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

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.