Mitigation of negative impedance instabilities in a three phase interleaved boost converter feeding constant power load

An interleaved converter consists of multiple phases operating out of phase with the well known benefits of reduced input output current and ripples, improved efficiency and better thermal performance. When the interleaved converter is connected to a constant power load, its negative incremental impedance characteristics leads to instability. This leads to an increased oscillation in the DC link voltage and the source current which is interfaced with the interleaved converter. In this manuscript, a robust control consisting of the sliding mode control is proposed to damp the oscillations due to CPL and maintain the DC link voltage and source current within the permissible desired limits. The proposed sliding manifold consists of the power error terms and a voltage error term. The proposed control performance is validated through simulation and experimental results on a 500W three phase interleaved boost feeding a buck converter fed resistive load setup.