Analog control scheme for Cascaded Multilevel Inverters based on multiple carrier PWM technique

Abstract

The paper presents an analog control technique applied to the Cascaded Multilevel Inverter in order to ensure an efficient voltage utilization and better harmonic spectrum. The method presented shows a Multiple Carrier Phase Opposition Disposition PWM topology to control the cascaded multilevel inverter that is implemented with multiple DC sources, which can also be obtained using a single DC source and transformers to get 2n+1 levels. The hardware implementation has been carried out using operational amplifiers on a scaled down prototype to prove the effectiveness of the proposed topology. This topology of firing can be implemented on the inverters used for the renewable energy sources where it can considerably reduce the switching losses, thereby improving the conversion efficiency and also brings down the Total harmonic distortions.