Heat pump device, air conditioner, and refrigerating machine

A heat pump device comprising:

• a compressor including a compression mechanism configured to compress a refrigerant and a motor configured to drive the compression mechanism;
• heat exchangers;
• an inverter configured to apply a desired voltage to the motor;
• and
• an inverter control unit configured to generate PWM signals for driving the inverter,
• wherein
• the inverter control unit includes:
• a heating determining unit configured to determine whether heating of the compressor is necessary and notify a determination result;
• and
• a PWM-signal generating unit configured to shift to, upon receiving the notification indicating that the heating is necessary, a heating operation mode for heating the compressor and, in the heating operation mode, generate the PWM signal to provide, based on a heating time carrier signal having two or more predetermined frequencies, a period in which a reflux current flows, and
• the heating time carrier signal is generated to form a combined cycle in which the predetermined frequencies are arranged in a predetermined order by cyclically switching each of the predetermined frequencies at each one cycle and repeat the switching in the combined period for each combined period, and a combined frequency, which is a frequency corresponding to the combined cycle, is set to a frequency equal to or lower than 20 hertz.

A heat pump device comprising:

• a compressor including a compression mechanism configured to compress a refrigerant and a motor configured to drive the compression mechanism;
• heat exchangers;
• an inverter configured to apply a desired voltage to the motor;
• and
• an inverter control unit configured to generate PWM signals for driving the inverter,
• wherein
• the inverter control unit includes:
• a heating determining unit configured to determine whether heating of the compressor is necessary and notify a determination result;
• and
• a PWM-signal generating unit configured to shift to, upon receiving the notification indicating that the heating is necessary, a heating operation mode for heating the compressor and, in the heating operation mode, generate the PWM signals to provide, based on a heating time carrier signal having two or more predetermined frequencies, a period in which a reflux current flows, and
• the heating time carrier signal is generated by switching the predetermined frequencies in random order.

A heat pump device comprising:

• a compressor including a compression mechanism configured to compress a refrigerant and a motor configured to drive the compression mechanism;
• heat exchangers;
• an inverter configured to apply a desired voltage to the motor;
• and
• an inverter control unit configured to generate PWM signals for driving the inverter,
• wherein
• the inverter control unit includes:
• a heating determining unit configured to determine whether heating of the compressor is necessary and notify a determination result;
• and
• a PWM-signal generating unit configured to shift to, upon receiving the notification indicating that the heating is necessary, a heating operation mode for heating the compressor and, in the heating operation mode, generate the PWM signals to provide, based on a heating time carrier signal having two or more predetermined frequencies, a period in which a reflux current flows, and
• in the heating operation mode, when switching elements configuring the inverter are divided into an upper side switching element group and a lower side switching element group, the heat pump device reduces a first period, which is a period in which all the switching elements of the upper side switching element group are turned on, from an immediately preceding first period by a predetermined time or reduces a second period, which is a period in which all the switching elements in the lower side switching element group are turned on, from an immediately preceding second period by the predetermined time and increases, by a half of the predetermined time, each of periods of other switching states before and after the period reduced by the predetermined time.