Synthetic inertia for BESS integrated on the DC-link of grid-tied PV inverters

The significant mechanical inertia of the rotor in a synchronous generator is crucial for facilitating the cooperative grid forming capability of multiple such generators on the transmission and distribution network. This paper demonstrates that the DC link capacitance in a PV inverter is the analogous form of inertia for such a system, albeit having much smaller magnitude. Furthermore it proposes using storage integrated on the DC link to synthesize extra inertia by programming the storage power electronics controller to achieve an emulated capacitance. Inertia added to distributed energy resources (DERs) in this manner is the first step towards mitigating the power quality issues arising from increased renewable penetration on the network. Demonstration of the acquired inertia dynamics and verification of the required controller design is shown through a detailed simulation model.