Random PulseWidth Modulation Technique for a 4-level Inverter

Random Pulse Width Modulation (RPWM) technique for a 4-level inverter in open-end winding induction motor configuration is proposed in this paper. Reference voltage space vector is randomly sampled and it is realized in average sense by switching its three nearest vectors. Switching frequency is randomly varied within the bounds to get randomly spaced samples. The method requires no sector identification. The reference phasor is converted into a vector lying in the basic 2-level inverter to calculate switching time vectors. The proposed scheme is implemented and experimental results are presented for a dual inverter fed 4-level open-end winding induction motor drive using DSP platform, TMS 320LF2407A.