Improvement of dynamic performance for the direct torque controlled induction motor system fed by a three-level inverter

Higher dv/dt and neutral point voltage floating often occur at the common three-level inverter, therefore, the modified modulate strategy is first studied for an induction motor system (IM) fed by a three-level inverter to implement direct torque control (DTC), and then the SIMULINK model is set up for the direct torque controlled induction motor system fed by the modified three-level inverter's modulate strategy. Simulation results show that the modified modulate strategy can not only overcome the shortage of neutral point voltage floating and higher dv/dt in the common three-level inverter, but also reduce the torque ripple, therefore, improve the dynamic performance of a direct torque controlled IM system markedly.