A Sensorless Vector Control of Induction Machines Based on Hybrid Model

Direct field orientation of induction machines based on voltage model has an unsatisfying performance at low speed range. On the contrary, direct field orientation based on current model doesn´t work well at high speed range. A based on voltage-current hybrid model rotor flux observer can figure out the above problems. The flux observer can run in the current model at low speed and switch to voltage model at high speed and smooth between them. Depend on flux observer, a simple open-loop speed estimator used in the vector control scheme. The speed estimator can filter out amplifying noise generated by the pure differentiator and satisfy dynamic and steady state need. The simulation and experimental results shows that the sensorless vector control based on hybrid model can satisfy steady performance at wide speed range.