Estimation of the rotor resistance in induction motor by application of the spiral vector theory associate to extended Kalman filter

For guaranteed good performances in transient and steady state in vector control of induction motor, it´s necessary to conceive regulation of parameters variations, in particular rotor resistance. To solve this problem, innumerable works are devoted to rotor resistance, but they use Park´s model of the induction motor for estimating this resistance. However this model use a hefty geometric transformation for calculation. In this paper the authors propose for the first time the application of an extended Kalman filter to rotor resistance estimation in an induction motor by taking account of spiral vector theory. The model obtained by the spiral vector theory permits to obtain a reduction in model order and permits also to use only two sensors (one for current and one for voltage) compared to Park´s model where it´s necessary to use four sensors (two for current and two for voltage).