Improvement of Adjustable Speed Drives (ASD's) Performance During Sag Conditions Using Ultracapacitors

Input voltage unbalance and sag conditions because of the power system line faults may lead to mal-operation of adjustable-speed drive (ASD's). In this paper, the effect of balanced and unbalanced sags on the performance of ASD's has been discussed. The improved performance of ASD's with ultracapacitors is demonstrated using MATLAB simulation.