Implementation of Self Balancing Space Vector Switching Modulator for Three-Level Inverter

Abstract

This paper describes on how to formulate a self-balancing space vector modulator for the three-level neutral point clamp topology typically used for high power induction motor drives. Dependence of the DC link capacitor voltage deviation on DC-link current and inverter switching states is established for proposed three-level inverter. Pulse pattern rearrangements for space vector PWM (SVPWM) using degree of freedom available in choice of redundant space vectors, sequencing of vectors, and splitting of duty cycles of vector are best exploited. Self neutral-point voltage deviation control in feed forward is proposed in this paper. The effectiveness of proposed scheme is verified by experimental results. The modulator was successfully implemented using DSP-TMS320F2811 with a 45-kW (60 HP) motor drive. Lab test results are given for effectiveness of the modulator.