Implementation of a robust optimal tracking control for a grid-connected three-phase inverter

This paper presents the application of a robust nonlinear optimal controller for regulating the active and reactive power in a grid-connected three-phase inverter, which includes an LCL filter to mitigate the total harmonic distortion. The optimal control law is derived from the Hamilton-Jacobi-Bellman equation for state-dependent coefficient factorized nonlinear systems. An integral control term is included in the optimal controller to reject unknown disturbances. The effectiveness of the proposed control law is experimentally validated on an inverter prototype.