A review of various carrier based PWM methods for multilevel inverter

The Multilevel inverter is emerging as a new breed of power inverter option for high power applications, Especially for FACTS controllers. This can create high voltage and reduce harmonics by its own circuit topology. The power levels of the inverter are largely restricted by carrier frequency. For air cooled design the frequency is practically limited to 3 to 5 KHz for large inverters, hence to increase power level it is proposed to operate two inverters in parallel with phase shifted carrier. The equivalent carrier frequency can be doubled and the output harmonics will be reduced here in this paper simulation of various carrier based PWM methods had been explained. Results and comparison also discussed.