A New Switching Technique for Direct Torque Control of Induction Motor using Four-Switch Three-Phase Inverter

This paper presents a new switching technique for direct torque control of induction motor using four-switch three phase inverter (DTC-FSTPI-IM) for low power applications. The modified switching table in this method is based on the principle of similarity between FSTPI and SSTPI (six-switch three phase inverter), where the alphabeta plan is divided into 6 sectors and the formation of the voltage space vector is done in the same way as for SSTPI by using effective (mean) vectors. This approach allows using the well-knowing established switching table of SSTPI for FSTPI, in order to reduce torque ripples in comparison with the conventional DTC method for FSTPI. The validity of new proposed technique is verified by simulation results using Matlab/Simulink and also experimentally by using DSpace 1104 Card.