Adaptive hybrid control of grid-connected VSC with grid-following and grid-forming duality and its transient stability analysis

The application scope of grid-following control and grid-forming control for voltage source converters has certain limitations，so an adaptive hybrid control of grid-connected voltage source converter with grid-following and grid-forming duality is proposed. This control combines the grid-following control and grid-forming control flexibly，and introduces adaptive coefficients into the synchronous control loop and voltage control loop. The proportion of grid-following control and grid-forming control in the control loop can be adjusted by changing the value of the adaptive coefficient，so that the converter can adapt to different operating conditions. The research results show that by changing the adaptive coefficient of the synchronous control loop and increasing the proportion of the phase-locked loop in the synchronization loop under alternating current faults，the active power reference value of the converter can be reduced，the inertia and damping can be increased，and the transient stability of the system can be improved. Changing the adaptive coefficient of the voltage outer loop，increasing the proportion of grid-following control in the voltage outer loop can increase the voltage at the gird connection point，thereby enhancing the stability of the system. After adopting the proposed control strategy，the converter can maintain stable operation under active power step conditions with different short-circuit ratios and different degrees of grid voltage sag conditions. A voltage-source converter grid-connected simulation model is built in PSCAD／EMTDC，and the results verify the feasibility and effectiveness of the adaptive hybrid control strategy. © 2025 Electric Power Automation Equipment Press. All rights reserved.