When an asymmetric fault occurs in the grid

the cascaded static synchronous compensator（STATCOM） still needs to output symmetrical current to maintain the stability of the system. At this time

the traditional grid voltage feed-forward strategy will lead to unbalanced active power among three phases

which will cause a large imbalance of DC voltage between the three phases

seriously affecting the safe operation of the system. To solve this problem

a new grid voltage feed-forward strategy is proposed in this paper. In the strategy

the neutral point of the traditional proportional feed-forward voltage is moved to the positive isogonal center of the triangle formed by the grid voltage

so that the output voltage and current of the converter are perpendicular to each other. Thus

the active power exchange between the three phases of the cascaded STATCOM is greatly reduced

and the stability of the DC voltage under asymmetric faults is effectively improved. Simulation and experimental results verify the effectiveness and feasibility of the proposed control method.