Effects of Inverter Faults and Line Disturbances on Sensorless Position Estimation

Fault tolerance of adjustable speed drives and ride-through capabilities against voltage sags, swells and under voltages have been widely addressed in the past. However, the research activities in these fields have been always focused only on conventional sensored motor drives. In this paper, a detailed analysis regarding the robustness of sensorless controlled electrical drives to inverter faults and line disturbances is presented. In particular, two categories of sensorless control strategies are tested under some unusual working conditions: model-based and HF injection based techniques. Experimental results performed on an IPMSM drive shows and compares the limitations of the analyzed sensorless implementations in presence of fault.