Integration of Sodium Metal Halides Batteries in Microgrids for Providing Active Filtering Services

This paper investigates active filtering services provided by Sodium Metal Halides Battery (SMHB) that acts as power/energy source and an Active Filtering System (AFS) at the same time. The proposed AFS is achieved by interfacing SMHB with a Four-Leg Voltage Source Inverter (4L-VSI) through an LC filter, which has to be designed and sized properly. In this regard, this paper presents a suitable sizing criterion for the LC filter in order to prevent SMHB from handling fast and sudden current variations, minimizing DC-link voltage ripple at the same time. The proposed sizing criterion is defined based on simplified SMHB model at first; it is then validated through numerical simulations, which refer to a more advanced SMHB model that has been derived experimentally.