When the grid voltage is unbalanced

the output negative sequence current of synchronverter in grid-connected operation causes serious unbalance of three-phase grid-connected current

and this situation further aggravates the instability of power grid and restricts its application in the new energy grid connection. In response to this problem

the mechanism of unbalanced current caused by the grid voltage and inverter output voltage being unsynchronized is analyzed

then a novel method to suppress the negative sequence current is proposed. Firstly

the output current of synchronverter is predicted to foresee current situation information in advance. Secondly

the value of voltage which is calculated by the differential current value from situation prediction is imported to synchronous control system to realize real time compensation. This method can realize preventive control quickly by situation orientation. The simulation results show that the proposed method can effectively restrain the negative sequence current

reduce current unbalance

and improve the dynamic performance of the control system.