Robust Controller for Community Microgrids for Stability Improvement in Islanded Mode

Abstract

Many utilities are developing microgrids to improve power reliability and grid resiliency for customers. One critical challenge in microgrid design is maintaining system stability with changing operating conditions in the microgrid. The technical and contractual constraints of accessibility and controllability to customer-owned resources limit available control options. This paper details a single-phase community microgrid model and illustrates the stability challenges. It further proposes adopting an optimal controller using predictive current control (PCC) and robust control mu-synthesis to improve microgrid stability in islanded operating mode. Incorporating the mu-synthesis in the controller design assures the microgrid's robust stability. The proposed method facilitates the incorporation of main uncertainties in the microgrid: change in resources, uncertainties in their modeling, and load variation. The proposed method overcomes the constraints and does not impact the customer's resources normal operation. Furthermore, the controller has a simple structure and is easy to implement. The simulation results validate that the designed controller can maintain the system stability and achieve optimal performance against various changes in the microgrid. This paper presents a practical solution to the challenges utilities are facing in microgrid development.