Triangular-Shaped and Simultaneous Adjustment of Inertia and Damping in VSG-based Distributed Energy Resources for Improved Frequency Response

The concept of virtual synchronous generators (VSGs) has been introduced as a viable control methodology for interfacing power electronic-based distributed energy resources (DERs) with the grid. This paper investigates a family of VSG control mechanisms with variable parameters; and proposes a new approach that simultaneously adjusts both the virtual inertia and damping in order to improve the overall frequency response of the DERs. The proposed method employs simplified triangular-shaped trajectories for changing the inertia and damping coefficients. Specifically, the proposed controller simultaneously increases both the virtual inertia and damping parameters based on the measured load disturbance in the power system, and decreases them linearly with an adjustable slope, which offers a simple implementation. The effectiveness of the proposed method is verified using computer simulations of a small-scale power system including a DER and a load. It is shown that the proposed control method improves the dynamic frequency response compared to the existing state-of-the-art VSG control techniques.