Optimum State-of-Charge Operating Range for Frequency Regulation of Energy Storage Systems Using a Master–Slave Parallel Genetic Algorithm

Abstract

Lithium batteries are used for frequency regulation in power systems because of their fast response and high efficiency. Lithium batteries have different life characteristics depending on their type, and it is necessary to set the optimal state-of-charge (SOC) operating range considering these characteristics to obtain the maximum gain. In general, narrowing the operating range increases the service life but may lower the performance of charging and discharging operations in response to frequency fluctuations, and vice versa. We present performance assessment indicators that consider charging and discharging due to frequency variations and lifespan of the batteries. However, to evaluate the performance, while reflecting the non-linear life characteristics of lithium batteries, simulating the entire operation is necessary, which requires a long calculation time. Therefore, we propose a master–slave parallel genetic algorithm to derive the optimal SOC operating range with reduced calculation time. A simulation program was implemented to evaluate the computational performance that determines the optimal SOC range. The proposed method reduces the calculation time while considering the non-linear life characteristics of lithium batteries. It was confirmed that a more accurate SOC operating range could be calculated by simulating the entire life span.

Research on photovoltaic energy storage unit charge state detection method based on improved limit learning machine

“…The PCA method has been shown to be more efficient in detecting the degradation of the battery's health through experimental realization analysis. Literature [18] designed a master-slave parallel genetic algorithm to increase the computational effort to obtain the optimal SOC operating range, which was evaluated in a simulation program to corroborate that the altered algorithm can stably simulate the full life of the battery and compute the accurate SOC range. The challenges that battery components face, particularly the ionic and electronic conductivity and resistance related to electrode/electrolyte in solid-state electrolytes (SSE), were discussed in Literature [19].…”

Evaluation of Quadrature Signal Generation Methods with Reduced Computational Resources for Grid Synchronization of Single-Phase Power Converters through Phase-Locked Loops

“…Some relevant examples are the charging points for electric vehicles [4] and the power supply for railway transportation [5]. The raising of renewable generation such as photovoltaic [6] and wind [1] along with energy storage plants [7] also benefits from the power converter interfaces. The energy distribution systems also leverage their capabilities.…”