Control of Wound Field Synchronous Machine Gensets for Operation in a CERTS Microgrid

The objective of this work is to determine how an internal combustion (IC) engine driven wound field synchronous genset can be used most effectively as a DG in a microgrid environment. The genset operates synchronously which implies that the speed of the engine needs to be regulated within a narrow range to ensure that the terminal voltages meet the desired power quality standards. The focus of this work is to study the modeling and control issues related to IC engine driven wound field synchronous generators for their operation in a distribution system that contains multiple DG's. A special challenge posed by the genset is the fact that its dynamic response is considerably slower than that of several other types of DG sources that have much faster power electronic interfaces to the microgrid. Conventional IC engine gensets utilize a voltage regulator that controls the terminal voltage to a fixed value. In a distribution system like the microgrid that has multiple sources, the regulation of the voltage to a constant value results in large circulating VAR's in the system. These circulating VAR's decrease efficiency of the system and increase the rating of components.