Realization of Active Neutral Point Mulitilevel Inverter Using SPWM Technique

Abstract

Because of some technical and some historical reasons AC power is more popular than DC. Inverter has become very important power electronics converter for having adjustable AC power output which is need of majority of industrial equipments. For better quality of output various modulation techniques are being implemented. As these techniques require high frequency operation which results in higher switching losses multilevel inverter are preferred for medium and high power applications. Multilevel inverters can give better quality output at low modulating frequency because of their multi step output. In this paper popular Sine wave Pulse Width Modulation (SPWM) has been implemented for Active Neutral Point Clamp (ANPC) multilevel inverter which has some better features with respect to standard diode clamp, flying capacitor or cascaded H-bridge topologies. This kind of multilevel inverter is a hybrid type of multilevel inverter in which a 3 level flying capacitor clamp multilevel inverter is cascaded to a 3 level diode clamp multilevel inverter. As low frequency Selective Harmonic Elimination technique has limitation of computational complexity for elimination of more than two harmonics simultaneously SPWM has been implemented to achieve a good quality output. Advance Risk Machine (ARM) controller has been used for generating control signals. Complete scheme has been discussed in this paper. Prototype of 5 level ANPC has been fabricated for experimentation and results are presented from the experiments.