Design of single-phase seven-level inverter with reduced number of switching devices for PV applications

摘要

Multilevel inverters (MLI) play an important role in medium / high voltage and high power applications due to its capability to convert DC input voltage to AC output voltage with reduced total harmonics distortion (THD) and low electromagnetic interference (EMI). A new topology for single-phase seven-level pulse width modulated (PWM) inverter is presented with reduced number of switching devices compared with conventional MLIs, hence the inverter cost and circuit complexity are reduced. The seven-level inverter is composed of three identical and separate DC voltage sources and eight power switches. An LC Filter is used to eliminate the output voltage harmonics. A conventional Proportional Integral (PI) controller is used to control the output load voltage. The effectiveness of the proposed inverter is confirmed by MATLAB/SIMULINK; while load voltage regulation is experimentally (Real time simulation) validated using the Dspace-1103.