Design and implementation of an adjustable speed drive for motion control applications

In this article a hardware topology meant to compare the velocity performance of both an induction motor and a permanent magnet (PM) AC three-phase motor is presented. A variable reference is tracked by the sensorless vector-controlled adjustable speed drive (ASD) that permits, by means of the same type of control, performing the speed control loop of the two motors. The algorithms are programmed on a digital signal processor (DSP) in order to ensure efficient use of energy in the transistor bridge and proper tracking of the reference at low and high speeds. Regarding the torque performance, a laboratory test bed based on a torquemeter and two motors is constructed. The hardware implementation includes the power and the digital stages. A serial communication between the PC and the ASD is accomplished to put into operation in the user front-end because a high speed sample frequency is required for the analysis software that runs in the PC. This interface is used not only as comparing the speed response of the motors signals but also as looking the power quality analysis of each motor measurements based on software. Results are presented to demonstrate the effectiveness of the sensorless scheme