Design of 7-level cascade asymmetric multilevel inverter for renewable energy applications using FPGA

The increasing focus on renewable energy has driven the need for efficient 
and reliable power converters. Multilevel inverters offer low harmonic 
distortion and high-quality output but often suffer from design complexity 
and excessive component count. This study presents the design and 
implementation of a 7-level cascaded asymmetric multilevel inverter 
optimized for renewable energy applications. The proposed topology utilizes 
a cascade structure with asymmetric DC voltage sources to generate seven 
voltage levels, providing a practical balance between performance and 
simplicity. The design was first validated through MATLAB/Simulink 
software to analyze circuit operation and evaluate the total harmonic 
distortion (THD) performance. Experimental evaluation was then conducted 
using a hardware prototype to verify simulation results. Without a filter, the 
THD from the simulation was 21.31%, while the experimental setup 
recorded a slightly higher value of 21.61%, indicating a marginal difference 
of 0.21%. With a filter, the simulation achieved a THD of 3.81%, whereas 
the experimental setup outperformed with a THD of 1.5%, showing a 
notable reduction of 2.31%. These findings confirm the proposed inverter’s 
capability to deliver superior power quality and operational efficiency. 
The combination of simulation and experimental validation demonstrates the 
practicality and reliability of the 7-level cascade asymmetric multilevel 
inverter for renewable energy applications.