Adaptive Sliding Mode Controller for Real Time Frequency Stabilization of Standalone Microgrid System

Abstract

Microgrids are miniature versions of power grids with distinct operation characteristics. These microgrids can operate independently in stand-alone mode or work together with the larger grids in grid-connected mode. Power grids must operate within the prescribed frequency which could be achieved by appropriately handling the power generation and demand of the grids. In a microgrid system, frequency stabilization is the process of sustaining the frequency within acceptable ranges around the nominal value even in many conditions, including fluctuating power demand, unanticipated losses of one or more of the system s generating units, and intermittent source supplies. The thesis aims to achieve frequency stabilization with a sliding mode controller (SMC) for a standalone microgrid system. The four different architectures of the microgrid systems are developed with solar, wind, diesel generators, and energy storage systems as the sources. The systems are tested under various operation conditions like dynamic loading operations and multiple source variations. The proposed controller has proven reliable and effective in controlling the system s frequency in every dynamic scenario. The prescribed control method and the microgrid model have been designed in MATLAB Simulink, and the system is validated in the OPAL-RT environment by implementing the model in software in loop (SIL). Whereas SIL is an excellent tool like hardware in the loop and it helps to accelerate the development cycle faster in hardware implementation.