Modulation in VSI for immediate flux control (IFC) with reduced flux error

The paper introduces an improved modulation method for immediate flux control (IFC) of VSI-fed induction motor drive. The new modulation approach combines complementary durations of two optimal voltage vectors within the sampling interval. In comparison with previously published modulated IFC, the new method improves the stator flux accuracy, while the commutation frequency is slightly increased. Nevertheless, the commutation frequency is lower than in SVM. The use of the proposed method is not limited only to IFC, but it can be also applied in various applications of voltage-source inverters (VSI). However, an important drawback appears, since the dead-time insertion between non-subsequent active voltage vectors requires significant modifications in established control of inverter