State-space black-box model identification of a voltage-source converter with LCL filter

The paper proposes a multivariable identification method to identify the discrete state-space model of a grid-connected voltage-source converter and LCL filter. The method is based in one of the so-called subspace identification methods: the N4SID method. That kind of methods are based on the QR and the Singular Values decompositions and works with black-box state-space model structures, which mean particularly flexibility in the choice of the model representation. The so obtained discrete state-space model of the converter could be used to design directly the control of the system using advanced control techniques as robust control, optimal control, etc.