The small signal model of distribution static synchronous compensator based on the ultra-capacitor energy storage is established and the decoupling control is achieved on the system side of ultra-capacitor energy storage system and the side of static synchronous compensator of distribution grid by the use of power forward feed decoupling method. The bi-direction DC/DC converter using the control method of single closed-loop and double closed-loop control method is designed for distribution static synchronous. It is simulated and verified by Matlab that DSTATCOM /UCES can effectively improve the temporary rise and drop of voltage of distribution grid and

at the same time

the correctness of the controller model is analyzed.