A Speed Sensorless Induction Motor Control Method using Adaptive Flux Observer Improving Stability Around Zero Frequency

Authors have proposed the speed sensorless vector control method that can stabilize the speed estimator in regeneration region as well as in powering operation. However, actual experimental results showed there were problems when it is driven at unloaded or around zero frequency with heavy load. In this paper observer gains are reviewed and modified with considering the phase condition which they must satisfy. Finally, the proposed observer gain scheduling method is confirmed its effectiveness and performance with experiments.