Abstract: Cascaded power electronic transformer（PET） for hybrid AC/DC distribution networks can realize multiple functions such as flexible interconnection, voltage conversion, electrical isolation and power control. Due to the high degree of electrical coupling between the cascaded H-bridge and the dual active bridge stage in the cascaded PET with different control objectives, a hierarchical decoupling control scheme is proposed to simplify the control architecture and achieve independent flexible control at all levels. Since the topology of cascaded PET adopts input-series output-parallel（ISOP） of multiple power units, a control strategy of series voltage equalization and parallel current equalization based on hierarchical decoupling control is proposed to reduce the influence of parameter differences. A cascaded PET with rated AC voltage of 10 kV, rated DC voltage of 750 V and rated capacity of 500 kVA is developed, and the experimental results verify the feasibility and effectiveness of the engineering application of the control scheme.