This study deals with direct torque control (DTC) of induction motor drives when a multilevel inverter is involved. The proposed control technique is finalised to reduce the amplitude of torque oscillations and to improve the motor dynamic response regardless of operating speed conditions while assuring a satisfactory input current distortion. This is achieved by using a special look-up-table built with a novel approach. The control itself is based on the application in each sampling interval of one or two voltage vectors suitably selected, in order to ensure low electromagnetic torque ripple in steady-state operations and fast dynamic behaviour in transient operations. In the algorithm, the converter voltage vectors selection is carried out by using a novel look-up table whose entry points are computed by means of a specialised relation, starting from the outputs of multilevel hysteresis controllers. The suggested method, suitable for a generic multilevel inverter, is detailed for a neutral point clamped three-level inverter. The proposed algorithm is validated by several numeric a lr e s u l t s ,a n dc o m p a r e dw i t haD T Ca l gorithm based on a traditional threespeed range look-up tables. Finally, some experimental results, obtained with a scale laboratory setup, are shown, discussed and compared with the numerical ones.

The version presented here may differ from the published version or from the version of the record. Please see the repository URL above for details on accessing the published version and note that access may require a subscription.

The version presented here may differ from the published version or from the version of the record. Please see the repository URL above for details on accessing the published version and note that access may require a subscription.

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