Novel Asymmetric Hybrid 15 Level Inverter with Reduced Number of Switches Using Different PWM Techniques – Part II (Hardware Studies)

Abstract: This paper presents a new asymmetric cascaded H-bridge Multi Level Inverter (MLI) with less number of power devices for industries and renewable energy applications. Cascaded MLI are more popular in electric utilities and industrial drives. MLI reduces Total Harmonic Distortion (THD) present in the output voltage. MLI performance is very good on the higher value of voltage apply to the drive. The cascaded H-bridge inverters are classified based on the input supply voltage from the unequal sources like symmetric and asymmetric inverter. The proposed topology consists of one H-bridge (with 4 switches) and full bridge unit (with 3 switches) for 15 level output voltage. In this paper THD is reduced to 3.23% by using SPWM technique. THD analysis is calculated by FFT spectrum of output waveforms using MATLAB/SIMULINK. The proposed topology is verified through the prototype hardware of single phase 15 level hybrid asymmetric inverter using FPGA based Xilinx SPARTAN 3E processor. These processors provide proper gating signals for switches using SPWM application.

Keywords: Asymmetric Multilevel inverter (AMLI), Total Harmonic Distortion (THD), PWM methods.