A multilevel Voltage Source Inverter (VSI) to maximize the number of levels in output waveform

Abstract

Recently multilevel inverters are gaining popularity due to reduced voltage stress across power switches and low total harmonic distortion (THD) output voltage waveform. However, device count increases with increased voltage levels. This paper presents a novel multilevel topology which is capable of obtaining all additive and subtractive combinations of input DC levels in the output waveform. Though all such levels can be obtained using the proposed topology, the actual number of levels depends on the DC source arrangement. A comparison is made between proposed topology and the classical multilevel topologies on the basis of device count and number of levels in the output voltage waveform. A detailed study of the proposed topology is presented through the example of a nine-level inverter. Appropriate modulation scheme is also presented. The proposed concept is analyzed through simulation studies and verified experimentally.