Analysis of subharmonic oscillations in a ferroresonant circuit

Ferroresonance is a nonlinear oscillatory phenomenon that occurs in capacitively coupled transformers or reactors under certain conditions. In this paper, an averaging method is utilized to compute the domain in 2D parameter space where subharmonic (period-3) ferroresonant oscillations could persist. The accuracy of the analytical results is verified using numerical simulations and the power spectral density. It is shown that the proposed method yields a quick means to determine (i) the proximity to initiation of subharmonic resonance and (ii) the effect of core loss on the domains of subharmonic oscillations.