Internal and external characterization of multiparallel voltage source energy storage converters

Voltage source converter-based energy storage system (ESS-VSC) participates in power system frequency regulation actively. In this paper categorizes the stability characterization of ESS-VSC into external and internal characteristics, and establishes the impedance model of ESS-VSC to analyze the stability impacts causing by the increasing number of parallel ESS-VSCs. In addition, the transfer function of parallel ESS-VSCs is developed to analyze its frequency response stability caused by virtual inertia and damping parameter with the Bode diagram. Finally, a simulation model is developed using Matlab/Simulink platform to validate the accuracy of the simulation analysis.