An Active Current Reconstruction and Balancing Strategy With DC-Link Current Sensing for a Multi-phase Coupled-Inductor Converter

This paper proposes an active technique to reconstruct and balance the phase currents in multiphase dc-dc converters implementing both of voltage- and current-mode controls. Only one current sensor at the dc link is required to measure and reconstruct the phase currents. Multiple current samples in the pulsewidth modulation switching period are synchronized with the carrier waveforms to actively reconstruct the phase currents using a simple active balancing algorithm that is implemented in a digital controller. The proposed technique improves system performance, stability, and efficiency, and prevents inductor saturation. A 5-kW four-phase dc-dc converter prototype for battery charging application is built to experimentally verify the proposed algorithm.