The Active Flux Concept for Motion-Sensorless Unified AC Drives: a review

Boldea I., Agarlita S. C.

International Aegean Conference on Electrical Machines and Power Electronics / Electromotion Joint Conference, İstanbul, Turkey, 8 - 10 September 2011, pp.1-16 identifier

  • Publication Type: Conference Paper / Full Text
  • City: İstanbul
  • Country: Turkey
  • Page Numbers: pp.1-16
  • Keywords: AC motor drives, active flux, estimation, magnetic, MAGNET SYNCHRONOUS MOTOR, VECTOR CONTROL, DIRECT TORQUE, POSITION, SPEED, MODEL, SATURATION


Rotor and stator flux orientations are now standard concepts in vector and direct torque control of ac drives. The salient-pole rotor machines, where magnetic saturation plays a key role, still pose notable problems in flux, rotor position and speed estimations for motion-sensorless control, especially in the low-speed range (below 30 rpm in general), leading to numerous dedicated state observers. This paper review introduces a rather novel (or generalization) concept active flux or torque-producing flux and its utilization in all ac drives by employing a unified state observer for motion-sensorless control in a wide speed range. The active-flux concept "turns all salient-pole traveling field machines into nonsalient-pole ones". The active-flux vector is aligned to the rotor axis for all synchronous machines and to the rotor-flux vector axis for induction machines. This way, the rotor position and speed observer seems more amenable to a wide speed range, with smaller dynamic errors. This observer, based on the active-flux concept, is pretty much the same for all ac drives. Example of implementation, for IPMSMs, RSM, dc-excited SM with experiments are reviewed to illustrate de concept.