Method and device for phase lack detection of three-phase circuit

Abstract

The invention discloses a phase-lack detecting method used for a three-phase circuit, including the following steps: a. an instantaneous value of the three-phase AC voltage is sampled to get a three-phase coordinate; b. a coordinate conversion is carried out to convert the three-phase coordinate into a two-phase coordinate; c. an amplitude computation for the two-phase coordinate is carried out to get the amplitude; d. the amplitude is compared with a preset amplitude corresponding to the lower limit of a preset voltage range; if the amplitude is less than the preset amplitude corresponding to the lower limit of the preset voltage range, the phase-lack can be judged; if not, the step a is reverted to carry out the phase-lack detecting process again. The invention also discloses an apparatus used for the phase-lack detection of the three-phase circuit, comprising a collecting module, a coordinate conversion module, an amplitude computing module and a detecting module. The method and apparatus of the invention realize the phase-lack detection by a software means and both operation and maintenance are simple and the equipment cost can be reduced.

Description

technical field [0001] The invention relates to the field of phase loss protection for three-phase power supply, in particular to a method and device for phase loss detection of three-phase power supply equipment such as motors and switching power supplies. Background technique [0002] The three-phase mains power supply method is widely used in motors and switching power supplies. Due to the grid itself or unreliable power input wiring, one or more phases of the three-phase AC input will be interrupted. At this time, the motor or switching power supply is in a phase-opening state. When the power supply runs with a lack of phase, it will cause damage to the motor or switching power supply. Therefore, phase loss protection must be carried out for the power supply. In the phase loss protection, the key factor is whether the phase loss of the three-phase mains can be quickly detected, so as to perform phase loss protection in time. [0003] The currently used phase loss detec...

AI Technical Summary

Problems solved by technology

[0002]The three-phase mains power supply method is widely used in motors, switching power supplies, etc. Due to the grid itself or the unreliable power input wiring, it will cause some failures in the three-phase AC input. Interruption of one or more phase inputs

[0004]Aiming at the current method of using hardware detection circuit for phase loss detection, the equipment adds external hardware, increases the cost, and increases the complexity of equipment maintenance

At present, there is a lack of a convenient and accurate method for phase loss detection through software

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