Extended time - delay autosynchronization for the buck converter

Time-delay autosynchronization (TDAS) can be used to stabilize unstable periodic orbits in dynamical systems. The technique involves continuous feedback of signals delayed by the orbit's period. One variant, ETDAS, uses information further in the past. In both cases, the feedback signal vanishes on the target periodic orbit and hence the stabilized periodic orbit is one of the original dynamical system. Furthermore, this control method only requires the knowledge of the period of the unstable orbit. In general, the amount of feedback gain needed to achieve stabilization varies with the bifurcation parameter(s) of the system, resulting in a domain of control which can be computed without having to deal with the explicit integration of time-delay equations. In this paper we compute the domain of control of the unstable periodic orbits of the buck converter. The simplicity of the nonlinearity of this converter allows us to obtain a closed analytical expression for the curve g : S 1 → C whose index determines the stability. We perform detailed numerical explorations of this index for both period-1 and period-2 orbits for several configurations of the feedback scheme. We run several simulations of the controlled system and discuss the results.