Modeling and Stability Assessment of Single-Phase Droop Controlled Solid State Transformer

This paper addresses the modeling aspects and small-signal stability considerations for a single-phase droop controlled Solid State Transformer (SST). A state-space based modeling approach is utilized to assess the stability of the SST. It is demonstrated that physical parameter (e.g. grid impedance) variations, the choice of control parameters (e.g. droop control parameters) and the steady state operating point play a crucial role in determining the stability of the SST system that needs to handle wide load variations. Simulation results from a 1kVA droop-controlled SST system are presented to validate the analytical models.