A new rotor time constant estimation method for indirect vector controlled induction motor drive

Indirect vector controlled induction motor drives exhibit excellent behaviour even in the low speed region. Thus these motors can be advantageously employed as actuators in several high-performance motor applications. Since the indirect vector control scheme is sensitive to changes in the rotor time constant, the implementation of an estimation mechanism is essential for the success of such a control system. In this paper, a new rotor time constant estimation method for an indirect vector-controlled induction motor drive is described. Its features are simple and cheap implementation and independence of motor parameters which drift with temperature. It does not require any additional transducers or any injected test signals to the stator. The estimation is performed while the loaded motor operates under steady-state conditions. Simulation results are presented which verify the proposed estimation scheme.