A Quasi Z -Source Matrix Microinverter for Grid Connected PV Applications

摘要

Over the past few years, Microinverters have gained interest in the area of PV power conversion, this since the direct connection of modules to the grid can increase overall harvested energy in comparison with other power conditioning approaches. Moreover, microinverters which are essentially modular, allow the system to grow over time and result in a more reliable solar plant. In the implementation of a microinverter system important features are its overall voltage gain, to allow interfacing the low voltage PV module to the grid and its power conversion efficiency. The traditional approach to achieve these two aspects is to use a two-stage system where a fly-back converter is cascaded with a single-phase inverter, which has drawbacks such as a discontinuous input current with high second harmonic ripple, high EM noise, high semiconductor stress, and reduced efficiency. In this paper, a single-stage quasi-Z source push-pull matrix microinverter system is presented to deal with some of these drawbacks. Resulting in a high-performance microinverter topology which produces the required voltage gain, while having continuous input current and a high-quality output.