Active front end adjustable speed drives under grid voltage sags: effects and dynamical performance evaluation

In this paper an evaluation of voltage sags effects on active front end adjustable speed drives (ASD´s) performance has been carried out. The operation of such devices is affected by several disturbances that can occur on the electrical grid. According to a number of surveys on power quality, voltage sags represent the main cause of disturbances which effects are even more evident than the ones related to harmonics. Therefore, the behavior and the dynamical performances of field-orientated and direct torque control drives under grid symmetrical voltage sags are investigated and simulation as well as experimental results are presented. This kind of analysis provides useful advices for future work on how drive control technique can be modified and implemented in order to fulfill some important requirements above all on speed regulation and grid currents