There is a coupling phenomenon between active power control and reactive power control in a grid-connected system controlled by virtual synchronous generator (VSG) technology

which increases the oscillation amplitude and settling time of the system’s dynamic response. In severe cases

shutdowns may be triggered due to voltage and current limit violations. To resolve the problem

the power coupling matrix model in the dq reference frame and the power balance equations for the VSG grid-connected system are first established

which are employed to analyze the dynamic and static coupling characteristics of the system power. Then

for the dynamic coupling characteristics in the main circuit of the system

the voltage and power angle feed-forward decoupling terms are designed and used for dynamic compensation in the form of decoupling functions

thereby effectively eliminating the dynamic coupling phenomenon caused by power adjustment. Secondly

the virtual electromotive force variation component caused by active power adjustment is calculated to compensate for the voltage droop feedback

reducing its static coupling effect on reactive power. Finally

simulation and experimental results show that the proposed decoupling control method can achieve effective decoupling under the operating conditions of power reference step changes

grid frequency disturbance

grid voltage disturbance

and large power angle

improving the dynamic and static response performance of the system.