There are two working principles of wall mounted battery system: one is to use mains power to convert AC to DC; The other uses direct current.
1. AC to DC
When the mains voltage is converted into the designed voltage through the input switch connected to the transformer, it enters the pre voltage stabilizing circuit. The pre voltage stabilizing circuit is used to preliminarily stabilize the required output voltage. Its purpose is to reduce the voltage drop between the input and output of the high power regulator tube（powerwall 20 kwh）, reduce the power consumption of the high-power regulator tube, and improve the working efficiency of the DC power supply, The pre stabilized voltage power supply is generally stabilized by the tap of the relay switching transformer output of the silicon controlled stepless phase shift adjustment type. After the pre stabilized power supply and filter ①, the voltage is basically stable, and the DC current with relatively small ripple is accurately and rapidly applied to the top voltage of the high-power regulator controlled by the control circuit. Then, the DC voltage with voltage stabilization accuracy and performance meeting the standards is filtered by the filter ② to obtain the output DC power I need. In order to obtain the output voltage or current value I need, We also need to sample and detect the output voltage and current values and transmit them to the control/protection circuit. The control/protection circuit will compare the detected output voltage and current values with the values set by the voltage/current setting circuit, and then drive the pre voltage stabilizing circuit and high-power regulator to enable the DC voltage stabilizing power supply to output the voltage and current values set by us, At the same time, when the control/protection circuit detects abnormal voltage or current value, it will start the protection circuit to make the DC power supply enter the protection state.
2. DC power supply
The two AC incoming lines output one AC (or only one AC incoming line) through the switching device to supply power to each charging lifepo4 48v 200ah module. The charging module converts the input three-phase AC power into DC power to charge the battery and supply power to the load of the closing bus. In addition, the closing bus supplies power to the control bus through the step-down device (some design schemes do not require the step-down device).