Novel carrier functions based on CFD for fundamental fortification and improved harmonic profile for multilevel inverters

This paper carved out five novel carrier functions based on Control Freedom Degree (CFD) which is aimed at producing improved fundamental voltage with reduced THD and power loss over wide operating conditions. A pulse rotation unit using digital logic circuit is designed to rotate the proposed novel carrier PWM and fundamental switching signals to balance power loss among the H- Bridges in CHBMLI. The performance of the suggested carrier based PWM strategies are studied in Matlab/Simulink and a laboratory prototype is constituted to validate the simulated results. The study avails Xilinx Spartan 3E FPGA controller for generating PWM signals from the suggested novel carriers to drive the 7- level CHBMLI for generating 7- level output voltage.