Research on the Virtual Oscillation Control Strategy Based on the Cascaded H-Bridge Converter

In order to cope with the stability problem of grid-connected converters in the power system with a high penetration rate of renewable energy, the grid-forming (GFM) control has gradually become a research hotspot. Cascaded H-bridge (CHB) converters have many flexible units for expansion, which can avoid the resonant circulating current problem caused by the parallel of multiple GFM converters. Compared with the other GFM control methods, power calculations and low-pass filters are not required in the virtual oscillation control (VOC), which has a faster dynamic response. Therefore, this paper focuses on the VOC control based on the CHB converter, comparing with the droop control without the inner loop, the small-signal stability and dynamic response of the VOC control are better. Finally, simulation is carried out in MATLAB/Simulink for verification.