Since solar energy is created during the daytime, inverters will be completely silent at night.
With the advancement in technology, solar arrays generally make little to almost no audible noise.
Some inverters can make noise that is described as lower than the decibel level of a refrigerator or air conditioner, but the sound decreases as distance increases. The sound itself is more like a low hum.
Inverters for large arrays, as in the case of solar farms, do generate more noise but only up close. If tracking was implemented with the large solar farms, you can hear a subtle noise as the trackers adjust the solar panels.