DSP based current regulated PWM inverter-fed induction motor drive without speed sensor

This paper presents a simple sensorless voltage-controlled current-regulated PWM inverter-fed induction motor drive implemented on a floating point DSP from analog devices (ADSP 21020). In contrast to the system presented earlier, where a current regulator working in stator oriented coordinates (ac components) was applied, the proposed scheme uses a current regulator working in synchronous rotated coordinates (DC components). Moreover, a novel slip estimator based on the knowledge of internal voltage components of the modulator and motor parameters is developed. The estimated slip value is used for compensation of load torque changes. Hence, the system can operate without speed and voltage sensors. Experimental results which illustrate the performance of the proposed system are presented and it is concluded that the system performance is significantly improved compared with a standard industrial drive.