Sensorless current sharing in two-phase input-parallel output-parallel DC-DC converters

This paper introduces a sensorless current-sharing strategy for two-phase input-parallel output-parallel (IPOP) DC-DC converters. A dual active bridge (DAB) DC-DC converter is chosen as the basic DC-DC converter. With this strategy, the parameter mismatches between phases are estimated by perturbing the duty cycle in one phase and measuring the changes of duty cycles in both phases. Then the duty cycles are adjusted to compensate the mismatches, thus achieving current sharing without current sensors. The strategy is verified through both simulation and experimental implementation with a 30V-to-80V, 256W, 20kHz, two-phase IPOP DC-DC converter.