Calculation of the Proper Auxiliary Circuit Phase Number for Multiphase Stacked Interleaved Buck Converters

A multiphase stacked interleaved buck converter (SIBC) ensures the cancellation of current ripple across all duty cycles. However, to achieve ripple cancellation, the auxiliary circuit in the multiphase SIBC must operate at a higher switching frequency than the main circuit. In this paper, we propose a calculation method to determine the proper number of auxiliary circuit phases in multiphase SIBCs, aiming to reduce the switching frequency of the auxiliary circuit by increasing its phase configuration. The effects of the auxiliary circuit phase number on output current ripple, inductor volume index, and DC-blocking capacitor requirements of the multiphase SIBC are also analyzed. The proposed phase number for the auxiliary circuit is validated through simulation, with a focus on output current ripple cancellation.