Secondary Frequency and Voltage Regulation for Inverter-Based Microgrids: A Sparsity-Promoting DAPI Control Approach

This brief developed a novel sparsity-promoting distributed averaging-based proportional-integral (DAPI) control approach for secondary frequency and voltage regulation in inverter-based microgrids (MGs). In order to enhance the resilience of DAPI controllers and save communication resources, the metric “sparsity” needs to be fully considered without weakening its robustness to load fluctuations when designing the Laplacian matrix. To this end, in our work, a sparsity-promoting optimal linear output-feedback control problem is constructed, and an optimization framework is proposed by minimizing the impact of load fluctuation and cardinality function of the Laplacian matrix. Moreover, the optimization problem is flexible with its constraints which guarantee the basic properties of the Laplacian matrix for DAPI controllers. To solve the optimization problem, an alternating direction method of multipliers (ADMMs) is also developed, and the Laplacian matrix is then obtained. Furthermore, extensive case studies have shown that our approach can reduce the communication links of DAPI controllers effectively, and the robustness of voltage and reactive power sharing to load fluctuations is not weakened.