Fully Parallel Embedded Z-Source Inverters Applied to Grid-Connected Photovoltaic Systems

Document Type : Research Paper

Authors

1 Department of Electrical Engineering, Shab.C., Islamic Azad University, Shabestar, Iran.

2 East Azarbaijan Electric Power Distribution Company, Tabriz, Iran.

Abstract

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.

Keywords

Main Subjects

References

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History

  • Receive Date: 01 July 2025
  • Revise Date: 03 September 2025
  • Accept Date: 24 September 2025

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