Parameter estimation of an LCL filter for control of grid converters

Model-based control techniques are frequently used with grid-connected converters. This paper proposes a method for identifying model parameters of an LCL filter connected to a grid converter for control purposes. In identification, a discrete-time autoregressive moving average with exogenous input (ARMAX) model structure is used and closed-loop current control is considered. The resulting discrete-time model parameters are translated into the continuous-time physical parameters (inductance and capacitance values of the filter) by comparing the estimated discrete-time model with the analytical discrete-time model. Simulation and experimental results show that the proposed method yields good parameter estimates that are suitable for control tuning.