  A rapid deployment of renewable generation has led to significant reduction
in the rotational system inertia and damping, thus making frequency control in
power systems more challenging. This paper proposes a novel control scheme
based on Model Predictive Control (MPC) for converter-interfaced generators
operating in a grid-forming mode, with the goal of exploiting their fast
response capabilities to provide fast frequency control service to the system.
The controller manipulates converter power injections to limit the frequency
nadir and rate-of-change-of-frequency after a disturbance. Both centralized and
decentralized MPC approaches are considered and compared in terms of
performance and practical implementation. Special attention is given to the
decentralized controller by generating an explicit MPC solution to enhance
computational efficiency and reduce hardware requirements. Simulation results
obtained from a high-fidelity differential-algebraic equation model of the IEEE
39-bus system demonstrate the effectiveness of the proposed control schemes.
