Operating Region of a Genset-Based Virtual Synchronous Generator

This paper introduces the concept of the operating region of a virtual synchronous generator (VSG). The main objective of the operating region is to help take a decision on choosing proper VSG parameters. A VSG based on a diesel generator (Genset) model was used as the study case. The theoretical analysis examined the impact of relevant genset-based VSG parameters, such as droop factor, mdr, inertia, J, and damping, D, on the output electrical frequency. The main result of this analysis showed that it is possible to define inertia-damping surfaces which are parameterized upon different values of the droop factor. The operating region of the VSG is then defined as the locus of the triples (mdr, J, D) where the frequency transient response satisfies certain specifications in terms of peak frequency, peak time and rate of change. Experimental results showed that the VSG achieved a satisfactory performance for different values of speed droop during a transient and also in steady-state, validating the model of the genset. In comparison with simulation results, the measured peak frequencies deviated with a mean absolute error of 0.2 % and the steady-state frequencies with a mean absolute error of 0.12 %, validating the concept of the operating region.