the accurate electromagnetic transient simulation of the MAB-PETs is extremely time-consuming due to the large number of circuit nodes and small time-step. This paper proposes a simplified EMT modeling approach for the MAB-PETs by employing the generalized state-space averaging method. First

the switching function method and Dommel algorithm are used to build the equivalent model of each power module. Further

the PET equivalent model is presented in a multi-port PM polymerization mode. The system is simplified by applying Fourier Decomposition to its state functions by ignoring high-order harmonics. Finally

a four-port equivalent voltage source circuit is obtained. The proposed simplified equivalent model is compared with the detailed model in PSCAD/EMTDC. Simulation results show the proposed approach has excellent accuracy and is 2–3 orders of magnitude faster than the DM.