A comprehensive control method for H-MMC motor drive system operating at the same frequency

By using the integrated control method of the H-MMC motor drive system, the problem of unstable capacitor voltage in the bridge arm submodule was solved, achieving stable system operation and reduced losses. The control is simple and does not require the addition of circulating current.

CN116418274BActive Publication Date: 2026-05-29HUNAN UNIV
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
HUNAN UNIV
Filing Date
2023-03-08
Publication Date
2026-05-29

AI Technical Summary

Technical Problem

When the machine-side and grid-side frequencies of the H-MMC motor drive system are nearly identical, the differential frequency power of the bridge arm approaches infinity, causing unstable capacitor voltage in the bridge arm submodules, which may damage capacitors and other equipment. Existing solutions increase circulating current losses or control complexity.

Method used

A comprehensive control method for synchronous operation of the H-MMC motor drive system is adopted, including phase angle compensation calculation, machine-side speed control, grid-side power control, bridge arm submodule voltage stabilization and equalization control, and modulation wave calculation. Through simple control methods, the voltage fluctuation of the bridge arm submodule capacitor is suppressed, ensuring stable system operation.

Benefits of technology

It effectively suppresses voltage fluctuations in the bridge arm submodule capacitors, ensuring stable system operation. It eliminates the need for additional circulating current, reduces system losses, and simplifies the control method.

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Abstract

The application discloses a kind of H-MMC motor drive system comprehensive control method of same frequency operation.The H-MMC motor drive system includes: H-MMC, permanent magnet synchronous motor and AC power grid;System comprehensive control method of same frequency operation is mainly composed of compensation phase angle calculation, motor side speed control, grid side power control, bridge arm submodule voltage stabilization and voltage equalization control and modulation wave calculation 5 parts;The application gives the topological structure of H-MMC motor drive system, adjusts motor phase angle by real-time calculation compensation phase angle, to control H-MMC bridge arm difference frequency power tends to zero;Greatly reduce the requirement of circulation and neutral point voltage, without increasing controller, to realize the stable operation of system under same frequency working condition, with the advantages of small submodule capacitor voltage ripple, small loss, relatively simple control when same frequency operation.
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