Circuit and method for three-phase detection, and compressor

Patent metadata

Field	Value
Publication number	US-2016169952-A1
Application number	US-201514967534-A
Country	US
Kind code	A1
Filing date	Dec 14, 2015
Priority date	Dec 15, 2014
Publication date	Jun 16, 2016
Grant date	—

Abstract

A circuit for three-phase detection, a method for three-phase detection and a compressor are provided. The circuit for three-phase detection includes a first optical coupler and a second optical coupler. A first input end and a second input end of the first optical coupler are respectively connected to a first phase wire and a third phase wire of a power supply assembly, and a first output end of the first optical coupler provides a first output signal. A first input end and a second input end of the second optical coupler are respectively connected to a second phase wire and the third phase wire of the power supply assembly, and a first output end of the second optical coupler provides a second output signal. The first output signal and the second output signal are used to indicate a phase state of a three-phase alternating current of the power supply assembly.

First claim

What is claimed is:

1 . A circuit for three-phase detection, comprising a first optical coupler and a second optical coupler; wherein
a first input end and a second input end of the first optical coupler are respectively connected to a first phase wire and a third phase wire of a power supply assembly, and a first output end of the first optical coupler provides a first output signal; and a first input end and a second input end of the second optical coupler are respectively connected to a second phase wire and the third phase wire of the power supply assembly, and a first output end of the second optical coupler provides a second output signal; wherein the first output signal and the second output signal are used to indicate a phase state of a three-phase alternating current.

2 . The circuit for three-phase detection according to claim 1 , further comprising a micro control unit, wherein the micro control unit comprises a first input end and a second input end, wherein the first output end of the first optical coupler is connected to the first input end of the micro control unit, and the first output end of the second optical coupler is connected to the second input end of the micro control unit; and
the micro control unit is configured to detect, based on the first output signal and the second output signal, phase loss and/or phase reversal of the three-phase alternating current.

3 . The circuit for three-phase detection according to claim 1 , wherein
when the first output signal maintains a high electrical level and the second output signal is a square wave signal, it indicates that phase loss occurs in the first phase wire; when the second output signal maintains a high electrical level and the first output signal is a square wave signal, it indicates that phase loss occurs in the second phase wire; when the first output signal and the second output signal are square wave signals with a same phase, it indicates that phase loss occurs in the third phase wire; and when both the first output signal and the second output signal maintain high electrical levels, it indicates that phase loss occurs in at least two wires of the first, second, and third phase wires.

4 . The circuit for three-phase detection according to claim 1 , wherein the first output signal and the second output signal are square wave signals, and when a rising edge of the first output signal does not precede a rising edge of the second output signal by ⅓ of a period of the square wave signal, it indicates that phase reversal occurs in two wires of the first, second, and third phase wires.

5 . The circuit for three-phase detection according to claim 3 , further comprising:
a first sampling resistor, wherein the first input end of the first optical coupler is connected to the first phase wire through the first sampling resistor; a second sampling resistor, wherein the first input end of the second optical coupler is connected to the second phase wire through the second sampling resistor; and a third sampling resistor, wherein the second input end of the first optical coupler and the second input end of the second optical coupler are connected to the third phase wire through the third sampling resistor.

6 . The circuit for three-phase detection according to claim 5 , further comprising:
a first diode, connected between the first input end and the second input end of the first optical coupler; and a second diode, connected between the first input end and the second input end of the second optical coupler.

7 . The circuit for three-phase detection according to claim 5 , further comprising:
a first pull-up resistor, wherein the first output end of the first optical coupler is connected to a working voltage through the first pull-up resistor; and a second pull-up resistor, wherein the first output end of the second optical coupler is connected to the working voltage through the second pull-up resistor, wherein a second output end of the first optical coupler and a second output end of the second optical coupler are grounded.

8 . A compressor, comprising: a compression member, a motor, and a circuit for three-phase detection, wherein the motor is configured to drive the compression member to compress a medium that enters the compressor; and the circuit for three-phase detection is connected to the motor, and is configured to detect a phase state of the motor;
wherein the circuit for three-phase detection comprises a first optical coupler and a second optical coupler; wherein a first input end and a second input end of the first optical coupler are respectively connected to a first phase wire and a third phase wire of a power supply assembly for the motor, and a first output end of the first optical coupler provides a first output signal; and a first input end and a second input end of the second optical coupler are respectively connected to a second phase wire and the third phase wire of the power supply assembly, and a first output end of the second optical coupler provides a second output signal; wherein the first output signal and the second output signal are used to indicate the phase state of a three-phase alternating current of the power supply assembly for the motor.

9 . The compressor according to claim 8 , further comprising: a control module, configured to alarm and/or control on/off of the motor according to the phase state that is detected by the circuit for three-phase detection.

10 . The compressor according to claim 9 , further comprising a micro control unit, wherein the micro control unit comprises a first input end and a second input end, wherein the first output end of the first optical coupler is connected to the first input end of the micro control unit, and the first output end of the second optical coupler is connected to the second input end of the micro control unit; and
the micro control unit is configured to detect, based on the first output signal and the second output signal, phase loss and/or phase reversal of the three-phase alternating current.

11 . A method for three-phase detection, comprising:
receiving, by a first optical coupler, a signal of a first phase wire and a signal of a third phase wire that are from a power supply assembly, and outputting a first output signal according to the signal of the first phase wire and the signal of the third phase wire; receiving, by a second optical coupler, a signal of a second phase wire and the signal of the third phase wire of the power supply assembly, and providing a second output signal according to the signal of the second phase wire and the signal of the third phase wire; and detecting, based on the first output signal and the second output signal, a phase state of a three-phase alternating current of the power supply assembly.

12 . The method for three-phase detection according to claim 11 , wherein the detecting, based on the first output signal and the second output signal, the phase state of the three-phase alternating current comprises: detecting, based on the first output signal and the second output signal, phase loss and/or phase reversal of the three-phase alternating current.

13 . The method for three-phase detection according to claim 11 , wherein the detecting, based on the first output signal and the second output signal, the phase state of the three-phase alternating current comprises: detecting the phase loss of the three-phase alternating current according to at least one of the following:
when the first output signal maintains a high electrical level and the second output signal is a square wave signal, determining that phase loss occurs in the first

Assignees

• Danfoss Tianjin Ltd

Inventors

• Ma Zhenqiang
• Li Jingyuan
• Zeng Huapeng

Classifications

• G01R29/18 Primary

  Indicating phase sequence; Indicating synchronism · CPC title

• H02P2209/00

  Indexing scheme relating to controlling arrangements characterised by the waveform of the supplied voltage or current · CPC title

• H02P27/00

  Arrangements or methods for the control of AC motors characterised by the kind of supply voltage (of two or more motors H02P5/00; of synchronous motors with electronic commutators H02P6/00; of DC motors H02P7/00; of stepping motors H02P8/00) · CPC title

• H02P29/0241

  the fault being an overvoltage · CPC title