Convergence of rotor flux estimation in field oriented control

The authors give a brief mention of direct air gap flux sensing methods mainly for historical reasons. They then go on to look at rotor flux linkage vector estimation using an open loop scheme in field co-ordinates. This method has some additional advantages if a field oriented controller is to be designed. The attention of the work is focused on the expected time constant of the estimation error. Finally, the study is completed by pointing out the advantages that the use of feedback in the estimation algorithm may bring in terms of the error dynamics. The results have been tested by simulation of a typical traction induction motor