Single-Stage Matrix-Type Solid-State Transformer Based on Push–Pull DAB

This article presents a single-stage matrix-type solid-state transformer, which integrates a shared filter capacitor between the line frequency (LF) rectifier and the high frequency half bridge on the primary side, a modified push–pull dual active bridge to eliminate the leakage inductor effect on the secondary side, and a full-bridge LF inverter on the load side. Due to its electrolytic capacitorless nature, the proposed structure ensures identical instantaneous powers, thereby eliminating ripple power with double grid frequency, and unit power factor is inherently performed without a current control loop. Moreover, the operating characteristics of the converter under resistive and inductive–resistive loads are analyzed respectively, examining the conditions for zero voltage switching with time-varying dc-link voltage and the factors affecting total harmonic distortion. In addition, optimization strategies to reduce operating losses are considered in the parametric design. Finally, a 1 kW prototype is constructed and tested to validate the correctness and feasibility of the proposed method.