Grid-Forming and -Following Model Predictive Control for Converters With an LCL Filter

This article presents an indirect model predictive control (MPC) scheme for grid-connected converters with an LCL filter. The proposed control system can operate in both grid-forming and grid-following modes as well as seamlessly transition between the two modes. Moreover, it is equipped with a current-limiting mechanism, implemented with a reference limiter and soft constraints in the MPC optimization problem, which ensures converter protection against overcurrents. The presented experimental results validate the performance of the proposed control system during nominal operation and under grid faults. Finally, comparisons with conventional control systems are also provided to demonstrate the superior performance of the proposed MPC strategy.