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

• The existing multi-ES control methods rarely consider the state of non-critical load (NCL), which may lead to over-response of some NCL and even functional failure. To solve these problems, we propose a consensus control strategy that coordinates multiple ESs participating in node voltage control and system frequency regulation. • The proposed strategy consists of three layers. By introducing a voltage observer for each ES, the upper layer of this control strategy acquires the global average voltage estimated values for each ES. The middle layer is responsible for generating the ES reference output voltage. The bottom layer is responsible for making the actual output voltage of ES track its reference output voltage in real time based on ASMC. • The simulation results show that this control strategy can not only achieve voltage stability for each node and system frequency regulation, but also keep the voltage deviation ratio of each NCL consistent, ensuring the fairness of electricity consumption and operational safety for all NCLs. 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.