This example shows the vector control of an AC drive.
H.Ouquelle and Louis-A.Dessaint (Ecole de technologie superieure, Montreal)
A single phase asynchronous machine rated 1/4 HP, 110 V, 60Hz is fed by a current-controlled PWM inverter which is built using a Universal Bridge block. The speed control loop uses a proportional-integral-derivative regulator to produce the quadrature-axis current reference iq* which controls the motor torque. The motor flux is controlled by the direct-axis current reference id*. The block DQ-AB is used to convert id* and iq* into current references ia*, and ib* for the current regulator. Current and Voltage Measurement blocks provide signals for visualization purpose.
Start the simulation. Observe on the scope the motor currents, voltage, speed, and torque during the starting. Double click on the two Manual Switch blocks to switch from the constant wref=1500 rpm and TL blocks to the Step blocks. (Reference speed wref changed from 1500 to 750 rpm at t = 2 s and load torque changed from 0 to 1 N.m at t= 1s). Restart the simulation and observe the drive response to successive changes in speed reference and load torque.