Heat pump device, heat pump system, and method for controlling three-phase inverter

A heat pump system comprising:

• a heat pump device including a refrigerant circuit in which a compressor that compresses a refrigerant, a first heat exchanger, an expansion mechanism, and a second heat exchanger are sequentially connected by piping;
• and
• a fluid utilization device that utilizes fluid heat-exchanged with the refrigerant by the first heat exchanger connected to the refrigerant circuit,
• wherein the heat pump device further includes:
• a motor that actuates the compressor;
• an inverter that applies a predetermined voltage to the motor;
• and
• an inverter controller that controls the inverter, and
• wherein the inverter controller includes:
• a phase switching unit that switches between a phase θp and a phase θn different from the phase θp substantially by 180 degrees, and outputs one of them as a phase of a voltage command value of the inverter in synchronization with a reference signal having a frequency higher than an operation frequency at the time of a compression operation of the motor;
• an amplitude output unit that outputs an amplitude of the voltage command value;
• a voltage-command generator that generates and outputs the voltage command value based on the phase outputted by the phase switching unit and the output amplitude of the amplitude output unit;
• a voltage-command calculator that corrects the voltage command value and outputs the corrected voltage command value;
• and
• a drive-signal generator that generates a drive signal of the inverter based on the output of the voltage-command calculator.

A method for controlling an inverter in a heat pump device including:

• a compressor that compresses a refrigerant;
• a motor that actuates the compressor;
• and
• an inverter that applies a predetermined voltage to the motor,
• the method comprising:
• a phase switching step of switching between a phase θp and a phase θn different from the phase θp substantially by 180 degrees, and outputting one of them as a phase of a voltage command value of the inverter in synchronization with a reference signal having a frequency higher than an operation frequency at the time of a compression operation of the motor;
• an amplitude outputting step of outputting an amplitude of the voltage command value;
• a voltage command generating step of generating and outputting the voltage command value based on the phase outputted at the phase switching step and the output amplitude of the amplitude outputting step;
• a voltage-command correcting step of correcting the voltage command value and outputting the corrected voltage command value;
• and
• a drive-signal generating step of generating a drive signal of the inverter based on the output of the voltage-command correcting step.