Three-level inverter-fed synchronous motor drive system

In this paper a simple mathematical model of the three-level inverter-fed synchronous motor drive system is presented. The three-level inverter would allow high voltage and high power sharing among its switching devices. It also reduces the devices switching frequency. Speed control of the presented drive system may be achieved using numerous numbers of modulation schemes. Two modulation schemes are presented, the single pulse-width-modulation (SPWM), and the multiple pulse-width-modulation (MPWM). Under the aspect of harmonic current reduction, the MPWM scheme has a much lower harmonic content than SPWM scheme. The developed model is adaptable to inverters of any higher number of voltage levels. A laboratory prototype of the presented drive system is tested. Experimental results proved a very promising drive system