Finite-Set Model Predictive Control Based on Optimal Switching Sequence Strategy for Grid-Forming Inverter

Currently, model predictive control-based virtual synchronous grid-forming control strategies suffer from high harmonic content and low prediction accuracy. This paper proposes a virtual synchronous grid-forming control strategy based on multi-step finite-set model predictive control. The strategy employs virtual synchronous control in the inner power control loop and an error-compensated single-vector multi-step model predictive control algorithm in the outer loop to improve control accuracy and reduce harmonic content. Additionally, the optimized voltage vector based on the optimal switching sequence further reduces current ripple and achieves constant switching frequency. Compared to conventional predictive control methods, the proposed method features smaller control errors and lower harmonic content.