Robust Mixed $\mu$ -Synthesis Frequency Regulation in AC Mobile Power Grids

This article proposes a novel controller for the secondary load frequency control (LFC) of an alternating current shipboard microgrid (MG). The suggested controller is based on the robust <inline-formula> <tex-math notation="LaTeX">$ {\mu }$ </tex-math></inline-formula>- and mixed <inline-formula> <tex-math notation="LaTeX">$ {\mu }$ </tex-math></inline-formula>-synthesis in which the structured system uncertainties and external disturbance inputs are considered in the design procedure of the controller. The offline designed controller is resilient against the power fluctuations of the load and renewable energy sources (RESs), such as solar and wave energies. The output of the controller manipulates a diesel generator, as well as energy storage systems (ESSs) to effectively regulate the frequency of the ac MG to the desired value and reduce the frequency oscillations originated by the loads and RES power changes. Several hardware-in-the-loop (HiL) real-time dSPACE emulator-based simulations have been performed to show the effectiveness of the suggested robust control scheme. In addition, the comparison results are provided to better highlight the advantages of the proposed <inline-formula> <tex-math notation="LaTeX">${\mu }$ </tex-math></inline-formula>-synthesis-based approach over the state-of-the-art techniques.