A Symmetrical Cascaded Compact-Module Multilevel Inverter (CCM-MLI) with Pulse Width Modulation

 Abstract

A Symmetrical Cascaded Compact-Module Multilevel with PWM for Multilevel Inversion Cascaded H-bridge multilevel inverters have been widely used for power electronics systems. While high-voltage blocking across power switches is not a constraint for low voltage applications, research trend has been oriented to the design of more compact module topologies as an alternative for cascaded H-bridge. Despite the generation of more voltage levels with reduced switch count, the existing module topologies in recent literature take no account of the freewheeling current path during dead-time, and thus inducing multistep jumps in voltage levels and give rise to undesirable voltage spikes.

A Symmetrical Cascaded Compact-Module Multilevel with PWM for Multilevel Inversion Addressing this concern, this paper proposes two symmetrical compact-module topologies for cascaded multilevel inverter, where freewheeling current path during dead-time is provided for smooth transition between voltage levels to prevent voltage spikes. The proposed 7-level and 13-level compact-modules demonstrated low number of conducting switches for all voltage levels. Comprehensive analysis and comparison with the latest module topologies are conducted. To validate the operation of the proposed compact-module topologies, simulation and experimental results are presented.

keywords

Cascaded multilevel inverter, compact module, pulse width modulation, symmetrical module