Research on Smooth Switching Method of PMSG Control Strategies between Grid Following Control and Grid Forming Control

The grid forming permanent magnet synchronous generator (PMSG) based on virtual synchronous generator control (VSG) faces complex working requirements, and the grid side inverter often needs to change the control strategy according to the operating conditions. These switching processes are often accompanied by voltage and frequency fluctuations, posing a challenge to the stability of the system. This paper proposes a novel smooth switching strategy of PMSG grid forming converter for the transition between different grid connected modes. This strategy proposes a switching method that includes a self closing loop to regulate the dq axis reference currents, in order to maintain the stability of the reference currents at the moment of switching. Finally, based on the RTLAB and RTU-BOX, a hardware in the loop experimental testing platform was built to verify that the proposed control strategy can achieve smooth switching of grid forming converters in different operating and control modes.