Open Access

ARTICLE

Variable Integral Parameter Control Strategy for Secondary Frequency Regulation with Multiple Energy Storage Units

Jinyu Guo^*, Xingxu Zhu, Zezhong Liu, Cuiping Li

Key Laboratory of Modern Power System Simulation and Control & Renewable Energy Technology, Ministry of Education (Northeast Electric Power University), Jilin, 132012, China

* Corresponding Author: Jinyu Guo. Email:

Energy Engineering 2025, 122(10), 3961-3983. https://doi.org/10.32604/ee.2025.067811

Received 13 May 2025; Accepted 16 July 2025; Issue published 30 September 2025

Abstract

In high-renewable-energy power systems, the demand for fast-responding capabilities is growing. To address the limitations of conventional closed-loop frequency control, where the integral coefficient cannot dynamically adjust the frequency regulation command based on the state of charge (SoC) of energy storage units, this paper proposes a secondary frequency regulation control strategy based on variable integral coefficients for multiple energy storage units. First, a power-uniform controller is designed to ensure that thermal power units gradually take on more regulation power during the frequency regulation process. Next, a control framework based on variable integral coefficients is proposed within the secondary frequency regulation model, along with an objective function that simultaneously considers both Automatic Generation Control (AGC) command tracking performance and SoC recovery requirements of energy storage units. Finally, a gradient descent optimization method is used to dynamically adjust the gain of the energy storage integral controller, allowing multiple energy storage units to respond in real-time to AGC instructions and SoC variations. Simulation results confirm the effectiveness of the proposed method. Compared to traditional strategies, the proposed approach takes into account the SoC discrepancies among multiple energy storage units and the duration of system net power imbalances. It successfully implements secondary frequency regulation while achieving dynamic power allocation among the units.

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Keywords

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