A New Grid connected Doubly Grounded PV Micro-inverter with Power Decoupling Capability

This paper presents a novel single stage five switch doubly grounded Photovoltaic (PV) micro-inverter topology with in-built power decoupling mechanism. The mismatch between instantaneous power at PV terminal and ac grid is buffered by an intermediate capacitor thus reducing the size of PV terminal capacitor for Maximum Power Point (MPP) operation. The Ground Leakage Current (GLC) issue of single phase PV system is eliminated by connecting the negative rail of PV terminal to grid. The operation of conventional two stage cascaded boost converter-buck inverter operation is mimicked by a single stage bipolar hybrid DC-DC converter which uses lesser switch count and unique control strategy to obtain positive and negative output voltage. The detailed operating principle of the inverter is explained with the help of equivalent circuit diagrams. Simulation results are provided to validate power decoupling control capability of the inverter.