Abstract
Standing out for their remarkable benefits, such as lower voltage stress on integrated semiconductor devices, reduction in total harmonic distortion, as well as lower electromagnetic effects, multilevel inverters (MLIs) increase their share in the field of energy supply. The multilevel inverter is an interesting research topic that realizes the generation of desired output voltage waveforms composed of small voltage steps. However, many studies have put a premium on the structure, efficiency, and output of the multilevel inverter, but there are relatively few studies on the THD and practical product applications. Consequently, in this brief perspective, some puzzles for MLIs are pointed out to explore new ideas as well as to present new questions.