Consensus control of multiple electric springs considering non-critical load electricity fairness in islanded microgrid

Abstract

Due to the uncertainty of renewable energy source (RES) generation, the islanded microgrid with RESs is prone to voltage and frequency fluctuations. The electric spring (ES) is an effective means to mitigate these fluctuations. However, a single ES may not be sufficient to ensure voltage stability for each node or support system frequency regulation. To address this issue, a consensus control strategy is proposed to coordinate multiple ESs participating in voltage control and frequency regulation. This strategy consists of three layers. The upper layer generates reference voltage and reference angular frequency for each node based on a consensus algorithm. The middle layer calculates d-axis and q-axis components of ES reference output voltage, subsequently synthesizing the reference output voltage of ES. The bottom layer utilizes adaptive sliding mode control to ensure actual output voltage of ES tracks the reference output voltage in real time. This strategy ensures the reactive power output ratio of each ES is equal and that there is consistency in the voltage deviation ratio of each NCL while achieving nodes voltage and system frequency stability.