Collaborative Self-Standby Adjustment for Photovoltaics with Rotor Inertial Power Source Control Strategy in Weak Power Grids

The energy crisis has accelerated the rapid development of photovoltaic resources. However, the integration of large-scale photovoltaic (PV) systems into the power grid has significantly reduced system inertia, posing significant challenges to grid frequency stability. To enhance the frequency response characteristics of grid-connected PV systems, this paper proposes a rotor inertial power source (RIPS) control strategy for coordinated adjustable self-standby PV systems. First, based on the P-V operating characteristics of a PV system, a control strategy for estimating the maximum power of the PV system and implementing variable step size voltage control is proposed, enabling self-standby control for PV systems to provide primary frequency control capability. Second, by analyzing the transient response of the virtual synchronous generator (VSG) and leveraging its rotor operating characteristics, a RIPS control strategy is introduced to extract rotor inertial power, which increases the system’s inertia. Third, by utilizing the inertial power provided by RIPS in coordination with self-standby PV systems for grid connection, the inertia of the PV grid-connected system is effectively increased, thereby equivalently enhancing the frequency stability of the PV grid connection. The simulation results validate the effectiveness of the proposed control method, providing new insights for the expansion of PV system integration into the grid.