Virtual Synchronous Generator with Variable Inertia Emulation Via Power Tracking Algorithm

Abstract

This paper proposes the technique, variable inertia emulation of the virtual synchronous generator (VSG) fed from a photo voltaic (PV) source via power tracking algorithm. The virtual synchronous generator is tied to a three-phase distribution line at the point of common coupling (PCC). The operating point on the power - voltage characteristics of the PV source is suitability controlled to emulate the inertia in the input. The variable inertia is achieved through variation of inertia constant in the closed loop power control. This method of moving on the power - voltage characteristics requires a power tracking algorithm for the PV Source. The VSG is modeled using synchronous reference frame theory with a voltage oriented control scheme(VOC). We have chosen an improved version of phase locked loop(PLL) for the accurate estimation of the phase and extraction of the fundamental component from the voltage at PCC. The droop control characteristics determine the real power and reactive power to be supplied by the VSG. The simulation results support the analysis presented in this paper.