Adaptability of 9-switch inverter configurations for multiphase induction motors with phase reconfiguring techniques

Abstract

The 9 switch inverter (9SI) configuration is capable to control the power for two independent 3-phase loads simultaneously. However, this 9SI has the limitation on modulation index (M.I) since each inverter leg is controlled with 2 reference waves and one carrier wave. This lower M.I result in higher magnitude requirement of DC-link voltage. In addition to this, the load gets 2 level voltage only. For addressing these issues, in this paper, the 9 switch inverter (9SI) configurations for multiphase (>3) Induction motor (MIM) drives is explored. The 9SI configurations with split winding will generate the 3-level voltage across the effective phase winding of 6-phase and 9-phase IM drives. The phase reconfiguring techniques for enhancing the modulation index of proposed 9SI based multilevel inverter (MLI) fed 6-phase as well as 9-phase machines is proposed, where the phase difference between two identical voltage profile coils (IVPC) excited with same Inverter leg is minimized. The possible phase reconfiguring concepts for both symmetrical and asymmetrical configurations of the 6-phase and 9-phase machines are presented. The generalized adaptability and analysis of the proposed 9SI configurations with phase reconfiguring techniques for a machine with any number of phases is presented. The carrier based space vector pulse width modulation is implemented for proposed 9SI based MLI configurations which enhances the M.I further by 15.4%. The 9SI based MLI fed symmetrical 9-phase IM drive is validated by using Ansys Maxwell 2D