Direct torque control of an induction motor fed by a Quasi Z-source inverter

This study presents an adapted direct torque control (DTC) of an induction motor fed by a Quasi Z-source power inverter. Indeed, the Quasi Z-source structure is introduced in the power inverter in order to boost the DC-Link voltage. For this, the boost control is mainly based on the shoot-through states of the power inverter which two power switches can be turned on at the same time. In this context, a switching table for DTC is developed to ensure an independent control of the flux and the torque of the induction motor and to boost the DC-Link voltage. Thus, the sampling time should be shared alternatively between the boost of the DC-Link voltage and the control of the electromagnetic torque. Consequently, the developed system reduces both the boost floor and the number of the used power switches. Moreover, it ensures a high-performance induction motor control. The validation results have been carried out to prove the effectiveness of the developed control.