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This paper suggests a current injection-based estimator to accurately identify standstill induction motor (IM) parameters necessary for the vector control. A mathematical model that faithfully represents the general deep bar effect is introduced. Then, two exciting signals with a different frequency are sequentially injected to track the parameters based on the frequency function of the rotor bar. Little knowledge of the unknown motor allows the proposed methodology to employ a closed-loop control of an injected current, rather than open-loop voltage injection approaches commonly used in sensorless control schemes. Subsequently, this control scheme proactively prevents electrical accidents resulting from an inadequate open-loop voltage injection. We develop a specialized offline commissioning test to compensate the phase delay resulting from the drive, which significantly affects the estimation precision. The effectiveness of the identification technique is validated by means of experiments performed on the three different IMs. The developed algorithm is scheduled to be fully applied to the IM drive system in rolling mill plants of Pohang Steel Company (POSCO) by 2009. Keywords -Closed-loop control of an injected current, currentinjection-based estimator, frequency function of the rotor bar, standstill induction motor (IM) parameters, vector control.

We propose a current injection-based estimator to identify accurately standstill induction motor (IM) parameters necessary for vector control. A mathematical model that faithfully represents the general deep bar effect is introduced. Then, two exciting signals with a different frequency are sequentially injected to track the parameters based on the frequency function of the rotor bar. The proposed methodology employs closed-loop control of an injected current due to little knowledge of the unknown motor, rather than the open-loop voltage injection approaches commonly used in sensorless control schemes. Subsequently, this control scheme proactively prevents electrical accidents resulting from inadequate open-loop voltage injection. Our developed specialized offline commissioning test compensates for the phase delay resulting from the drive, which significantly affects estimation precision. The effectiveness of the identification technique is validated by means of experiments performed on three different IMs. Index Terms-Closed-loop control of an injected current, frequency function of the rotor bar, standstill induction motor (IM) parameter identification, vector control.

This paper presents a minimization technique of the position detection error resulting from the zero current clamping (ZCC) effect for pulsating high-frequency (HF) signal injectionbased sensorless drives. An analytical model is derived to obtain an accurate map of the ZCC effect of the PWM inverter. This model is universally agreed upon and subsequently incorporated into the development of a specialized offline commissioning test to identify the detailed model parameters. The proposed algorithm combines an offline commissioning approach and an online feedforward compensation in the stationary reference frame to achieve the minimal position error. Experiments illustrate the effectiveness of the proposed method in suppressing the position error caused by the ZCC disturbance.