The combination of proportional-integral (PI) and repetitive control strategy for the distribution static synchronous compensator (DSTATCOM) is able to improve the compensation accuracy of reactive power and harmonic and suppress the low-order harmonic in the output current generated by itself due to dead time

grid harmonic

etc. In order to eliminate the effect of fundamental delay caused by the controller and improve the dynamic performance and stability

the optimal repetitive control based on error adjustment and the advanced internal model is designed. The input signal of the repetitive controller is dynamically regulated by hysteresis and attenuator according to the error amplitude of the reactive axis. It can reduce the influence of the repetitive controller on the feed-forward path and improve the response speed. According to the harmonic characteristics of the three-phase grid in the synchronous rotating coordinate

the advanced internal model is introduced to reduce the cycle delay to improve the response speed and stability. Simulation and experimental results have verified the feasibility and practicality of the method. This work is supported by National Natural Science Foundation of China (No. 51177147) and Zhejiang Key Science and Technology Innovation Group Program (No. 2010R50021).