Synchronous phase-locked control method and device for doubly-fed gravity energy storage system under unbalanced grid voltage

By acquiring stator and rotor voltage and current from a doubly-fed gravity energy storage system, converting them to the αβ stationary coordinate system and extracting the positive sequence components, and combining a phase-locked loop (PLL) and a composite regulator, the problem of accurately synchronizing the rotation angle of a traditional PLL under an unbalanced power grid is solved, thus achieving stable control of speed and reactive power.

CN120638417BActive Publication Date: 2026-05-01STATE GRID JIANGSU ECONOMIC RES INST +1
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
STATE GRID JIANGSU ECONOMIC RES INST
Filing Date
2025-06-17
Publication Date
2026-05-01

AI Technical Summary

Technical Problem

Traditional phase-locked loop (PLL) technology cannot provide accurate synchronous rotation angles under unbalanced grid voltage, affecting the control accuracy and stability of doubly-fed induction generators. Especially in the context of increased grid fluctuations caused by the integration of new energy sources, it is difficult to balance filtering effect, response speed and control accuracy.

Method used

By acquiring the stator three-phase voltage, stator current, and rotor current of the doubly fed motor, converting them to the αβ stationary coordinate system and extracting the positive sequence voltage component, a synchronous rotation angle is generated. Combined with a phase-locked loop and a proportional-integral-complex resonant composite regulator, the reactive power reference value and rotor excitation voltage are calculated, and a converter switching signal is generated for synchronous phase-locked control.

Benefits of technology

Precise synchronous rotation angle and rotor excitation voltage control of the doubly fed gravity energy storage system under unbalanced grid voltage were achieved, ensuring the stability and control accuracy of speed and reactive power, and improving the system's anti-interference capability.

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Abstract

The application provides a synchronous phase-locked control method and device for a doubly-fed gravity energy storage system under unbalanced grid voltage, which obtains relevant parameters of a doubly-fed motor, generates a positive sequence component through band-pass filtering, Clarke transformation and dynamic filtering processing, generates a synchronous rotation angle by using a phase-locked loop, generates a rotor excitation voltage through coordinate transformation, PI control and a compound regulator, generates a switching signal through space vector modulation after superimposing excitation compensation, realizes stable control of the speed and reactive power of the doubly-fed motor, and guarantees the operation stability of the system under unbalanced grid voltage.
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Citation Information

Patent Citations

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  • Phase-locked loop implementation method used under voltage three-phase imbalance

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