Open-phase detection circuit of three-phase power supply and high-voltage frequency converter

Abstract

The invention discloses an open-phase detection circuit of a three-phase power supply and a high-voltage frequency converter, and the detection circuit comprises a three-phase rectification unit which is used for rectifying a received three-phase alternating current so as to output a direct current signal; the open-phase detection unit is connected with the three-phase rectification unit and is used for carrying out open-phase detection on each phase of power supply of the three-phase alternating current so as to output an open-phase detection signal; the input end of the differential detection unit receives the direct current signal output by the three-phase rectification unit and is used for carrying out differential detection on the direct current signal so as to output a differential signal; and the control unit is used for determining a voltage effective value of the three-phase alternating current according to the differential signal and determining open-phase information of the three-phase alternating current according to the open-phase detection signal and the voltage effective value. Therefore, the circuit not only can detect the voltage effective value of the three-phase alternating current, but also can accurately judge the open-phase information of the three-phase alternating current, so that the real-time monitoring of the voltage condition of the three-phase alternating current is realized.

Description

technical field [0001] The invention relates to the technical field of high-voltage frequency converters, in particular to a phase loss detection circuit of a three-phase power supply and a high-voltage frequency converter. Background technique [0002] In the related art, the phase loss detection circuit of the high-voltage inverter uses whether the DC voltage output after the rectification of the three-phase AC voltage keeps the primary side of the optocoupler conducting, to judge whether the three-phase AC is lacking in phase, but this circuit can only judge the three-phase AC voltage. It is impossible to accurately determine which phase of the three-phase alternating current is missing whether the alternating current is phase-missing, which is inconvenient for the main control chip to diagnose the unit's fault and execute the reasonable logic of the system. At the same time, the phase loss detection circuit of the high-voltage inverter is prone to misjudgment with the un...

AI Technical Summary

Problems solved by technology

[0002] In related technologies, the high-voltage frequency converter phase loss detection circuit judges whether the three-phase AC power is out of phase by using the DC voltage output after rectifying the three-phase AC voltage to keep the primary side of the optocoupler conducting. However, this circuit can only judge the three-phase Whether the AC power is out of phase, it is impossible to accurately determine which phase of the three-phase AC power is missing, which is not convenient for the main control chip to diagnose the fault of the unit and execute the reasonable logic of the system

At the same time, the high-voltage inverter phase loss detection circuit is prone to misjudgment of undervoltage faults during the phase loss judgment process.

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