Robust H∞ output feedback control design applied to Uninterruptible Power Supplies

This paper deals with a robust H_∞ output feedback control strategy for a single phase Uninterruptible Power Supply (UPS). Design procedure of the control scheme is discussed. Indeed, the load is supposed unknown and the load current is considered as an external disturbance. By introducing a new error weighting filter, the proposed strategy offers good performances for both linear and nonlinear loads with low total harmonic distortions (THD), excellent voltage regulation and insensitivity to load variation. A comparison of the simulation results between the proposed strategy and a multiple feedback loop approach is presented to verify the effectiveness of our design. The results demonstrate that the proposed strategy has a significant improvement. They are proved by experiment.