Odd-harmonic digital repetitive control of a single-phase current active filter

Abstract—Shunt active power filters have been proved as useful elements to correct distorted currents caused by nonlinear loads in power distribution systems. This work presents an all-digital ap-proach, based on the repetitive control technique, for their con-trol. In particular, a special digital repetitive plug-in controller for odd-harmonic discrete-time periodic references and disturbances is used. This approach does not introduce high gain at those fre-quencies for which it is not needed, and thus it improves robustness. Additionally, the necessary data memory capacity is lower than in traditional repetitive controllers. The design is performed for the particular case of single-phase shunt active filter with a full-bridge boost topology. Several exper-imental results are also presented to show the good behavior of the closed-loop system. Index Terms—Current harmonics compensation, digital repeti-tive control, PWM converters, sampled-data control, shunt active filters. I