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 multi-phase dc-dc converters implementing current-mode control. Only one current sensor at the dc-link is required to measure and reconstruct the phase currents. Multiple current samples in the PWM 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, 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.