A High-Performance Strategy for Sensorless Induction Motor Drive Using Variable Link Voltage

Most sensorless algorithms for a motor drive are based on a mathematical model including electrical variables such as motor current and voltage. Therefore, the accuracy of such variables largely influences the performance of the sensorless motor drive. However, the output voltage of the space vector pulsewidth modulation of the 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. This letter proposes a variation of the dc-link voltage as a high-performance strategy for overcoming the above problem in a sensorless induction motor drive. The proposed strategy is verified through simulation and experimentation