The control systems of grid-connected inverters with LCL filter based on “proportion-integration (PI) and repetitive control” are analyzed in detail. And it is pointed out that its dynamic performance has yet to be further improved and its compensation function form is complex while difficult to achieve. By using the zero phase error tracking control and disturbance observer (DOB)

an improved repetitive control strategy is proposed. The use of the zero phase error tracking control can improve the dynamic performance of the system and its compensation function can be easily designed. On the other hand

the use of DOB can overcome the parameter dependence shortcomings of zero phase error tracking control. Finally

simulations and experiments show that

compared with “PI and repetitive control”

the proposed control strategy can yield a better dynamic performance and

while ensuring the steady-state control accuracy

it also has the advantage of strong robustness.