Under-voltage protection fault of ls power generation inverter

1. Does the inverter alarm the fault number 12 (undervoltage fault)?

2. Test whether the input power supply is undervoltage.

3. Test whether the mainstream bus voltage is around 550.

Under-voltage fault is due to the low grid voltage or the low DC bus conductor, and there are errors in the self-test of frequency converter, such as motherboard and power supply detection.