Analog circuits to implement a repetitive controller for harmonic compensation

In this paper, simple analog circuits lo implement a repetitive control scheme are discussed. The repetitive control has shown to be a useful tool for tracking of periodic reference signals and for compensation of periodic disturbances. The main advantages of the proposed circuitry are: (a) no digital conversion is required, (b) easy tuning to the corresponding frequency, and (c) cost effective. A description of the circuits and corresponding experimental frequency responses are given.