Single-Phase Non-Isolated Inverter With Shared-Ground and Broad Input Voltage Operation

The produced voltage of photovoltaic (PV) system is largely affected by environmental variables, such as light intensity and temperature. The PV power conditioning system is required to regulate output ac voltage for broad input voltage variations. This article proposes a new single-phase nonisolated PV inverter with wide input voltage range, due to its buck-boost voltage inversion in a single-stage. The most standout feature of the proposed inverter is its simple and compact construction, as it can be fabricated by adding second-order input and output <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i>filters to an integrated three-leg inverter module. A small value film capacitor is added across inverter module, providing energy storage and also acting as natural lossless snubber for switching devices. It contributes a shared-ground point between PV panel and grid-neutral, eliminating the common-mode voltage variations (at high-frequency) by clamping the voltage between grid and PV panel. Therefore, it can successfully eliminate the flow of leakage current by parasitic capacitors of transformerless PV inverter systems. The proposed inverter can provide reactive power support. Extensive experimental results are performed on a laboratory-built hardware prototype to confirm the practicality of the proposed PV inverter.