Stability Analysis of Multi-Phase Synchronization in Paralleled Buck Converters With Winner-Take-All and Loser-Take-All Switching Rules

This paper studies paralleled systems of buck converters with two kinds of switching rules. First, the system is controlled by the winner-take-all and current threshold switching rules. The system can generate stable multi-phase synchronization of inductor currents. As parameters vary, the multi-phase synchronization loses stability and the system exhibits a chaotic phenomenon in which unstable multi-phase synchronization is embedded. Second, the system is controlled by winner-take-all and loser-take-all switching rules. The system can generate stable multi-phase synchronization in a wide range of parameters: it is suitable to realize current-sharing and ripple reduction for low-voltage-high-current capabilities. In order to analyze the dynamics, we present simple piecewise linear models. Using the piecewise exact solutions, we prove stability of the synchronization phenomena and give a condition of parameters for the stability. We can also investigate the ripple characteristics precisely. Presenting simple test circuits, the stable synchronization phenomena are confirmed experimentally.