Hybrid least-square adaptive bacterial foraging strategy for harmonic estimation

Harmonic estimation for a signal distorted with additive noise has been an area of interest for researchers in many disciplines of science and engineering. A new algorithm is presented, based on the foraging behaviour of E. coli bacteria in our intestine to estimate the harmonic components present in power systems voltage/current waveforms. The basic foraging strategy is made adaptive, depending on the operating condition, to make the convergence faster. The harmonic estimation is linear in amplitude and nonlinear in phase. As the proposed algorithm does not rely on Newton-like gradient-descent methods, it is used for phase estimation whereas the linear least-square scheme estimates the amplitude, thereby presenting the hybrid method. The improvement in percentage error as well as the processing time compared to the conventional genetic algorithm method is demonstrated. The percentage error in this new algorithm is less than 7% at 0 dB signal-to-noise ratio for Gaussian noise. The performance is quite acceptable even in the presence of decaying DC component as well as changes in amplitude and phase angle of harmonic components.