Comparing of switching frequency on vector controlled asynchronous motor

Nowadays, asynchronous motors have wide range use in many industrial applications. Field oriented control (FOC) and direct torque control (DTC) are commonly used methods in high performance vector control for asynchronous motors. Therefore, it is very important to identify clearly advantages and disadvantages of both systems in the selection of appropriate control methods for many industrial applications. This paper aims to present a new and different perspective regarding the comparison of the switching behaviours on the FOC and the DTC drivers. For this purpose, the experimental studies have been carried out to compare the inverter switching frequencies and torque responses of the asynchronous motor in the FOC and the DTC systems under different working conditions. The dSPACE 1103 controller board was programmed with Matlab/Simulink software. As expected, the experimental studies showed that the FOC controlled motors has a lessened torque ripple. On the other hand, the FOC controlled motor switching frequency has about 65-75% more than the DTC controlled under both loaded and unloaded working conditions.