Robust predictive current control with harmonic compensators for grid-connected VSI

This work presents a control strategy for grid-connected voltage source inverters in Distributed Power Generation. The proposal combines two control loops, an internal loop based on the Robust Predictive Current Control (RPCC) and an external proportional-resonant with harmonic compensators (PR+HC) to achieve high rejection to external perturbations and improve grid current THD in steady state. The proposed design framework allows to connect or disconnect the PR+HC loop during operation, showing a soft transient response after switching between control modes, in order to get the best response of both control strategies when sequenced conveniently. Simulation results are given in order to validate the proposal, and comparisons between modes of operation in transient and steady state are provided to show the advantages of the proposed methodology.