Contribution to model LCL filters connected to the grid with uncertain parameters

This work provides a simple and effective state space discrete-time model for LCL filters connected to the grid with uncertain inductance. This model is suitable for the design of digital robust controllers for this application. The proposed description is given by the combination of matrices obtained for the minimum and maximum values of the grid inductance, and is capable to provide small errors with respect to a more accurate but numerically complex model, as proven by the results in the paper.