The goal of this paper is to control the dynamics of an islanded microgrid, a small-scale power system with distributed generation. An islanded microgrid is disconnected from the larger, main grid, and must maintain voltage and frequency standards using only local generation. As a result, islanded microgrids are more vulnerable to fluctuations in power supply and demand; this is especially relevant for intermittent renewable sources like wind turbines.
The system is stabilized with static-output-feedback ℋ∞ γ-suboptimal control. This is a multiple-input multiple-output (MIMO) controller in which the measured data is used as the direct input to a static gain matrix, whose output is in turn used to control the closed-loop system. In order to judge the performance of the decentralized controllers, the micgorid is controlled first in a centralized manner, where each controller has access to all measured state variables. Decentralized controllers are then synthesized by casting the problem as a convex program, where each controller only has access to locally measured variables. Control performance is compared with respect to a switched-on wind turbine, where we see that the decentralized controller effectively mitigates the system disturbance due to the renewable intermittency.
