ORIGINAL RESEARCH article
Front. Energy Res.
Sec. Smart Grids
Volume 13 - 2025 | doi: 10.3389/fenrg.2025.1582264
This article is part of the Research TopicModeling and Control of Power Electronics for RenewablesView all 8 articles
A Ground Current Suppression Method for Systems with a Large Number of Photovoltaic (PV) Inverters
Provisionally accepted
- 1Tianjin University, Tianjin, China
- 2Ginlong Technologies Co., Ltd, Ningbo, Zhejiang Province, China
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In large PV plants, a large number of PV inverters are linked together at grid-side to generate more power. However, as the number of PV inverter modules increases, the ground current problem worsens. This can result in a ground current fault, and cause the inverter failed and disconnected from the grid. In this paper, the solutions, including hardware and software, are proposed to suppress the ground current. The hardware solution is to connect filter capacitors back to the DC-bus, directing more ground current to the inverter rather than the grid to reduce the ground current. Additionally, the software solutions, including carrier phase shifting and carrier frequency shifting, are proposed. In the software solutions, the ground current for PV inverters can be cancelled each other, which can alleviate the ground current problem. In the paper, the system architecture is presented first. The concept of connecting the neutral point of the filter capacitors to the DC-bus midpoint is explained. The zerosequence mathematical model is then built. Moreover, the effect of the zero-sequence voltages of the DC/AC converter and the grid on the zero-sequence current is investigated. Then, the hardware solution is explained. The control architecture is presented, followed by an explanation of how to obtain the three-phase output voltage and zero-sequence components for PV inverters. Two software solutions, including carrier phase shifting and carrier frequency shifting, are detailed. Finally, the experiment is conducted to verify the theory.
Keywords: PV Inverters1, Ground Current Suppression2, Zero-sequence3, Carrier Phase Shifting4, Grid-Connected5
Received: 24 Feb 2025; Accepted: 18 Apr 2025.
Copyright: © 2025 Zhang, Donghui, Wang, Xu and Liu. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Wenping Zhang, Tianjin University, Tianjin, China
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