VSG Fuzzy Control Strategy of Energy Storage in Grid-connected Mode

Abstract

In order to solve the large fluctuation of system frequency and power during load changes and single-phase ground faults, a virtual synchronous machine (VSG) fuzzy control strategy of energy storage in grid-connected mode is proposed. Firstly, the influence of virtual inertia and damping on system dynamic performance is analyzed based on the frequency and power curves. Secondly, considering the allowable maximum frequency change rate and the energy storage discharge characteristics, the lower and upper ranges of inertia are determined. Then the fuzzy rules are designed for the proposed VSG fuzzy control strategy, which can improve the microgrid stability via flexibly changing the system inertia and damping. Finally, the simulation on MATLAB/Simulink and the comparison with the existing methods have verified that the proposed strategy can reduce the power and frequency fluctuations as well as the demand for energy storage capacity.