Exploring a Novel Topology for Asymmetrical Multilevel Inverters: A Deep Dive into 7-Level and their Expansion to 19 Levels

The inverter serves as a crucial power electronic apparatus, facilitating the conversion of DC power input into AC power output at desired frequencies and its voltage levels. Due to the non-availability of any rotating parts and the higher level of switching ability, it boasts enhanced efficiency and reliability. In contemporary times, the inverter has evolved beyond a mere device to become an integral component of the power industry. However, traditional inverters, with only two levels, yield output waves significantly distorted from the fundamental sine wave of the same period and frequency, thus introducing harmful harmonics into the circuit. These harmonics not only diminish the overall system efficiency but also accelerate system aging due to heating effects, posing a risk of faulty operation. The presence of harmonics not only distorts the load but also impacts the entire power system negatively. Consequently, the concept of multilevel inverters emerged to mitigate waveform distortion by increasing the levels of inverter. It can be seen that as the number of voltage levels increases, the output voltage approaches sinusoidal in nature, thereby reducing harmonic content. This paper introduces a novel asymmetrical MLI topology for a 7-Level Inverter, elaborating on its operation and extending the topology to a 19-Level Inverter.