A robust indirect vector control for the rotor time constant variation of induction machines

This paper presents the on-line tuning algorithm of the rotor time constant (Tr). If the value of the Tr is set incorrectly, the indirect field oriented control (IFOC) scheme exhibits the deteriorated performance due to the detuned slip command. The effects of the Tr are caused by the slip calculator where Tr must be known to align rotor flux axis. Using the two torque angles (stationary torque angle, rotating torque angle), the variation of the Tr is identified, and the Tr of the controller is tuned to the proper value of the machine. As a result, the dynamics of the IFOC system is much improved with the proposed algorithm. For the purpose of the validity of this proposed algorithm, the computer simulations and the experiments have been performed and the explanation of the results presented