H_∞ and gain scheduled H_∞ control for islanded microgrids

Control strategies for sources in microgrids are pervasive in the literature. Droop control has received a great deal of attention as it requires no communications with other sources in the network. Droop control is typically synthesized by considering an entire network, implemented as a pair of constant gain controllers, and may suffer from poor performance and limited operating range. Since networks of sources can become quite large and are subject to change, a simplified approach to modeling and robust control are needed. In this paper H_∞ and gain scheduled H_∞ controllers are synthesized using Glover McFarlane loopshaping. It is shown that the H _∞ approach produces superior robustness and performance compared to the traditional approach to droop control using constant gains. The H_∞ and constant gain controllers are also compared using hardware.