An islanded hybrid microgrid design with decentralized DC and AC subgrid controllers

This study introduces integration of wind plants, solar panels, and fuel cell plants to comprise a hybrid microgrid (MG). The energy conversion process of wind plant and fuel cell is managed by a conventional PI controller while output voltage of solar plant is controlled by an enhanced perturb and observe (PO) maximum power point tracking (MPPT) algorithm with PI regulator. The designed controllers are analysed for each power plant considering varying conditions. The wind speeds have been arbitrarily adjusted to random values between 5 ms and 12 ms for each wind turbine. On the other hand, irradiation values applied to PV plant have been varied between 500 W/m2-1300 W/m2 in order to analyse the efficiency of MPPT controller. It is verified that the proposed PI-PO MPPT controller robustly stabilizes output voltage comparing to conventional PO MPPT controller. The identical MPPT controller has been used to control fuel cell stack. The analysis results and proposed controllers are presented in detail. The technical specifications of the sources, and control methods of the power converters can be easily modified and the comparisons among others can be performed to increase the understanding on MG and RES operating conditions.