One-step ahead model predictive controller of three-phase inverter for uninterruptible power supply applications

This paper presents a dual-loop inverter voltage control strategy for uninterruptible power supply (UPS) utilizing an one-step ahead model predictive control in the inner-loop. The proposed MPC optimizes the cost function of the error state through a simple online membership test; any numerical method is not necessary. Moreover, any off-line optimization is not required. It is shown that the proposed MPC makes the closed-loop system globally asymptotically stable in the presence of input constraints. Following the conventional dual-loop strategy, the PI controller is used in the outer-loop to regulate the output voltage. The effectiveness of the proposed MPC scheme is experimentally shown under an unexpected load changes.