A method and device for suppressing high-frequency oscillation of MMC-HVDC system

By optimizing the design of a third-order high-pass filter in the MMC-HVDC system, the high-frequency oscillation problem caused by non-minimum phase characteristics was solved, effectively suppressing high-frequency oscillation and reducing fundamental power loss, thereby improving the stability and adaptability of the system.

CN121983993BActive Publication Date: 2026-07-24NORTHEAST DIANLI UNIVERSITY
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
NORTHEAST DIANLI UNIVERSITY
Filing Date
2026-04-07
Publication Date
2026-07-24

AI Technical Summary

Technical Problem

The existing high-frequency oscillation suppression strategy of MMC-HVDC system does not fully consider the non-minimum phase characteristics, resulting in the expansion of negative damping characteristics. It is difficult to reduce the fundamental active power loss while effectively suppressing high-frequency oscillations, and it has poor adaptability to grid operating conditions.

Method used

By constructing a high-frequency impedance model of the MMC-HVDC system with control link delay, a third-order high-pass filter is optimized and connected in parallel at the common connection point (PCC) to provide -90° phase compensation, reduce active power loss at the fundamental frequency, and verify that the filter is a minimum phase system through the Routh criterion, thus achieving impedance reshaping.

Benefits of technology

It effectively suppresses high-frequency oscillations in the 1000-2500Hz range, reduces fundamental active power loss, improves system stability and robustness, adapts to different power grid operating conditions, and has little impact on steady-state and transient characteristics.

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Abstract

The application discloses a high-frequency oscillation suppression method and device of an MMC-HVDC system, and belongs to the technical field of flexible direct current power transmission system stability control; in view of the problem that the non-minimum phase characteristic of the MMC is caused by the control link delay, and further causes high-frequency oscillation of 1000-2500 Hz, a high-frequency impedance model of the system containing the delay is constructed, and the oscillation mechanism dominated by the non-minimum phase characteristic is determined; a third-order high-pass filter is connected in parallel with the PCC point of the MMC and the alternating current power grid, filter parameters are optimized, -90° phase compensation is realized in a negative damping interval, and the fundamental active power loss is reduced; the impedance characteristic is researched through an impedance detection method, high-frequency oscillation risk is judged, and remodeling effect is verified to suppress the oscillation; the application fundamentally eliminates the negative damping characteristic of the system, the suppression effect is better than that of a traditional passive filter, the influence on the steady-state and transient-state characteristics of the system is small, the application is suitable for different power grid working conditions, and the engineering practicability is high.
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