Advanced torque control of induction motors fed by a floating capacitor multilevel VSI actuator

This paper deals with the direct torque control of high voltage/high power induction motors fed by floating capacitor multilevel VSI actuators. The active control strategy for balancing the capacitor voltages is presented highlighting an optimal pattern. The efficiency of this approach is compared to the well-known passive method and it is illustrated by simulation. In the next section, a controlled cycle based algorithm is proposed as an attractive solution for high performance torque control, satisfying the constant switching frequency required by IGBT. Associated simulation results show the good behaviour of this algorithm.