Three-level inverter scheme with reduced power device count for an induction motor drive with common-mode voltage elimination

A three-level inverter scheme with common-mode voltage elimination and reduced power device count for dual inverter-fed open-end winding induction motor is proposed. The open-end winding induction motor is fed by two three-level inverters, formed by cascading two two-level inverters, from both sides. These two three-level inverters share the top inverter, thereby reducing the power device count. The switching states with zero common-mode voltage variation are selected for pulse-width modulated switching so that there is no alternating common-mode voltage in the pole voltages and phase voltages. Only two DC links, with half the ratings of a conventional three-level neutral point clamped inverter, are used for the proposed scheme.