Control and Sizing of Two-Stage Smart Transformer in Meshed Hybrid Distribution Grid

Increased penetration of renewable energy in electric distribution grid requires installation of more power electronics devices and complex controller. In such scenario, smart transformer (ST) is a promising solution as it can control both power and voltage simultaneously with available dc links to integrate batteries and electric vehicles. This paper propose an ST-based meshed hybrid distribution grid where low voltage (LV) ST power converter is eliminated and realized by the distributed generation (DG) converters. The DG converters are connected through the extended LVDC line formed by the ST LVDC link. This configuration significantly reduces the rating of power converters in LV grid. Moreover, the LV side DG converters are operated with droop control which allows power management in LV grid without any communications among the DG converters.