Robust Networked Control Scheme for Distributed Secondary Control of Islanded Microgrids

Distributed secondary control (DSC) is a new approach for microgrids (MGs) by which frequency, voltage, and power can be regulated by using only local unit controllers. Such a solution is necessary for anticipated scenarios that have an increased number of distributed generators (DGs) within the MG. Due to the constrained traffic pattern required by the secondary control, it is viable to implement a dedicated local area communication functionality among the local controllers. This paper presents a new wireless-based robust communication algorithm for the DSC of MGs. The algorithm tightly couples the communication and the control functionality, such that the transmission errors are absorbed through an averaging operation performed in each local controller, resulting in a very high reliability. Furthermore, transmissions from each DG are periodic and prescheduled broadcasts, and in this way, contention over the shared wireless medium is avoided. Real-time simulation and experimental results are presented in order to evaluate the feasibility and robustness endowed by the proposed algorithm. The results indicate that the proposed algorithm is very robust with respect to communication impairments, such as packet delays and random packet losses.