Implementation of LDN to MLI and RSC-MLI configurations with a simple carrier-based modulation

Abstract

The design of multilevel inverters (MLI) and reduced switch count (RSC) MLIs majorly depend on the requirements of desired output voltage levels, number of dc sources switching devices, and their ratings. With regard to these requirements ‘Level Doubling Network (LDN)’ configuration is introduced. LDN has the ability to double the output voltage levels of any MLI or RSC-MLI, preserving inverter modularity. However, the implementation of LDN to MLI or RSC-MLI is not unified and varies with switching operations. Thus, this work presents the implementation of LDN to popular MLI and RSC-MLI configurations and further presents a brief comparison on theswitch count, number of levels, and harmonic performance for both LDN and non-LDN cases. Further, a generalized carrier-based PWM scheme is presented to implement the LDN for any MLI and RSC-MLI configurations irrespective of voltage levels, dc-voltage ratios, and topological configuration. The performance of the inverter and the proposed modulation scheme are validated on MATLAB/Simulink environment.