Construction of frequency regulation RESS based on advanced cell grouping combined with the DWT

This approach newly gives insight to the design and implementation of an advanced lithium nickel cobalt aluminum oxide (LiNoCoAlO2 or NCA) cell grouping combined with the discrete wavelet transform (DWT) for frequency regulation renewable energy storage system (RESS) in grid-connected application. For an advanced NCA cell grouping, the discharge capacity and two open-circuit voltages (OCVs) before and after capacity measurement, and hybrid pulse power characterization (HPPC)-based resistances at a specific state-of-charge (SOC) point are firstly measured. The most important thing in this approach is to consider the discrete wavelet transform (DWT) as the major role, especially high-frequency component decomposed by the DWT-based multi-resolution analysis (MRA), for frequency regulation RESS. According to this proposed approach, it can be absolutely expected to reduce cell-to-cell voltage and SOC imbalances in the tray and to have an efficient RESS in grid-connected application.