Photovoltaic inverter low voltage ride through current control method and control device

By adjusting the output current component of the photovoltaic inverter, and utilizing Lagrange's theorem and iterative optimization algorithms, the problem of photovoltaic inverter synchronization failure with the grid under weak grid conditions was solved, achieving stable operation of the photovoltaic inverter during low voltage ride-through and improving grid stability.

CN122118920APending Publication Date: 2026-05-29SHANGHAI CHINT POWER SYST CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
SHANGHAI CHINT POWER SYST CO LTD
Filing Date
2026-03-25
Publication Date
2026-05-29

AI Technical Summary

Technical Problem

Under weak grid conditions, photovoltaic inverters are prone to instability during low voltage ride-through caused by grid faults. Traditional phase-locked loops fail, leading to the failure of photovoltaic inverter synchronization with the grid and triggering a chain reaction of instability risks.

Method used

By adjusting the d-axis and q-axis current components of the photovoltaic inverter's output current, and based on the difference between the real-time grid voltage and the preset voltage threshold, the output current is adjusted using Lagrange's theorem and an iterative optimization algorithm to achieve synchronization between the grid and the photovoltaic inverter.

Benefits of technology

It effectively solves the problem of phase-locked loop instability of photovoltaic inverters under weak grid faults, ensuring that photovoltaic inverters are synchronized with the grid during low voltage ride-through and improving grid stability.

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Abstract

The embodiment of the present application provides a kind of photovoltaic inverter low voltage ride-through current control method and control device.The method comprises: obtaining grid real-time voltage and the output current of photovoltaic inverter;According to the difference between grid real-time voltage and preset voltage threshold, adjust the d-axis current component and / or q-axis current component of the output current of photovoltaic inverter, so that grid real-time voltage and the output voltage of photovoltaic inverter are synchronized, realize the low voltage ride-through of photovoltaic inverter.The technical scheme provided by the embodiment changes the d-axis current component and / or q-axis current component of the output current of photovoltaic inverter, so as to avoid that the output current is too large to cause unstable current control, control grid real-time voltage and the output voltage of photovoltaic inverter are synchronized, thereby improve the stability of photovoltaic inverter output voltage, and then improve the stability of grid under the condition of photovoltaic inverter phase-locked loop failure under grid fault.
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