Optimal Dynamic Harmonic Extraction and Suppression in Power Conditioning Applications

Power quality in electrical systems is a basic requirement that should be guaranteed. Nonetheless, the increase of power-electronics-based applications and other nonlinear loads have induced harmonic distortion degrading the power quality; therefore, effective methods to measure and suppress such distortion need to be developed. The main contributions of this article are the following: the development of a novel fast-converging optimal estimator to determine online the harmonic components of a time-varying signal, which can be used for analysis and control purposes; the usage of the estimator to generate reference signals for an optimal control system in order to suppress the harmonics components; and the experimental validation of the proposed methodology as a feasible solution for industrial applications. The proposal considers practical assumptions such as the signal to be analyzed is corrupted with noise and contains time-varying harmonics (i.e., no steady-state condition is assumed). As an application of the harmonic estimator, the following two experimental tests are carried out: first, the optimal determination of the harmonic components of the current waveform in a nonlinear load, and second, the usage of harmonics information to mitigate them through of an active power filter, which is controlled by using an optimal trajectory tracking control scheme.