Noise-induced and border-collision-induced bubbling

Suddenly appearing high-frequency low-amplitude phase-restricted oscillations disturbing the waveform of signals in many kinds of power converters, also known as bubbling, have been recently shown to appear not at the points of smooth bifurcations, as previously assumed, but soon after. In the present work, we investigate further reasons for the onset of bubbling. We show that the presence of long phase intervals associated with expanding functions modeling the system’s behavior leads to a strong amplification of any kind of disturbances, causing noise-induced bubbling to appear both in physical experiments and in numerical simulations. Furthermore, we show that the onset of bubbling may be caused by persistence border collision events.