Control of single-stage AC-AC solid state transformer for power exchange between grids

A power management control method is proposed for the three-phase-to-single-phase matrix converter (MC)-based solid state transformer (SST) linking two grids. The MC-SST presents low weight and high controllability with respect to a conventional line-frequency transformer. Moreover, the single-stage ac-ac power conversion and compact volume are achieved compared to a three-stage SST, owing to the absence of electrolytic capacitors. The current studies focused on the modulation techniques of this type of SST. Whereas, this paper proposes a control method to manage the active power exchange and power flow when such SST applied to distribution grids, which could be different voltage levels and frequency. Simulation studies are carried out to investigate the proposed method.