Taking HIGHIDEA H-series power frequency power inverter as an example, it may not operate normally when only connected to the AC power supply. The reasons are analyzed as follows:
Online working mode: When the grid's mains power is normal, the AC mains power first needs to go through rectification and filtering, and then be inverted by the inverter into pure AC power to supply the rear-end loads. When the grid's mains power is abnormal or experiences an outage, the DC power provided by a DC panel or other equipment is inverted by the inverter into AC power to supply the rear-end loads. Thus, when only connected to AC power, it cannot function properly during mains power abnormalities or outages.
Standby working mode: When the grid's mains power is normal, the AC mains power directly supplies the loads through a static transfer switch. When the grid's mains power is abnormal or experiences an outage, the DC power provided by a DC panel or other equipment needs to be inverted by the inverter into AC power to supply the rear-end loads. With only an AC connection, it also cannot operate normally during mains power abnormalities or outages.
Pure inverter working mode: The inverter is required to convert DC power into AC power for use in scenarios such as supplying AC loads. Simply connecting it to AC power does not meet the requirements of this working mode, and it will not operate normally either.