Analysis and Design of N-Phase Current-Sharing Autotuning Controller

Current sensing and sharing are important functionalities for parallel and multiphase power converters. Good current-sensing accuracy and high-performance current-sharing loop design are required for reliable and efficient operation. Therefore, sensing errors and mismatches in the current-sharing loop should be eliminated and calibrated. On the other hand, conventional current-sharing controllers are designed to force equal current sharing or current distribution between power converter phases, which may not result in the most power-efficient operation. An N-phase current-sharing algorithm and controller (NCSAT) with current-sensing autotuning capability is presented in this paper. The presented controller is able to adaptively autotune the current sensing and current sharing between N converter phases that results in achieving current sharing ratio between converter phases for maximum power efficiency. This is achieved without the need for a precise calibration reference or resistor and without the need for any converter´s parameters estimation. The presented controller is also free of sensing inaccuracies and mismatches. The NCSAT controller is analyzed and verified by simulation and experimental results.