Research on Dynamic Vibration of Transformer With Wireless Power Transfer System Load

The total noise level of transformers is mainly influenced by harmonics in load current. The reasons are the interaction of harmonics with large load current at power frequency and the rising sound radiation efficiency with frequency. It is noted that the dynamic vibration behaviors under load harmonics operation are important to decrease the equipment noise. This paper mainly studies the vibration noise effects of three-phase three-leg transformer with the load of wireless power transfer (WPT) system, which would bring harmonics in the load current. Accelerometer sensors were arranged on the surface of the cores and windings of the transformer. Then, the vibration was measured in different positions of a transformer under the power of WPT system from 0 to 20 kW. The spectral distribution of vibration was obtained through the fast-Fourier transform analysis of the acquisition signals. The experimental results with and without PWT load imply that the harmonics in load-current have great effect on the vibration noise. It is to conclude that the main several harmonics of load current should be eliminated to reduce the vibration noise level.