Design and Simulation of Seven Level Cascaded H Bridge Inverter for Medium Power Applications

In the recent years, multilevel inverters (MLI) are highly being used for medium power and high-power applications because of several merits such as low voltage stress on the power switches, low electromagnetic interferences, low dv/dt ratio to supply lower harmonic contents in the output voltage and current. Multilevel inverters have become more popular in electric high-power application with the promise of very low disturbances and the possibility to function at lower switching frequencies than ordinary two-level inverters. It is also more efficient since the inverter has a component which operates the switching power devices at line frequency. So that there is no need for all switches to work in high frequency it leads to simpler and more reliable control of the inverter. The seven-level inverter with reduced number of switches with PWM (Pulse Width Modulation) switching is simulated. It is observed that the pulse generation using PWM switching leads to further reduction of THD. Simulations of the proposed system have been carried out in MATLAB/SIMULINK environment to show its effectiveness of Seven Level Inverter Topology for power quality issues.