Simulation analysis of an improved cascaded multilevel inverter topology

Abstract

Cascaded multilevel inverters are widely used in various fields, from oil and gas, power supply installations, to power quality devices. While there are many advantages of the cascaded multilevel inverter such as low voltage stress for each switching device and higher power quality, the main downside for this type of inverter is relatively large number of switching device it needs in an installation. In order to reduce total harmonics distortion (THD) of the output voltage waveform, the number of output voltage level need to be increased, hence the higher number of switching devices. This subsequently increases the installation cost, inverter circuit size and power losses — in the form of heat and voltage losses in the inverter circuit. In this paper a new improved cascaded multilevel inverter topology with a minimum number of switching devices is discussed. The proposed topology needs to turn on only two switching devices at any operation time for any output voltage level configurations. The switches in the proposed topology also have low duty cycle and almost balanced cells duty cycle. The cascaded multilevel inverter topology validity is verified by the Matlab Simulink simulation of a prototype single phase 41-level inverter.