Three-phase AC power supply phase sequence protection method, protection circuit, protector and air conditioner

Abstract

The invention provides a protective method, protective circuit and protector for a three-phase alternating-current power source phase sequence and an air conditioner. The protective method includes the following steps that a first-phase power source and a second-phase power source are input into a switching power circuit, so that a direct-current bias voltage, a direct-current reference voltage and a work voltage are obtained; the second-phase power source is divided through a first bleeder circuit and biased through the bias voltage, so that a first voltage signal is obtained, and a third-phase power source is divided through a second bleeder circuit and biased through the bias voltage, so that a second voltage signal is obtained; the first voltage signal is input into a first comparison circuit and compared with the reference voltage so that a first comparison signal can be obtained and the second voltage signal is input into a second comparison circuit and compared with the reference voltage so that a second comparison signal can be obtained; the first comparison signal and the second comparison signal are input into the clock input end and the data input end of a trigger circuit respectively, so that a protective signal is obtained. According to the protective method for the three-phase alternating-current power source phase sequence, inverse-phase protection, default-phase protection and under-voltage protection can be achieved and the method has the advantages of being simple and low in cost.

Description

technical field [0001] The invention relates to the field of power supply phase sequence protection, in particular to a three-phase AC power supply phase sequence protection method, a three-phase AC power supply phase sequence protection circuit, a three-phase AC power supply phase sequence protector and an air conditioner. Background technique [0002] In electrical control systems, undervoltage protection, phase loss protection and phase sequence protection are common protection functions of three-phase AC power supply. In the prior art, the monitoring and protection of the undervoltage, phase loss and phase sequence of the three-phase AC power supply are generally carried out by a microprocessor. This monitoring and protection method first performs square wave processing on the three-phase AC power supply to obtain The three-way signal is input into the single-chip microcomputer, and it is detected by the written software. It has comprehensive functions, but the price is ...

AI Technical Summary

Problems solved by technology

In the prior art, the monitoring and protection of the undervoltage, phase loss and phase sequence of the three-phase AC power supply are generally carried out by a microprocessor. This monitoring and protection method first performs square wave processing on the three-phase AC power supply to obtain The three-way signal is input into the single-chip microcomputer, and it is detected by the written software. It has comprehensive functions, but the price is expensive; for the monitoring and protection method that does not use the microprocessor, the detection method is complicated, and at least three-way comparators and For logic devices such as gates, the power supply of logic devices is obtained by dividing the resistance and capacitance, and the components used are many and have incomplete functions, which poses a safety hazard

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