Analysis of cascaded H bridge multilevel inverters with photovoltaic arrays

Now-a-days, photovoltaic (PV) power systems are getting more and more widespread with the increase in the energy demand and the concern for the environmental pollution around the world. Multilevel inverters (MLI) have gained much attention in the area of energy distribution and control due to its advantages in high power applications with low harmonics. Out of different structures of MLIs, Cascaded H Bridge (CHB) MLI is more suitable converter for PV applications since each PV panel can act as a separate DC source for each CHB module. The performance of symmetrical and asymmetrical single phase CHB multi level inverter with respect to harmonics content, number of switches and voltage stress across the switch with photovoltaic cell as its input source is simulated by using MATLAB/Simulink. A detailed harmonic analysis is done on the PV fed CHB-MLI by considering up to 23^rd harmonics for 7 levels to 15 levels operation. Finally, the effect of change in irradiation and temperature on the performance parameters is also studied.