Detection of Some Parameters of Induction Motors a Proposal and Its Verification

This paper describes a novel approach for offline stator leakage inductance estimation method that can be used for self-tuning of induction motor drives. The paper briefly describes the theory behind the approach. The proposed method is based on applying a DC voltage to the motor windings and measuring the DC current that flows in the circuit over a short interval of time. The measured variables are DC quantities and relatively noise free as compared to some other available methods. The proposed approach is tested on three industrial induction motors. It is shown that the prediction accuracy is very good. However, it is noted that some means of filtering the prediction fluctuations in the measurement is desirable. An on-line stator resistance prediction method is also introduced in the paper. This method requires very little computation effort as most of the variables requires for the calculations are already done within a sensorless vector control implementation. When this approach is tested on three industrial motors its estimation results are found to be very accurate.