Fuzzy Logic based Battery Energy Storage System Control for Frequency Containment

This work proposes the use of a fuzzy logic based controller as a primary frequency controller attached to a battery energy storage system. Besides providing the required active power to stabilize the frequency around the nominal value, the fuzzy controller aims to maintain the battery state of charge as closer as possible to the medium value, thus maintaining available reserve band for both upward and downward regulation. The simulations were performed in Simulink on the classical two-area model frequency model, that includes both primary and secondary control levels. Also, the simulations were done on a 15 minutes (900 seconds) time interval, meant to cover a relevant time interval for all frequency control levels. The BESS is simply modeled by a transfer function, while state of charge calculation, and power and energy limits are considered.