A PERFORMANCE COMPARISON OF DISCRETE-TIME LEAST SQUARES-BASED ROBUST MODEL REFERENCE ADAPTIVE CONTROL APPROACHES APPLIED ON GRID-SIDE CURRENT CONTROL OF GRID-TIED POWER CONVERTERS BY LCL FILTER

In this work, two Robust Model Reference Adaptive Control (RMRAC) for grid-side current control of a static 3-wire converter with LCL filter are implemented and compared. The adaptation law used to adjust gains online is a modified Least Square (LS) algorithm. In both methods there is no need using resonant controllers to reject exogenous disturbance. Thereby, it is presented, step-by-step, how to implement both strategies, pointing out benefits and drawbacks of each technique and comparing their performance to track model reference output and robustness to deal with parametric variation of grid conditions. The performance comparison parameters considered are: THD (Total Harmonics Distortion), mean of absolute tracking error and maximum overshoot. Simulation results are presented to support the discussion.