New hybrid-microgrid topology using a bidirectional interleaved converter as a robust power interface operating in grid-connected and islanded modes

Abstract

This study presents a new microgrid topology that uses a bidirectional interleaved converter performing a power interface between DC buses in a hybrid microgrid allowing for both grid-connected and islanded modes. The authors propose a new control strategy and controllers' design method aiming at achieving a high-performance dynamic response regarding the converter load and generation disturbance rejection capability. In the grid-connected mode, the interleaved converter operates in the buck mode providing a high-power-quality DC microgrid voltage. In the islanded mode, the interleaved converter operates in the boost mode and it is responsible for regulating the DC link of the back-to-back converter that connects the main grid to the AC microgrid. A detailed mathematical model is presented to obtain a MIMO system that takes into account the system's disturbances to analyze both stability margins and disturbance-rejection response. Simulations of the proposed topology are carried out in PSCAD/EMTDC in a microgrid operating in grid-connected and islanded operation modes. Experimental results are provided in order to validate the proposed control tuning method.