Realisation of a lithium-ion battery model for microgrid applications and validation with real-time simulation platform

Litihium-ion battery is a relatively new technology that was first commercialized in 1991. Since then, litihum-ion batteries have been mainly used for small portable technologies such as phones and computers. As it is a new technology, it has been constantly improving over the past few years, resulting in lower cost and better performances. Lithium-ion batteries are now widely used in electric vehicles and there is thus a strong incentive for car companies to further improve this technnology. In addition to that, perspectives of using Li-ion batteries for grid applications have opened up. In fact, investements in renewable energy sources are increasing, with particular attention to wind and solar power plants. The intermittence of theses resources requires high energy efficiency storage systems. At the same time, the emergence of distributed energy resources (DER) has stimulated research into new ways of organizing the electrical grid. Microgrid technologies have attracted increasing attention as an effective mean of integrating such DER units into power systems. A microgrid is defined as a group of interconnected loads and distributed energy resources within clearly defined electrical boundaries that can connect and disconnect from the main grid to enable it to operate in both grid-connected or island mode. Whereas traditional power grids are very centralized with power flowing from large synchronous generators connected in high voltage, microgrids appear as a way to organize the electrical grid in a more decentralized manner with DER connected in low voltage. By using local control, the intermittency of renewable sources can be better compensated. Moreover, in case of power outage in the main grid, a microgrid can disconnect and provide power for the local loads. It can thus give an improved level of power quality and reliability for end-users. However, microgrids with an important share of renewable sources need enery storage systems (ESS) to provide these features. Several technologies of ESS are available, among which Li-ion battery is one of the most promising. In this context, this master's thesis presents a complete model of Li-ion battery energy storage system (BESS). This model includes the Li-ion battery itself, as well as the different filters, converters and controllers. The emphasis of the model is placed on the dynamic performances in order to study how the designed BESS can help to support a microgrid. On top of that, the robustness of the BESS against grid perturbations is tested as well as power quality considerations. The model was built and tested with Matlab Simulink. It was also successfully tested on a real-time simulation platform, which validates the feasability of the controllers. The simulations results show that BESS, thanks to their fast response time, can effictively help to support a microgrid against perturbations. Specifically, the BESS was included in a simple microgrid and tested as a frequency regulation reserve (virtual inertia and primary reserve). Furthermore, with a proper design of filters and controllers, the BESS is robust against harmonics, unbalance and provides good power quality