Decoupled random modulation technique for an open-end winding induction motor based 3-level inverter

This paper presents a random pulse width modulation (RPWM) technique for 3-level inverter based on open-end winding induction motor. A 3-level inverter can be realized by feeding an induction motor in open-end winding configuration with two 2-level inverters from both sides. A decoupled random PWM strategy for an open-end winding induction motor drive is proposed in this paper, in which, the switching signals for the individual inverters are derived separately. In the proposed scheme, the instantaneous switching states for the inverters are independently generated by comparing the decoupled reference voltage of the individual inverters with a random carrier wave. The proposed scheme is implemented for 2hp induction motor drive and experimental results are presented. Experimental results showing the comparison of the performance of the proposed scheme with that of the sine-triangle PWM is also presented.