Development of multi-carrier PWM technique for multilevel inverters

Multilevel voltage source inverters are emerging as a new breed of power converter options for high-power applications. Various topologies and modulation strategies of multilevel inverters have been proposed. In this paper, the different multi-carrier PWM techniques are investigated and several interesting characteristics of them are revealed. A new method of multi-carrier PWM strategies is also proposed and compared with different conventional multi-carrier PWM techniques. Reduction of total harmonics distortion (THD) and improvement of the harmonic spectrum of inverter output voltage are some advantages of the proposed control method. The simulation results based on PSCAD/EMTDC software are presented to validate the capabilities of the proposed modulation method.