纳米晶中频变压器振动来源及非正弦激励下噪声特性研究

To address the increasingly prominent issue of high-frequency noise generated by nanocrystalline medium-frequency transformers under non-sinusoidal excitation，and the fact that the overall vibration sources and noi-sec characteristics of the transformer remains unclear，in this paper the vibration measurements on the transformer core，windings，and clamping plates is carried out under both no-load and short-circuit conditions. The primary vibration sources and their transmission characteristics are identified. Furthermore，by measuring the sound pressure levels at the top surface and four side surfaces of the transformer under different voltage excitations，the major noise-radiating surfaces are determined，and the effects of excitation voltages on noise levels and spectral characteristics are analyzed. The research results show that in case of no load and short ciruit conditions the vibration amplitude of the transformer core is significantly higher than that of the windings and clamping plate，indicating that the core is the dominant vibration source. The vibrations are transmitted to the windings and clamping plate through structural coupling. In addition to the core，the windings and clamping plate are also important noise-radiating positions， where core vibrations induce structural vibrations and subsequent noise radiation through mechanical coupling. Moreover，the uneven distribution of local clamping pressure is the primary cause of the fundamental-frequency component observed in the vibration and noise signals.