Modeling and Stability Analysis of Parallel Grid-Forming Converter Systems Based on Virtual Oscillator Control and VSG Control

The grid-forming converter has voltage source characteristics that can support the grid voltage and frequency, effectively improving the stability of power systems with power electronics. The Andronov-Hopf-Oscillator-based Virtual Oscillator Control (AHO-based VOC) strategy has emerged as a novel approach in recent years. As for a system of parallel gridforming converters includes both this strategy and the Virtual Synchronous Generator (VSG) control strategy, the stability of the system has rarely been studied so far. In this paper, a threephase system with two grid-forming converters in parallel is established. Subsequently, a small-signal model of the system is built, and the influence of controller parameter and transmission line parameters on the small-signal stability of the system is investigated. Simulation results show that the system remains stable when the parameters are changed and has better power quality than the parallel system only using VSG control.