What is the working principle of the vehicle emergency power supply?

The emergency power supply adopts single-cell inverter technology, integrating charger, battery, inverter, and controller.

(1) When the mains power is normal, the mains power is used to supply power to important loads through the mutual switching device, while the mains power detection and battery charging management are carried out, and then the battery pack provides DC energy to the inverter. Here, the charger is a low-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. It does not have the ability to directly provide DC power to the inverter. At this time, the main power is supplied to the user's various emergency loads through the power supply system composed of the EPS AC bypass and transfer switch.

At the same time, under the control of the EPS logic control board, the inverter stops working and is in an automatic shutdown state. Under this condition, the power actually used by the user's load is the mains power from the power grid. Therefore, the EPS emergency power supply is also usually said to be always working in a sleep state, which can effectively achieve energy-saving effects.

(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 switching device will immediately switch to the inverter power supply. With the support of the DC energy provided by the battery pack, the power used by the user load is the AC power converted by the EPS inverter, rather than from the mains.

(3) When the mains voltage returns to normal operation, the EPS control center sends a signal to automatically shut down the inverter and also switches from inverter power supply to AC bypass power supply through its transfer switch. After that, the EPS provides mains power to the load through the AC bypass power supply path while also charging the battery pack through the charger.