Space vector modulation in three-phase three-level flying capacitor converter-fed adjustable speed drive

Abstract

This Chapter is devoted to the Space Vector Modulation (SVM) in three-phase three-level Flying Capacitor Converter (FCC) fed adjustable speed drive (ADS). First, the classical and adaptive SVM are described. The adaptive SVM provides reduction of number of switching in the whole linear range of the converter operation because minimal number of vectors is used in each modulation region. As result, switching losses in FCC are reduced in comparison to the classical SVM and thus, the converter efficiency is increased. Next, elimination of DC sources unbalance in full range of operation of the FCC is presented. The minimization of the flying capacitors voltages pulsation is obtained by the compensation of flying capacitors voltages balancing delay based on prediction of those voltages values in next modulation period. Finally, taking to account the requirements of the demanding ASD application: low speed operation without phase current distortion and the high speed operation over the linear range of the converter with reference output voltage amplitude, the additional features for both modulation techniques: The dead-time effect and semiconductor devices voltage drop compensation as well as the overmodulation algorithm are shown. © Springer International Publishing Switzerland 2014.