The multi-functional grid-connected inverter can improve power quality while used to transmit active power. To make the inner loop controller track reference current fast and accurately

a new design method of inner loop controller based on the modified repetitive control algorithm is proposed. The modified repetitive controller is composed of a proportional controller and a traditional repetitive controller connected in parallel

and an equivalent controlled object is used for analyzing the stability

steady state error and dynamic performance of the inner loop control system and designing the parameters of the modified repetitive controller. Finally

simulations and experiment results show that the proposed inner loop controller can track reference current fast and accurately

and multi-functional grid-connected inverter based on the modified repetitive control algorithm has an excellent ability to enhance power quality. This work is supported by National Natural Science Foundation of China(No. 51577128).