Study on the Suppression Mechanism of Vibration and Noise in Converter Transformers Under Multi-Physical Field Coupling Using Different Filtering Strategies

Electromagnetic vibration and noise issues of converter transformers under harmonic operating conditions have become increasingly prominent. To enable a systematic comparison of different filtering strategies, this paper establishes a multiphysical field coupling model incorporating electromagnetic, structural, and acoustic fields, and systematically investigates four filtering configurations: grid-side LC filtering, valve-side LC filtering, inductive filtering, and valve-side capacitive filtering through theoretical analysis, finite-element simulation, and experimental verification on a 12-pulse laboratory HVDC prototype platform. The simulation results show that the maximum vibration acceleration decreases from 3.06 m/s² under the no-filter condition to 1.02 m/s² under valve-side capacitive filtering. Experimental measurements further confirm the suppression effect, with the vibration acceleration at Point 8 decreasing from 2.28 m/s² to 0.42 m/s², corresponding to a reduction of approximately 82%, while the average A-weighted sound pressure level decreases from 66.1 dB to 58.1 dB. These results indicate that vibration and noise suppression cannot be evaluated solely by total harmonic distortion; the attenuation and distribution of individual harmonic components should also be considered. The findings provide a theoretical and engineering basis for the vibration and noise reduction design of converter transformers.