Multi-level inverter for Induction Motor Drive

In this paper space vector modulation and multi level carrier based PWM for the 4-level inverter fed induction motor drive are presented. Four-level inversion can be achieved by connecting three two-level inverters in cascade. Three isolated power supplies with DC link voltages are required for the proposed circuit topology. The voltages constitute one third of that of a conventional 2-level inverter topology. This scheme is capable of producing 512 voltage space phasor combinations distributed over 37 space phasor locations. The proposed four-level inverter configuration requires lesser number of switching devices as compared to the conventional four-level inverter scheme. Similarly, lesser-isolated power supplies are required when compared to the cascaded H-bridge configuration. This inverter scheme does not experience neutral-point fluctuations.