A Single Phase Single Stage SEPIC-ĆUK Based Non-Isolated High Gain and Efficient Micro-Inverter

A new single phase, single stage, non-isolated, micro-inverter capable of evacuating power from individual solar PV modules in a solar power station, and feeding it to the single phase Indian grid which is rated at 220-230 volts, is proposed in this paper. The operation of the converter in coupled inductor based SEPIC mode during positive half cycle, and in coupled inductor based ĆUK mode during negative half cycle ensures that high gain is achieved while involving minimum number of high frequency switches. Energy stored in the equivalent leakage inductance is utilized at the output stage, which enhances the overall efficiency of the system. There is no path for the ground leakage current to flow. Further, the possibility of shoot-through faults are also non existent in this configuration. The principle of operation of the converter is explained in detail. Thorough analytical study of the converter topology has been carried out, and subsequently small signal models of the converter for both the half cycles are derived. Based on the aforesaid small signal models, a suitable current controller for the converter has been developed. The viability of the proposed converter is confirmed by performing detailed simulation studies.