Repetitive controller, control method thereof and feedback control system

A repetitive controller, a control method thereof and a feedback control system are disclosed. The repetitive controller includes an internal model section, a periodic delay module and a compensation module. An input quantity is input into the repetitive controller via an input terminal of the internal model section; the internal model section, the periodic delay module and the compensation module are connected in series. The repetitive controller further includes a particular frequency selection and passing module, connected in series with the internal model section, the periodic delay module and the compensation module or configured on a forward path of the internal model section. In the repetitive controller of the disclosure, a particular frequency selection and passing module is incorporated such that only the harmonic at the selected frequency are filtered out, thereby realizing the function of removing the harmonic at the particular frequency.