For the two levels of two-way charging machine

a kind of charge/discharge control strategy is proposed based on the virtual synchronous machine(VSM)in microgrid. First of all

the VSM is applied to control the first-level AC/DC converter

while introducing the virtual inertia

damping and excitation to make the charging machine possess the same operation characteristics as the synchronous machine. Secondly

an auxiliary frequency modulation algorithm is designed by using the active power-frequency operation curve to calculate the “correction of the active power reference” and change the power reference

which makes electrical vehicles participate in the primary and secondary frequency regulation of microgrid. Based on the MATLAB/Simulink

the microgrid model with electrical vehicles is developed. The results show that electric vehicles controlled by the proposed strategy can transmit electricity to the power system

which supports the inertia

damping

voltage and frequency

realizes the non-differential regulation of frequency in microgrid at independent mode

and improves the dynamic stability of microgrid.