A simplified space -vector PWM for three level inverters applied to passive and motor load

Abstract

Advances in power electronics technology allowed the wide investigation of multilevel converters that provide high safety voltages with less harmonic components compared to the two-level structures .Because of prominent advantages like more utilization of input voltage, flexibility in switching the legs of three phase inverters and easy method of improving spectral performance and easy digital implantation, space vector modulation (SVPWM) has become the most popular technique for three phase voltage source converters for the control of AC/DC drives and flexible AC transmission application(FACT) controllers. But implementation of space vector modulation (SVPWM) for more than two levels is difficult because for them no. of switching states is very high. In this paper simplified method is proposed in which timing calculation is required for only one sector and therefore calculations are tremendously reduced and the same could be applied to different types of multilevel inverters like flying capacitor and cascaded. To check the validity of the scheme, simulations are done for passive (R-L) load and motor load. Open loop V/f speed control method of induction motor is also done to enhance the validity of the scheme.