Sensorless control of AC machines at low speed and standstill based on the "INFORM" method

The increasing use of AC machines compared to DC motors in electrical drive applications has several reasons. A very important advantage of AC machines is their simple construction. However, AC drives often need mechanical sensors (tachometers, position encoders) for field orientation. In many applications these sensors reduce robustness and increase costs of a drive considerably. The main objective of this paper is to present the "INFORM" method based on real-time inductance measurements for sensorless control of AC drives.