Robust Control of Grid-Tied Inverter with LC Filter via Adaptive FCS-MPC Cost Function Optimization

In this paper, a robust model predictive control for <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$3-\phi$</tex> grid-tied inverter with LC filter is presented. The overall control architecture is made up of two interconnected control loops. The outer loop, based on <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{H}_{\infty}$</tex> control, regulates grid current in the event of system parameter changes and external load disruptions. This outer control loop also provides the current reference for the inner controller. The inner loop employs Finite Control Set Model Predictive Control (FCSMPC) to regulate the inverter and produce the output voltage necessary to fulfill the design objectives. The FCS-MPC cost function is formulated as a multi-objective optimization problem, for which the VIKOR technique is applied to determine the best compromise among competing objectives. Finally, the profiles of tracking, load disturbance, and robustness are validated in a simulation case study.