Improved performance of sensorless induction motor using reactive power

This paper investigates a high-performance strategy in a sensorless induction motor using reactive power. The sensorless algorithm for a motor drive is based on the mathematical model including electrical variables such as motor current and voltage. Therefore, the accuracy of such variables largely affects the performance of the sensorless induction motor drive. However, the output voltage of the SVPWM-VSI(space vector pulse width modulation of voltage source inverter) supplying a motor is error-prone in the motor´s low speed range because it has a poor resolution in a low output voltage command. In this paper, a variation of the DC link voltage is proposed as a high-performance strategy overcoming the above problem. The variable DC link voltage leads to an improved resolution of the inverter output voltage, especially in the motor´s low speed range. The proposed strategy is verified through simulation and experimentation.