Correlative zero-phase fundamental component notch filter for power signals

The paper deals with a correlation based, fundamental component notch filter targeted for power signals. Due to prediction built-in into the filtering algorithm the filter delivers zero-delay analog output signal which can be directly used to control active harmonics compensators. Active harmonics compensators used in power system require power system synchronized controlling signals in which the fundamental component is removed or recalculated. Nondelayed filter answer cannot be assured with classical analog (and digital) filtering. In the presented filter solution, it is obtained by direct subtraction of the predicted fundamental component from the processed signal. Real time, no delay, fundamental analog signal component is extracted by the A/D-DSP-D/A signal filtering module. The DSP of the module performs the orthogonal signal analysis and synthesis. Filter solution is presented and filtering properties important from the application point of view are discussed.