fully parallel embedded z-source inverters applied to grid-connected photovoltaic systems

This paper presents a performance-enhanced control strategy for fully parallel embedded z-source (fpez) inverters in grid-connected photovoltaic (pv) systems. unlike traditional z-source inverters, the fpez topology embeds two isolated dc sources in series with each inductor of the x-shaped network, enabling the use of two pv panels and resulting in a smoother dc input current, reduced capacitor voltage stress, and an improved dynamic response under irradiance variations. the proposed control system consists of two parts: a slope-based (dp/dv) maximum power point tracking (mppt) algorithm to regulate the shoot-through time, and a p–q current control method to generate the reference current. this dual approach ensures the injection of high-quality power into the grid while maintaining the dc-link capacitor voltage at its reference value. simulation results in pscad/emtdc validate the robust performance of the proposed structure and control strategy under partial shading and grid disturbances. the outcomes demonstrate a total harmonic distortion (thd) of less than 0.5%, a unity power factor, and stable dc-link voltage regulation at approximately 550 v, confirming the system's viability for high-efficiency, grid-compliant pv applications.