A new quasi Newton filtering technique for power system frequency estimation and harmonics/interharmonics rejection

This paper presents a new technique to estimate power system frequency and peak value of current/voltage waveforms based on the quasi Newton (QN) technique. The QN method is used to implement a nonlinear filter which estimates power system frequency, rejects harmonics/inter-harmonics, and track the peak value of the voltage/current waveform. The performance of the proposed technique in presence of harmonics, inter-harmonics, dc offset, and power electronics switching operation has been evaluated by presenting a selection of simulation results.