Design and Implementation of a Y-Source Micro-Inverter using a New Topology

Abstract

Photovoltaic (PV) system architectures are being designed to optimize the extraction of energy. Micro-Inverter architectures are gaining in popularity as they are increasing the efficiency and the power extracted from the PV module and mitigate the shading effect. This work details the design of a proposed DC-AC micro-inverter. The design incorporates a combination between a virtual DC bus inverter and proposed three-winding coupled transformer which is based on Y-source impedance configuration. A high voltage spikes and low voltage regulation arises from loose coupled inductors in the ferrite core. On the other side, transformer elimination in the micro-inverter configurations can generate high common-mode voltage as a consequence, leakage current can cause distortion of the grid current. In this work, the developed transformerless micro-inverter can overcome all the drawbacks mentioned above. The proposed micro-inverter has been developed and designed to eliminate both the leakage inductance due to three-winding coupled transformer and leakage current due to using transformerless micro-inverter configuration. In addition to that the converter reduced the components stress significantly and increases the converter voltage gain capability in one single-stage. A detailed mathematical model of the micro-inverter has been developed and proved using Mathematica 11.2 software. To evaluate the performance of the micro-inverter and illustrate the features, PLECS 4.2 simulation software has been used, which is shows a preference for the proposed micro-inverter over the traditional impedance source inverters in terms of boosting capability and components voltage stress. To validate the simulation results of the proposed micro-inverter, a 25W prototype of microinverter has been verified experimentally.