Method and device for judging alternating current power failure

Abstract

The invention provides a method and a device for judging alternating current power failure. The device comprises a sampling module, a processing module, a power failure counting module, a comparison module and a selection module, wherein the sampling module samples alternating current and stores sampling values in a first storage unit and a second storage unit; the processing module makes a difference between the nth (n is equal to 1, 2, 3, ..., and z) sampling value in the first storage unit and the nth (n is equal to 1, 2, 3, ..., and z) sampling value in the second storage unit, and reports the difference to the power failure counting module when the difference exceeds a set value; the power failure counting module records the times reported by the processing module; the comparison module judges whether the power fails according to the times recorded by the power failure counting module; and the selection module switches an output power supply after acquiring the power failure notification sent by the comparison module. The method and the device can quickly judge whether the alternating current power fails, and are simple and convenient to operate and high in accuracy.

Description

technical field [0001] The invention relates to an AC switching power supply technology, in particular to a method and device for judging AC power failure. Background technique [0002] At present, more and more electronic products need a stable AC power supply to ensure their normal operation. However, the mains power supply in many places is unstable, and power disturbances and interruptions often occur. Therefore, it is necessary to use an inverter to convert DC voltage to AC. Voltage, it can provide stable voltage for the load with or without mains input. In order to ensure that uninterrupted AC power can be provided to the load, it is necessary to quickly detect and judge the power failure of the mains, and then quickly switch to the inverter power supply. The current power-off detection is realized in this way: taking the mains (50Hz, 220V sinusoidal alternating current) as an example, the AD (converts analog signals into electrical signals) sampling circuit to measur...

AI Technical Summary

Problems solved by technology

The more the number of sinusoidal voltage segments of a cycle is divided, the more accurate the power-off judgment can be improved, but too many segments will lead to an increase in the false positive rate, and at the same time, an appropriate undervoltage gate is set for each segment of the sinusoidal voltage Limits can also increase the complexity of technical solutions and cause unnecessary errors

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