Performance of a coupled inductor for interleaved buck converter with improved step-down conversion ratio

Abstract

This paper proposes a dual-winding coupled inductor (DWCI) based interleaved buck converter (IBC) with improved step-down conversion ratio to improve the ripple in inductor currents and to achieve lower value of the output filter capacitor. The proposed IBC achieves a high step-down conversion ratio by using a switch-capacitor cell. In the continuous conduction mode (CCM), the systematic analysis of ripple current in the windings of DWCI shows the improvement of ripple in inductor current compared to the existing IBCs. Further, the coupling factor of the DWCI reduces the requirement of the minimum value of the output filter capacitor. The operation principle and boundary load condition of the proposed IBC with DWCI are analysed. Furthermore, the small-signal modelling of the proposed IBC with DWCI is investigated. In the voltage-mode control framework, a PI-controller is designed to investigate the sensitivity to the load parameter variation and the performance of the reference output voltage. The proposed converter with DWCI is implemented and experimental results are provided.