The virtual synchronous generator(VSG)control can be realized by adding inertia and damping in the inverter

which can improve the stability of the AC bus frequency while considering the smooth switching of the local load. The load of parallel VSG can be distributed reasonably according to its capacity ratio

but the different impedances will cause steady-state error of parallel system

and also affect its dynamic performance. To solve this problem

a parallel VSG control method based on virtual impedance is proposed. Firstly

the improved excitation is proposed which can control the AC bus voltage

and operation characteristics of active power and reactive power are analyzed. Secondly

the impedance matching principle is obtained while adding the virtual impedance

and the effect of virtual impedance in transient process is analyzed. Finally

the proposed control strategy is verified in the environment of MATLAB/Simulink and the experimental platform. The results show that the proposed strategy can inhibit the frequency fluctuation in cutting process and improve the stability of VSG parallel system.