Evaluation of VAR control and voltage regulation functionalities in a single-phase utility-connected inverter for distributed energy applications

With the increased penetration of distributed energy (DE) systems on the electrical distribution network and with the evolving concept of smart grid control and communications, these energy systems can be equipped with their own power electronics, not only for power conversion but also to supply VAR and regulate voltage. Though IEEE 1547 presently does not allow active voltage control by DE sources, the simulation and experimental results presented in this paper confirm that with simple control modification, a single-phase DE inverter can be designed to supply reactive power and regulate voltage at the point of common coupling (PCC), thus such an inverter can be beneficial to the utilities for reducing investment in voltage regulation devices. The implementation of fast prototyping techniques together with modular power electronic devices were utilized to achieve easier, low-cost implementation and prototyping of the DE interface for the experimental evaluation of the control algorithms.