A Voltage Control Strategy for PEDF (Photovoltaics, Energy Storage, Direct Current and Flexibility) System

In the context of large-scale integration of new energy into the power grid, PEDF (photovoltaics, energy storage, direct current and flexibility) system has attracted much attention because of its efficient new energy consumption capability. However, the system suffers from the problems of insufficient inertia and poor voltage stability. For this reason, this paper proposes a voltage control strategy with adaptive change of virtual capacitance. By virtualizing an equivalent capacitance on the DC side of the energy storage converter, the capacitance is adaptively adjusted according to the degree of DC bus voltage fluctuation, so as to enhance the inertia of the system, smooth out voltage dips, and maintain the stability of the DC bus voltage. At the same time, this paper improves droop control strategy of the grid-connected converter to achieve bias-free regulation of the bus voltage. Simulation experimental results show that this strategy can effectively regulate the system voltage and significantly improve the dynamic characteristics of the DC bus voltage.