Research on Harmonic Resonance Mechanism and Inhibition Strategy of LC Type Energy Storage Virtual Synchronous Generator

Virtual Synchronous Generators (VSG) is an effective way to solve the problem of high-permeability new energy grid-connected. However, due to the influence of the external power grid, the filtering circuit oscillation of the LC-type energy storage virtual synchronous generator may be excited, causing a harmonic resonance of the energy storage virtual synchronous generator when connected to the grid, and generating a harmonic resonance risk. First of all, according to the existing LC-type energy storage VSG grid-connected system control strategy, this paper constructs a closed-loop mathematical model to deeply analyze the grid-connected system of energy storage VSG under different grid parameters, and it is found that the harmonic resonance is mainly related to the network side link. Then, in order to suppress the harmonic resonance, this paper introduces the virtual impedance algorithm based on the control strategy of the existing energy storage VSG grid-connected system, and proposes a new type of damping control strategy for energy storage VSG. Finally, a Matlab/Simulink simulation model is established to verify the harmonic resonance phenomenon in the energy storage VSG and the effectiveness of the proposed damping strategy.