Method for integrating frequency detection function of a three-phase converter software phase-locked loop

By employing a dual second-order generalized integrator filtering and vector calculation method, the problem of frequency detection response speed and accuracy in three-phase DC/AC converters was solved, achieving fast and accurate frequency detection and improving system stability and anti-interference capability.

CN122307190APending Publication Date: 2026-06-30启东沃太新能源有限公司
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
启东沃太新能源有限公司
Filing Date
2026-03-26
Publication Date
2026-06-30

AI Technical Summary

Technical Problem

The low bandwidth of the phase-locked loop in existing three-phase DC/AC converters results in slow frequency detection response and low accuracy, making it difficult to balance response speed and detection accuracy, and they are also susceptible to noise interference.

Method used

A dual second-order generalized integrator with adjustable center frequency is used for filtering and positive/negative sequence separation. Frequency detection is achieved by calculating the cross product, dot product, and angle of the positive sequence component vectors, combined with PARK transform and phase-locked loop feedforward value to replace the fixed feedforward.

Benefits of technology

It significantly improves the dynamic response speed and steady-state accuracy of frequency detection, enhances the tracking speed of the phase-locked loop for changes in grid frequency, balances system stability and dynamic performance, and saves software resources.

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Abstract

This invention discloses a method for integrating frequency detection function into a software phase-locked loop (PLL) of a three-phase converter, relating to the field of data processing. The method includes the following steps: Step S1, obtaining the grid voltage in a three-phase stationary coordinate system and converting it into a coordinate system grid voltage. Compared with existing technologies, the advantages of this invention are: This invention overcomes the limitations of low-bandwidth PLLs on frequency response, significantly improving the dynamic response speed and steady-state accuracy of frequency detection, while also possessing good anti-interference capabilities, solving the problem of balancing response speed and detection accuracy in traditional solutions; without changing the PLL PI parameters to ensure converter impedance stability and weak grid adaptability, the calculated real-time angular frequency is used as a feedforward value to replace the fixed feedforward, effectively improving the PLL's tracking speed for grid frequency changes; and it saves software resource costs.
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