Standby power supply and method for operating same

A method for operating a standby power supply, comprising:

• at a controller coupled to the standby power supply, the standby power supply comprising:
• a first sub power supply configured to provide alternating current electrical energy, wherein the first sub power supply is connected to an input terminal of an AC/DC converter, the AC/DC converter configured to convert the alternating current electrical energy into direct current electrical energy, wherein an output terminal of the AC/DC converter is connected to an output terminal of the standby power supply;
• a first switch, wherein the first sub power supply is connected to the input terminal of the AC/DC converter via the first switch;
• at least one second sub power supply configured to provide direct current electrical energy in parallel to an output of the AC/DC converter;
• at least one second switch, wherein the at least one second sub power supply is connected to the output terminal of the standby power supply via the at least one second switch respectively;
• and a third switch operable to connect an alternating current power grid to the input terminal of the AC/DC converter;
• determining by the controller a voltage of the alternating current power grid;
• determining by the controller a power threshold Pthreshold according to the following formula:
• Pthreshold=Paverage*a+Ppeak*(1−a),
• wherein Paverage is average power required for a power supply load, which is statistically determined by the controller based on load data measured per minute from the standby power supply;
• Ppeak is peak power of the power supply load, which is statistically determined by the controller based on load data measured per second from the standby power supply;
• and a is a proportional coefficient, 0<a<1, by which the power threshold is adjusted;
• determining whether the voltage of the alternating current power grid connected via the third switch is lower than a voltage threshold;
• in response to the voltage of the alternating current power grid is lower than the voltage threshold, determining whether expected output power of the standby power supply is less than or equal to Pthreshold;
• in response to the voltage of the alternating current power grid is lower than the voltage threshold and expected output power of the standby power supply is less than or equal to Pthreshold, closing the first switch and open the at least one second switch to supply power using the first sub power supply;
• and
• in response to the voltage of the alternating current power grid is lower than the voltage threshold and the expected output power of the standby power supply is greater than Pthreshold, closing the first switch and the at least one second switch to supply power using both the first sub power supply and the at least one second sub power supply.