A Grid-Connected Single-Phase Transformerless Inverter Controlling Two Solar PV Arrays Operating Under Different Atmospheric Conditions

A grid-connected single-phase transformer-less inverter that can operate two serially connected solar photovoltaic (PV) subarrays at their respective maximum power points while each one of them is exposed to different atmospheric conditions is proposed in this paper. As two subarrays are connected in series, the number of serially connected modules within a subarray is reduced to half. Reduction in the number of serially connected PV modules within a subarray leads to an overall improvement in the magnitude of power that can be abstracted from a subarray while the modules of the subarray are exposed to varied atmospheric conditions. The topological structure of the inverter ensures that the common mode voltage does not contain high-frequency components, thereby reducing the magnitude of leakage current involved with the solar panels well within the acceptable limit. An in-depth analysis of the scheme along with the derivation of its small signal model has been carried out. Detailed simulation studies are performed to verify its effectiveness. A 1-kW laboratory prototype of the scheme has been fabricated. Detailed experimental validations have been carried out utilizing the prototype to confirm the viability of the proposed scheme.