Power management of an isolated hybrid AC/DC micro‐grid with fuzzy control of battery banks

This study focuses on the development of a supervisory control scheme for power management and operation of an isolated hybrid AC/DC micro‐grid, which consists of an AC micro‐grid and a DC micro‐grid. In the proposed hybrid micro‐grid, wind and diesel generators and AC loads are connected to the AC micro‐grid, whereas photovoltaic array and DC loads are tied to the DC micro‐grid. Moreover, the authors consider two independent battery banks in the AC and DC micro‐grids. Furthermore, the AC and the DC micro‐grids are coupled through a bidirectional converter, which can act as an inverter or rectifier. The objectives of the proposed supervisory controller are listed as follows: (i) maximum utilisation of renewable energy sources along with satisfying the load power demand in both AC and DC micro‐grids, (ii) maintaining state of charge (SOC) of battery banks in both AC and DC micro‐grids and (iii) managing the power exchange between the AC and the DC micro‐grids while the reliability of the whole system is taken into account. The supervisory controller is formalised using a state machine approach. For these purposes, 15 distinct operation modes are considered. Furthermore, in order to extend the battery life cycle, a fuzzy controller manages the desired SOC controlling the charge and discharge currents. The effectiveness of the proposed supervisory controller is evaluated through extensive numerical simulations.