Multilevel inverters have gained popularity in high power, and medium voltage applications because they may be used without a transformer and with less noise and harmonic distortion. Multilevel inverters produce the stair-case voltage waveform close to the sinusoidal waveform by using a variety of DC voltage levels. The topologies of multilevel inverters (MLIs) are divided into three types: Diode Clamped, Flying Capacitor, and Cascade Multilevel Inverter (CMLI). CMLI topologies are classified into two types: symmetric and asymmetric topologies. The topologies of asymmetric cascade MLI comprise different DC sources but symmetric cascade MLI consists of equal DC sources. This paper presents a comparison between 9 symmetric MLI and 31 asymmetric MLI, and the technique of MCPWM is used to compare the two topologies. This study used two techniques from MC-PWM which are named Phase Disposition PWM, and Phase Opposition Disposition PWM. It has been discovered that the Phase Disposition PWM approach is more convenient in terms of Total Harmonic Distortion of output voltage in Asymmetric Cascade MLI, In general, an asymmetric topology at 31 levels was best than a symmetric topology at 9 levels. Using MATLAB / Simulink environment has been done to build models.

Cascaded H-bridge multilevel inverter (CMLI), Multi carrier pulse width modulation (MC-PWM) technique, and Total harmonic distortion (THD), Phase Disposition PWM(PD-PWM), Phase Opposition Disposition PWM(PODPWM), Asymmetric Cascade MLI (ACMLI).