A new couple inductor based 9-level inverter with reduced number of switches for standalone /grid connected solar PV systems

In this paper, a single phase coupled inductor based 9 level diode clamped inverter is proposed for stand alone and grid connected solar PV applications. The proposed inverter is capable of generating 9 voltage levels with one DC source. It has a lower part count compared to the conventional nine level inverter topologies. The presence of the high frequency coupled inductor in the output power path provides natural protection against shoot through problems. Hence dead band requirements in the power switches are eliminated. Because of lesser components in the power circuit, the system size is considerably reduced. The proposed inverter topology contains less number of input capacitors and voltage stress on the devices is less. Due to the presence of fewer components, the overall efficiency of the system is high. Due to 9 levels in the inverter output voltage, the waveforms are of high quality with a THD of only 0.27%. The proposed topology is simulated for a 1200W system and all the simulation results of this work are presented.