Zero Average Surface Controlled Boost-Flyback Converter

Abstract

The boost-flyback converter is a DC-DC step-up power converter with a wide range of technological applications. In this paper, we analyze the boost-flyback dynamics when controlled via a modified Zero-Average-Dynamics control technique, hereby named Zero-Average-Surface (ZAS). While using the ZAS strategy, it is possible to calculate the duty cycle at each PWM cycle that guarantees a desired stable period-1 solution, by forcing the system to evolve in such way that a function that is constructed with strategical combination of the states over the PWM period has a zero average. We show, by means of bifurcation diagrams, that the period-1 orbit coexists with a stable period-2 orbit with a saturated duty cycle. While using linear stability analysis, we demonstrate that the period-1 orbit is stable over a wide range of parameters and it loses stability at high gains and low loads via a period doubling bifurcation. Finally, we show that, under the right choice of parameters, the period-1 orbit controller with ZAS strategy satisfactorily rejects a wide range of disturbances.

Boost‐flyback converter: Experimental assessment of recent control techniques

“…During steady operation, the BF converter dynamically switches between different topologies in a sequential manner, forming a periodic orbit that oscillates around the desired output voltage . The stability of these periodic orbits has been extensively studied in previous papers 19,24,33,34 . In this work, our focus is on the steady operation of the periodic orbit defined by the sequence of topologies as it is the solution that best fits the experimental parameters used in this work, and has also shown to be more robust in previous findings.…”

“…The stability of these periodic orbits has been extensively studied in previous papers. 19,24,33,34 In this work, our focus is on the steady operation of the periodic orbit defined by the sequence of topologies T A B L E 1 Combination of the values in the non-linear elements leading to the 6 admissible topologies.…”

“…To achieve the desired output, two different control techniques that have been theoretically proposed in recent works 19,24 are used and will be summarized in the following section.…”

“…This function is forced to be zero at every period T, thereby achieving a fixed switching frequency. This approach, known as the zero average surface (ZAS) strategy, has been extensively studied in Muñoz et al, 24 and it is a variation of ZAD control, which has been thoroughly examined in numerous papers. [25][26][27][28][29][30][31][32] Through numerical experiments, it was found that the ZAS strategy also effectively regulates the output and rejects disturbances.…”

Fuel Cell Voltage Regulation Using Dynamic Integral Sliding Mode Control

“…Another technique, called zero average dynamics (ZAD), was utilized in [49,50], where the goal was to find a duty cycle that corresponds to the zero average value of the dynamics of the selected sliding manifold. This allows the switching rate of the steady state to be configured as desired, resulting in a performance average which is near the ideal behavior.…”