Voltage Control Architectures for the Universal Operation of DPGS

The future concept of universal operation embraces those distributed power generation systems (DPGS) capable of getting disconnected from the main grid to start operating within an island. Once the cause of disconnection is solved, the DPGS is able to resynchronize and reconnect with the grid. In these conditions, the universal operation can be successfully implemented through a voltage control. Voltage control is manly adopted in uninterruptible power supply (UPS) and island applications. However, a study that solely focused on the universal operation is missing. The goal of this work is to help in the selection of the most suitable control structure as function of: 1) power dynamics, power quality, and robust stability in grid-connected; 2) voltage regulation and performance under local load steps in island mode; and 3) behavior during the reconnection with the grid. For that purpose, five architectures have been reviewed within a general mathematical framework and with experimental results.