Abstract
In the speed sensorless control of the induction motor, the machine parameters (especially the rotor resistance R2) have a strong influence to the speed estimation. In addition, the output voltage error due to the dead time and the voltage drop of the inverter influence on the rotor flux estimation, but the simultaneous compensation of the output voltage and the stator resistance R1 is very difficult. In this paper the new algorithm of R2 estimation with utilizing only stator current is proposed. In the high frequency range, the R2 is estimated in the transient state, and in the very low frequency range, R2 is estimated in proportion to the estimated R1 when the ideal voltage source by the power op-amp is used instead of the voltage source inverter to avoid the output voltage error. In use of these algorithms, the low speed estimation was possible and the zero speed control was achieved under the 5_??_40% load condition in two motors. This paper clarified that the zero speed estimation is possible with the stator and rotor resistance estimations when the output voltage is ideal.
