Simulation and Prototype Implementation of Hybrid H-bridge MLI with Minimum Switches

Abstract

As the demand for electrical energy increases continuously, we cannot rely on the existing conventional source for continuous power supply, as they are diminishing fast. The renewable energy sources are the best alternative for this energy crisis. We have different types of renewable energy sources and choice of source depends on location and load requirement. The most prominent source is the solar energy because of its own advantages. The nature of supply from this source is DC and it is to be converted into AC for supply to consumers. However, inverters are used for this conversion but produces harmonics. The Multilevel inverters are the alternate choice over conventional inverters due to the advantages of Low dv/dt and lower switching losses. Out of various multilevel inverters, cascaded H bridge (CHB) MLI topology is a well known solution for reducing the harmonics, which needs more number of switches and isolation power supplies which further increases the cost. This paper describes a proposed hybrid H-bridge topology with reduced switches. The proposed topology is implemented in Matlab/Simulink and results for 5, 7, 9 and 11 level are analyzed with their THD in output voltage. Hardware model for 5-level inverter is developed using 8051 micro-controller and results are presented.