Comb filtering assisted proportional-repetitive control achieving zero static error for single-phase inverters

In single-phase inverters, the proportional control is paralleled with the repetitive control to improve the dynamic performances. Meanwhile, in order to guarantee the stability of system, the static error cannot be eliminated in this control. This paper proposed an advanced scheme for the repetitive control to achieve zero error tracking. Taking the advantage of comb filtering by using Fourier transform and its inverse process, the signals on some specific frequencies are selected into repetitive control loops. Comparing with the conventional repetitive control, the new proposed scheme can achieve zero static error without the stability issues. Moreover, it eliminates specific harmonics and lower the total harmonic distribution. Finally, the implementation of this control scheme is quite simple and easy to be realized in a digital controller. The proposed control is verified in both simulation and experimental works.