Compressor three phase voltage phase sequence detection method

Abstract

The invention discloses a method for detecting phase sequence and lacking phase of three-phase alternating current for an air conditioner compressor, which comprises the following steps of: (1) falling edge determination stage for subjecting an air conditioner compressor to square wave shaping by using three-phase alternating current for determining a falling edge of one phase of the three-phase alternating current used for the air conditioner compressor; (2) delay comparison stage for detecting and delay-comparing the levels of the other two phases of alternating currents in the three-phase alternating current after square wave treatment according to the determined falling edge of the one phase of square wave as the reference; and (3) determination stage for determining whether the three-phase alternating current has error phase sequence, lacked phase or normal phase sequence. The three-phase current phase sequence detection logic adopted by the invention can accurately determine the phase sequence or phase lacking by detecting the voltages of the other two phases when meeting the falling edge, thus effectively protecting the compressor at low cost.

Description

technical field [0001] The invention relates to a phase sequence detection method of three-phase power for compressors, in particular to a phase sequence detection method and lack of phase of three-phase alternating current power for air conditioner compressors. Background technique [0002] Compared with other schemes, three-phase alternating current has more advantages in terms of power generation, transmission and industrial power consumption, so all countries in the world adopt three-phase alternating current. Usually the three-phase alternating current generated by the three-phase alternator is upgraded to three-phase high voltage by the three-phase transformer, which can reach 35KV or 10KV and other high-voltage graded transmission. 220KV and other transmission. No matter how high the voltage is transmitted, the voltage higher than 10KV must be stepped down to a single-phase voltage of 220V (line voltage 380V) by the last stage of user transformers for users to use. T...

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Problems solved by technology

[0007] At present, the air conditioners with practical three-phase power supply compressors produced by LGTEA all have the function of detecting the three-phase electric phase sequence of the compressor R, S, and T. The detection logic is as follows: figure 1 As shown, the three-phase voltages of R, S, and T are subjected to shaping and square-wave processing and compared. When the R-phase voltage is the highest in a certain period of time, the R-phase signal received by the corresponding microcontroller is 1, and the other two-phase signals are 0. The same reason When the S-phase voltage is the highest, the S signal is 1. When the value of (R, S, T) changes as follows, the phase sequence of the three-phase electricity is correct, that is, (1, 0, 0) becomes (0, 1, 0) Change to (0, 0, 1). Although the electric control board can accurately determine the phase sequence of the three-phase power used by the compressor, it needs to rely entirely on imports, and the cost is high, which is not conducive to popularization and application.

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