BACKUP POWER SYSTEM, AND METHOD FOR DETECTING TURN-ON OF MANUAL BYPASS CIRCUIT BREAKER

This application pertains to the field of power electronics technologies, and provides a backup power system and a method for detecting turn-on of a manual bypass circuit breaker. In the solutions provided in this application, on a premise that an on/off-grid relay in an on/off-grid controller is turned off, if detecting that a difference between voltages at two ends of the manual bypass circuit breaker (namely, a bypass air switch) is less than a second threshold, a control circuit can determine that a voltage at an inverter-side port of the on/off-grid controller and a voltage at a power grid-side port are close. In this case, if both the voltage at the inverter-side port and the voltage at the power grid-side port are greater than a first threshold, and if detecting that an inverter is in a non-operating state, the control circuit can further determine that the voltage at the inverter-side port is provided by a power grid via the turned-on bypass air switch. Therefore, the control circuit can accurately determine that the bypass air switch is in a turned-on state, and send an alarm signal. The detection method can effectively avoid false detection, and ensure high accuracy of detecting the turned-on state of the bypass air switch.