Distributed control of multiple Electric Springs in microgrids

The microgrid´s control strategies are designed to achieve the power sharing, as well as to regulate voltage and frequency within acceptable ranges. To fully meet these requirements, a distributed cooperative control strategy for multiple Electric Springs (ESs) is proposed in this paper. By ensuring the reactive power utilization ratio of each ES to converge to the given set point, the tradeoff between the reactive power sharing accuracy and the requirement of the voltage regulation can be satisfied with desirable dynamic response. Based on the graph theory, the proposed cooperative control strategy is designed with a sparse communication topology, which only requires limited local communication. As a result, the cooperative control among a large number of ESs can be realized. Under the fault condition, the case study demonstrates that the proposed methods can reach the control objective, i.e., adjusting the voltage level of critical loads with prompt dynamic response.