Phase-lack and low-voltage detection circuit for three-phase alternating current

Abstract

The invention relates to a phase-lack and low-voltage detection circuit for three-phase alternating current, and belongs to the technical field of power electronic products. The phase-lack and low-voltage detection circuit comprises three groups of phase detection circuits and a comparison output circuit, wherein the three groups of phase detection circuits are connected in parallel; the input end of each group of phase detection circuits is respectively connected with a phase alternating current input end of the three-phase alternating current in a power grid to be detected for respectively detecting phase-lack and low-voltage of the phase alternating current input; output ends of the three groups of phase detection circuits are connected with the input end of the comparison output circuit after being connected mutually, and a detection result is output by the comparison output circuit; each group of phase detection circuits comprises a rectifying circuit, a current-limiting circuit, an amplitude-limiting circuit, an opto-coupling isolating circuit, a charging and discharging circuit and an isolating circuit which are connected in sequence, wherein the input end of the rectifying circuit and the other input end of the opto-coupling isolating circuit are respectively connected with both ends of each phase alternating current. The phase-lack and low-voltage detection circuit has the characteristics that a two-in-one function of phase-lack detection and input low-voltage detection is realized, the circuits are simple, power consumption is very little, SMT (Surface Mounted Technology) can be realized and embedded in equipment, and the like.

Description

technical field [0001] The invention belongs to the technical field of power electronic products, and in particular relates to the design of a phase-loss and low-voltage detection circuit of three-phase alternating current. Background technique [0002] In the field of power electronic products, high-power equipment generally adopts three-phase AC power supply, such as: electric drive equipment, high-power power supply system, UPS power supply system, electrical equipment system, etc. , the question of how to work. At this time, if the circuit is not protected in time, these valuable equipment will face the danger of being burned, and once it happens, it will bring huge losses to production and organization. Therefore, the phase loss and low voltage detection circuit of three-phase AC is to protect these equipment indispensable. [0003] The traditional phase-loss and low-voltage detection circuit method of three-phase AC is to use three transformers to isolate and detect ...

AI Technical Summary

Problems solved by technology

At this time, if the circuit is not protected in time, these valuable equipment will face the danger of being burned, and once it happens, it will bring huge losses to production and organization. Therefore, the phase loss and low voltage detection circuit of three-phase AC is to protect these equipment indispensable

[0003] The traditional phase-loss and low-voltage detection circuit method of three-phase AC is to use three transformers to isolate and detect the voltage of each phase of AC separately. It is far from suitable for the requirements of small size, light weight, and micro power consumption required by modern equipment, let alone the requirements for embedding in equipment

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