Research on power point tracking algorithm considered spinning reserve capacity in gird-connected photovoltaic system based on VSG control strategy

摘要

To improve reliability of micro-grid system without energy storage, a maximum power point tracking (MPPT) algorithm considered spinning reserve capacity was proposed. Using implicit curve fitting method, the algorithm set aside 10% of PV array's maximum output power as spinning reserve of distributed generation (DG), and tracked maximum power point of load in real simultaneously. Moreover, to improve contribution of DG to the required inertia of power system, a photovoltaic virtual synchronous generator (PV-VSG) model was designed. The VSG power controller was presented for its outer-loop, and controller based on inductor current feedback for the inner-loop. The simulation results show that the proposed MPPT algorithm has high accuracy and PV-VSG strategy exhibits inertia and damping characteristics in tracking power command when VSG system power changes or voltage sags. The proposed strategy, which contributes to reduce energy storage costs, can also help achieve a high penetration of PV in grid.