Phase loss detection device, compressor including the same, and phase loss detection method

Patent metadata

Field	Value
Publication number	US-12155382-B2
Application number	US-202016811301-A
Country	US
Kind code	B2
Filing date	Mar 6, 2020
Priority date	Mar 7, 2019
Publication date	Nov 26, 2024
Grant date	Nov 26, 2024

Abstract

A phase loss detection device, a compressor including the same, and a phase loss detection method are disclosed. The phase loss detection device may include a signal converting circuit and a processor. The signal converting circuit is configured to convert voltage signals corresponding to respective phases of multiphase alternating current (AC) power monitored from a motor. The processor is configured to receive the converted voltage signals from the signal converting circuit, and configured to calculate, based on the converted voltage signals, one or more phase angles between the respective voltage signals. The processor is configured to determine that phase loss occurs if any one or more of the calculated phase angles deviate from a nominal value of a corresponding phase angle of the multiphase AC power by a value higher than a predetermined threshold. The phase loss detection can be performed in a convenient, effective and reliable way.

First claim

What is claimed is:

1. A phase loss detection device for a motor in a compressor, wherein the phase loss detection device is provided inside a shell of the compressor, comprising:
a monitoring port, configured to receive a respective voltage signal corresponding to a respective phase of multiphase AC power monitored from the motor;
a signal converting circuit configured to convert the respective voltage signal; and
a processor configured to receive the voltage signal converted from the signal converting circuit and configured to:
calculate, based on the voltage signal converted, one or more phase angles between voltage signals; and
determine that phase loss occurs if any one or more of the phase angles deviate from a nominal value of a corresponding phase angle of the multiphase AC power by a value higher than a predetermined threshold;

wherein
the monitoring port is configured to receive a first voltage signal corresponding to a first phase of the multiphase AC power monitored from the motor, a second voltage signal corresponding to a second phase of the multiphase AC power monitored from the motor, a third voltage signal corresponding to a third phase of the multiphase AC power monitored from the motor;
the signal converting circuit comprises:
a first optocoupler, configured to receive at its anode end the first voltage signal through a first resistance, and to receive at its cathode end the second voltage signal through a second resistance, and configured to output a low-level if its input diode is on and to output a high-level if its input diode is off;
a second optocoupler, configured to receive at its anode end the second voltage signal through a third resistance, and to receive at its cathode end a third voltage signal through a fourth resistance, and configured to output a low-level if its input diode is on and to output a high-level if its input diode is off; and
a third optocoupler, configured to receive at its anode end the third voltage signal through a fifth resistance, and to receive at its cathode end the first voltage signal through a sixth resistance, and configured to output a low-level if its input diode is on and to output a high-level if its input diode is off.

2. The phase loss detection device according to claim 1 , wherein the voltage signal is one of a phase voltage and a line voltage of the motor.

3. The phase loss detection device according to claim 1 , wherein the multiphase AC power is three-phase AC power, the nominal value is 120°, and the threshold is 4% of the nominal value.

4. The phase loss detection device according to claim 1 , wherein the processor is configured to calculate the phase angle by:
calculating a period of the voltage signal;
determining a difference in time between any two voltage signals, and determining the phase angle between the two voltage signals according to the difference and the calculated period.

5. The phase loss detection device according to claim 1 , wherein the signal converting circuit comprises a pulse generator circuit configured to generate, based on the voltage signal, a pulse waveform with a same period and same phase as a waveform of the voltage signal.

6. The phase loss detection device according to claim 5 , wherein the pulse generator circuit comprises:
an optocoupler comprising: an input side photodiode configured to receive the voltage signal or to receive a voltage proportional to the voltage signal, and an output side transistor configured to output, at an output node, a low level if the input side photodiode is on, or to output a high level if the input side photodiode is off.

7. A compressor, comprising:
a compression component configured to compress suctioned gas and discharge the compressed gas;
a motor configured to drive the compression component;
a phase loss detection device recited in claim 1 ; and
a protection switch configured to switch on to turn off the motor if the phase loss detection device detects phase loss.

8. The compressor according to claim 7 , wherein the compressor is a scroll compressor, wherein, the motor is connected to power supply through a contactor K 1 , and wherein the monitoring port is configured to receive the respective voltage signal from a connecting node between the contactor and the motor;
wherein the phase loss detection device further comprises a protection switch, arranged in a power supply line through the contactor, and wherein if phase loss is detected, the protection switch is configured to be “on” in order to enable the contactor to disconnect power from the power supply to the motor.

9. The phase loss detection device of claim 1 , wherein:
the phase loss detection device is able to detect whether the motor has phase loss during running of the compressor.

10. A compressor comprising:
a shell; and
the phase loss detection device of claim 1 ;
wherein the phase loss detection device is provided inside the shell of the compressor.

11. The phase loss detection device of claim 1 , further comprising:
a first diode (D 4 ) connected in parallel with the first optocoupler input diode at an opposition direction;
a second diode (D 5 ) connected in parallel with the second optocoupler input diode at an opposition direction; and
a third diode (D 6 ) connected in parallel with the second optocoupler input diode at an opposition direction.

12. A compressor, comprising:
a compression component configured to compress suctioned gas and discharge the compressed gas;
a motor configured to drive the compression component;
a phase loss detection device according to claim 1 ; and
a protection switch configured to switch on to turn off the motor if the phase loss detection device detects phase loss;
wherein the phase loss detection device recited in claim 1 comprises a signal converting circuit configured to convert a respective voltage signal corresponding to a respective phase of multiphase AC power monitored from the motor; and
a processor configured to receive the voltage signal converted from the signal converting circuit and configured to:
calculate, based on the voltage signal converted, one or more phase angles between voltage signals; and
determine that phase loss occurs if any one or more of the phase angles deviate from a nominal value of a corresponding phase angle of the multiphase AC power by a value higher than a predetermined threshold.

13. The compressor according to claim 12 , wherein the voltage signal is one of a phase voltage and a line voltage of the motor.

14. The compressor according to claim 13 , wherein the compressor is a scroll compressor.

15. The compressor according to claim 14 , wherein the compressor is a fixed-speed scroll compressor.

16. The compressor according to claim 12 , wherein the compressor is a scroll compressor, wherein, the motor is connected to power supply through a contactor K 1 , and wherein the monitoring port is configured to receive the respective voltage signal from a connecting node between the contactor and the motor;
wherein the phase loss detection device further comprises a protection switch, arranged in a power supply line through the contactor, and wherein if phase loss is detected, the protection switch is configured to be “on” in order to enable the contactor to disconnect power from the power supply to the motor.

17. A phase loss detection method for a motor in a compressor, comprising:
receiving, at a phase loss detection device provided inside a shell of the compressor, a respective voltage signal corresponding to a respective phase of multiphase AC power mon

Assignees

• Danfoss Tianjin Ltd

Inventors

• Ma He
• Yao Li
• Li Guocun
• Zhao Bin
• Shang Zhiwei
• Guo Yongjian

Classifications

• H02P29/0243

  the fault being a broken phase · CPC title

• H02P29/0241

  the fault being an overvoltage · CPC title

• H02M5/458

  using semiconductor devices only · 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

• F04B35/04

  the means being electric · CPC title