Comparative analysis for Cascaded H-Bridge Multilevel Inverter

Multi - level inverter (MLI) circuits are frequently used in power production, power quality devices, and energy transmission, among other applications. Conventional MLI have certain limitations, such as a larger percentage Total Harmonic distortion (THD) % and a lower voltage magnitude. In this work, various topologies for (five-level) cascaded multilevel inverter are designed and implemented. The first topology is of Conventional Cascaded Multilevel Inverter design and the second topology, on the other hand, Cascaded Multilevel Inverter with a 6-switch count. H-bridges are connected in series to produce the required number level for the voltage output. These topologies are designed with the different PWM techniques i.e., Multicarrier SPWM and SVPWM and are compared for better THD value in the output voltage side with the increased no levels, it becomes more complex to apply the space vector PWM technique. Thus, an easier and simpler methodology (which is proposed in several literatures) have been applied. Total four topologies (also with and without filter) are designed and simulated in MATLAB simulation software and compared as well. Also, to further reduce the harmonics a low pass LC filter is designed and applied to the inverter circuit. The stated article presents a comparison within each topology based on its input DC voltage, percentage THD, Vrms, number of switches, as well as H-bridge prerequisite, among other factors. SIMULINK/MATLAB is used to determine how well the entire system is functioning.