Master’s thesis – Modelling and control of sustainable microgrid

In recent years, numerous research and development projects have been carried out in the field of renewable energy sources (RES), which has entailed an increase in the penetration of power generated by intermittent plants into the grid. In electricity systems, a microgrid coupled with RES can lead to significant economic and environmental benefits. However, it is necessary to compensate for all the problems caused by the stochastically variable nature of RES. The main problems of these microgrids are associated with the unpredictable imbalance of power generated by RES (as a consequence of varying weather conditions), but also by the variability of energy consumption. The aim of this thesis is to study a microgrid with distributed generation units coupled to an energy storage system and featuring connection capabilities to the main grid as a backup solution. Specifically, the units consist of a photovoltaic system, a wind turbine and a fuel cell, and an alkaline electrolyser for hydrogen production coupled with a tank, which can be used as an energy storage system. A control strategy is to be developed and implemented. Dynamic models for all components of the microgrid are to be designed, validated and assembled into an overall model, building upon which it will be possible to design a strategy for reducing power absorption from the grid whenever weather conditions are favourable. The featured photovoltaic plant can (for example) operate according to the maximum power point tracking principle, whereas the wind turbine will typically operate between its cut-in and cut-out speeds. When the power supplied by these units is greater than the requested load, it is possible to charge the storage system (hydrogen tank) and/or to exchange energy with the grid. Similarly, during unfavourable environmental conditions, demand could be met by the energy produced by the fuel cells, reducing grid absorption.