Research on Frequency Modulation Capability of Motor Generator Pair Driven via Photovoltaic Power Generation

Large-scale new energy units connected to the grid can reduce the inertia of the power system, and the motor generator pair (MGP) can provide a real, time-free inertia response for the grid. Based on the structure of MGP grid-connected system, the electric-mechanical model of MGP is established, and the inertia response principle of MGP and virtual inertia control is compared. By comparing the similarities and differences of frequency response between traditional unit and new energy synchronizer, an active power control strategy based on photovoltaic load shedding operation and droop control is proposed. The inertia response ability of MGP and the effectiveness of the improved control strategy are verified in the simulation system with 3 machines and 9 nodes. Furthermore, the improvement effect of the proposed strategy on the frequency modulation ability of photovoltaic is verified by comparing with the virtual inertia and droop control strategy. The simulation results generated from PSCAD/EMTDC show that the improved control strategy can enhance the frequency response ability of photovoltaic grid connected by MGP.