1. When the mains power is normal, the mains power will supply power to important loads through the mutual switching device, and at the same time, the mains power detection and battery charging management will be carried out, and then the battery pack will provide DC energy to the inverter. Here, the charger is a small power DC power supply that only needs to provide a charging current equivalent to 10% of the battery pack capacity (Ah) to the battery pack, and it does not have the ability to directly provide DC power to the inverter. At this time, the municipal power supplies power to various emergency loads of users through the power supply system composed of EPS AC bypass and transfer switch. At the same time, under the control of EPS logic control board, the inverter stops working and is in the automatic shutdown state. Under this condition, the power supply actually used by the user load is the mains power from the grid. Therefore, the EPS emergency power supply is also usually said to work in a sleep state all the time, which can effectively achieve the effect of energy conservation.
2. When the mains power supply is interrupted or the mains voltage exceeds the limit (± 15% or ± 20% of the rated input voltage), the mutual transfer device will immediately switch to the inverter for power supply. With the support of the DC energy provided by the battery pack, at this time, the power used by the user load is the AC power converted by the EPS inverter, not from the mains power.
3. When the mains voltage returns to normal operation, the control center of EPS sends a signal to automatically shut down the inverter, and at the same time, it performs the switching operation from inverter power supply to AC bypass power supply through its change-over switch. After that, while EPS provides mains power to the load through the AC bypass power supply channel, it also charges the battery pack through the charger.
