Cost effective solutions to increase the immunity of AC drives against voltage dips

This paper describes cost effective solutions to increase the immunity of standard field oriented AC drives against voltage dips. The solutions are based on the classification of dips into three types and an experimental analysis of protection mechanisms applied in commercial drives. For asymmetric diptypes, complete ride-through is obtained by selecting the correct amount of dc link capacitance. For symmetric dips however, field weakening is required to maintain torque control. The performances of field weakening techniques are analyzed with respect to voltage dips. Control of an induction machine is shown to be more difficult compared to a permanent magnet synchronous machine. The methods proposed to reduce the sensitivity of AC drives against voltage dips are verified experimentally