Nonsmooth pitchfork bifurcation in a dc-dc converter: coexisting attractors and intermittency

In this paper we deal with the analysis of nonlinear dynamical behavior of a single inductor two inputs two outputs (SITITO) power electronics DC-DC converter. The system can be used to regulate generally two outputs (one positive and one negative). Under certain operating conditions, the switching model can be approximated by a one dimensional piecewise constant vector field and, as a consequence, the corresponding map is piecewise linear (PWL). This model is derived and then it is used to study a nonsmooth pitchfork bifurcation in the system. Coexistence of attractors are detected by using the same model. Intermittent chaotic behavior is also addressed. Analytical results are confirmed by one dimensional and twodimensional bifurcation diagrams.Peer ReviewedPostprint (published version

Dynamics and stability issues of a single-inductor dual-switching DC-DC converter

A single-inductor two-input two-output power electronic dc–dc converter can be used to regulate two generally nonsymmetric positive and negative outputs by means of a pulsewidth modulation with a double voltage feedback. This paper studies the dynamic behavior of this system. First, the operation modes and the steady-state properties of the converter are addressed, and, then, a stability analysis that includes both the power stage and control parameters is carried out. Different bifurcations are determined from the averaged model and from the discrete-time model. The Routh–Hurwitz criterion is used to obtain the stability regions of the averaged (slow-scale) dynamics in the design parameter space, and a discrete-time approach is used to obtain more accurate results and to detect possible (fast-scale) subharmonic oscillations. Experimental measurements were taken from a system prototype to confirm the analytical results and numerical simulations. Some possible nonsmooth bifurcations due to the change in the switching patterns are also illustrated.Postprint (published version