Research on topology and PWM control method of a novel cascaded multilevel inverter

Multilevel inverters have been used widely because of their high power capability, lower output harmonics and lower commutation losses and so on. Their main disadvantage is their complexity, requiring a great number of power devices and complex control method. In this paper, a new topology is proposed based on H-bridge cascaded inverter. The new topology produces a significant reduction in the number of power devices and simply topology structure using a bidirectional auxiliary switch. A new step pulse PWM method is proposed for the new topology using selective harmonic elimination pulse-width modulation (SHE-PWM) to eliminate lower order harmonics. Lastly, an experimental 9-level voltage-source inverter system is built to verify the topology and PWM control method.