Emulated inertia control for a modular multi-level converter-based PV system to improve grid inertia

High penetration of renewable energy sources (RES) through power electronic converters results in a significant displacement of synchronous generators and decreasing in inertia. To solve the issue, this paper proposes an emulated inertia control (EIC) for a modular multi-level converter (MMC) based solar PV system. The proposed EIC exploit the energy stored in the submodule capacitance of MMC. The proposed system does not need any external energy storage systems to enhance the inertia of the grid. The energy stored in the submodule capacitance of the MMC is used in the inertial response. The proposed EIC technique at the MMC maintains stability during and after the contingency event. This paper correlates the inertia constant of MMC and synchronous generator. The simulation results show that the proposed EIC at MMC enhances the inertia of a weak grid.