Comprehensive Analysis of 2DOF-PI Current Controllers for Grid Connected Inverters

This paper investigates the performance of linear current control structures based on the two-degree of freedom PI structure for grid-connected multilevel inverters. The goal is to identify which among the possible configurations provides the best performance in terms of command tracking, load disturbance rejection, and noise measurement rejection in the current feedback. Stability analysis has been addressed by including the influence of the LCL filter in the current control loop. Simulation results indicate that the IP configuration provides a favorable trade-off between robustness and dynamic performance.