Heat pump device, and air conditioner, heat pump water heater, refrigerator and freezing machine including heat pump device

A heat pump device comprising:

• a compressor including a compression mechanism that compresses a refrigerant and a motor that drives the compression mechanism;
• a heat exchanger;
• an inverter that applies a predetermined voltage to the motor;
• and
• an inverter control unit that generates a driving signal for driving the inverter, wherein:
• the inverter control unit includes:
• an energization control unit that, during a standby operation of the compressor, carries out energization of the motor by using at least one of a direct current and a frequency and heats a refrigerant in the compressor;
• the energization control unit includes:
• a refrigerant stagnation amount output unit that estimates or detects and outputs a refrigerant stagnation amount to the compressor,
• a heating-amount calculating unit that calculates a heating amount corresponding to the refrigerant stagnation amount, and
• an energization-switching unit that switches, on the basis of a first temperature around the compressor and a second temperature of the compressor itself and the heating amount, between the direct-current energization and the frequency energization;
• and
• the inverter control unit, including the energization control unit, is configured by one of a Central Processing Unit, a Digital Signal Processor, a microcomputer, and an electric circuit element.