A dynamic harmonic observer for active power filter to suppressing harmonics in distribution networks

A large number of power electronic devices such as inverters, converters, and rectifiers are being integrated into the entire distribution system through sources, grids, and loads. Consequently, the issue of harmonic pollution is becoming increasingly severe. This paper proposes a dynamic harmonic observer for enhancing the performance of Active Power Filters (APFs) in harmonic suppression. Firstly, an estimation model based on the Taylor series expansion on the time-varying amplitudes and phase angles is established. Secondly, the estimation filter bank is generated in the least-squares sense. Finally, the dynamic harmonic observer is achieved by removing the waveform of the fundamental component estimated using the generated estimation filter bank. Simulation in MATLAB/Simulink demonstrates the ability of the proposed dynamic harmonic observer to accurately and dynamically track harmonic components which provides the reference harmonic signal in APF. The results validate the effectiveness and practicality of the proposed dynamic harmonic observer in enhancing APF performance of suppressing harmonics.