Abstract：Considering that the problem of voltage fluctuations on the DC side caused by the three-phase

imbalance of the AC grid of the flexible interconnection device，a DC voltage fluctuation suppression strategy for

flexible interconnection device based on the Torricelli point was proposed. Firstly，by defining the Torricelli point

of the triangle formed by the voltage vector in the three-phase unbalanced fault system as the "new neutral point"，

the voltage amplitude asymmetry and phase angle drift faults in the traditional three-phase coordinate system were

transformed into voltage amplitude faults in the Torricelli point coordinate system；secondly，the relationship

between the active power oscillation of the three-phase power system and DC fluctuations was analyzed，a new

control strategy was established to suppress the voltage fluctuations of the DC bus voltage by suppressing the

fluctuation of double frequency component of active power effectively. Finally，the proposed method was proved to

be effective by the Matlab/Simulink simulation model.

      Key words：Torricelli point；flexible interconnected；asymmetric failure；voltage fluctuation