LOW VOLTAGE RIDE-THROUGH METHOD FOR PHOTOVOLTAIC UNITS BASED ON LSTM-OPTIMIZED VIRTUAL IMPEDANCE

Man Jiawei; Zhi Yuemei; Liu Chuang; Hu Jiheng; Zhang Hui; Fang Xuan

doi:10.19912/j.0254-0096.tynxb.2024-0397

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Acta Energiae Solaris Sinica ›› 2025, Vol. 46 ›› Issue (7) : 636-644. DOI: 10.19912/j.0254-0096.tynxb.2024-0397

Special Topics of Academic Papers at the 95th Annual Meeting of the China Association for Science and Technology

LOW VOLTAGE RIDE-THROUGH METHOD FOR PHOTOVOLTAIC UNITS BASED ON LSTM-OPTIMIZED VIRTUAL IMPEDANCE

Man Jiawei¹, Zhi Yuemei², Liu Chuang¹, Hu Jiheng², Zhang Hui², Fang Xuan²

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Abstract

In response to the voltage drops caused by short-circuit faults in the power grid, which can lead to power-angle instability and overcurrent phenomena in inverters, this paper proposes an active support low-voltage ride-through（LVRT）approach for photovoltaic （PV） units to traverse low voltage based on long short-term memory networks（LSTM） optimized virtual impedance. Firstly, a grid-forming active support control strategy for PV arrays is proposed by consider the output characteristics of the PV array. Secondly, transient voltage regulation equations are introduced based on traditional virtual synchronous generator（VSG） technology to construct a third-order synchronous generator model. Then, a fault discriminator is used to determine the operating state of the system and determine the switching time of the virtual impedance. The magnitude of the virtual impedance is determined by combining the relationship between the virtual impedance and the grid voltage of the PV unit using an LSTM-based prediction method. Finally, a PV grid-connected system is built on the DIgSILENT/PowerFactory power system simulation platform for validation. The superiority of the proposed method is demonstrated through comparative analyses.

Key words

photovoltaic system / fault current / transient stability / LSTM / low voltage ride-through

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Man Jiawei, Zhi Yuemei, Liu Chuang, Hu Jiheng, Zhang Hui, Fang Xuan. LOW VOLTAGE RIDE-THROUGH METHOD FOR PHOTOVOLTAIC UNITS BASED ON LSTM-OPTIMIZED VIRTUAL IMPEDANCE[J]. Acta Energiae Solaris Sinica. 2025, 46(7): 636-644 https://doi.org/10.19912/j.0254-0096.tynxb.2024-0397

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