Voltage Stability Assessment of a Dual Active Bridge Based Solid State Transformer in a Smart Distribution System with Buck-Boost Converter

Solid-state Transformer (SST) is a collection of high power semiconductor components and a high-frequency transformer, which enhances power quality by the means of preventing voltage imbalance and providing voltage regulation, harmonic filtering, reactive power compensation, disturbance & fault isolation. Due to its stronger electric field, quick switching capabilities, and extremely low switching loss, Silicon Carbide (SiC)-based Dual Active Bridge (DAB) is employed in the design of the SST. This topology has a buck-boost converter to regulate the output voltage for a variable input voltage. Buck-boost converter keeps the output voltage constant for any kind of voltage variation on the input side. This paper analyzes the functionality of the buck-boost converter to keep the voltage constant up to a 50% change in the input value to the desired output voltage. The future smart distribution system must have this controlled mechanism. Results from simulations using MATLAB are provided to illustrate the approach.