Investigation of single-stage transformerless buck-boost microinverters

Abstract

The conventional microinverters with transformers and multiple-stage system increases the cost, weight and size, lowering the effectiveness and power density of PV system. It is therefore desirable to prevent using these methods for a microinverter. However, extra care must be taken to prevent component stress, excess switching and conduction losses, ground leakage currents and harmonics. Several transformerless buck-boost inverters have lately been suggested to address various issues. Due to the availability of a number of buck-boost inverter-topology for the solar PV system, it is often difficult to identify when to choose the appropriate topology. Therefore, in order to present a clear view of the advancement of transformerless buck-boost inverters for next-generation grid-integrated PV systems, this article seeks to explore multiple buck-boost topologies with an extensive analytical comparison. Computer simulations for the 70 W system have been conducted in PLECS software to strengthen the results and comparisons, as well as to provide more insight into the features of the distinct topologies for the building-integrated photovoltaic implementation. At the later part, voltage and current stress in each component, efficiency and total harmonic distortion of the system are provided with a general summary, as well as, a technology roadmap.