Electric compressor control device, electric compressor, and electric compressor control method

An electric compressor comprising:

• a compressor;
• a motor that drives the compressor;
• a control unit of an inverter that controls the motor;
• a physical quantity calculation unit that calculates a physical quantity that changes according to a workload of the compressor based on one or a plurality of predetermined detection values obtained from the inverter;
• a rotation speed acquisition unit that acquires a rotation speed of the motor;
• a storage unit that stores:
• information representing a first threshold value that changes according to the rotation speed of the motor and defines whether or not the physical quantity is a normal value;
• and
• information representing a second threshold value that changes according to the rotation speed of the motor and defines whether the physical quantity is a slight abnormality or severe abnormality in a case where the physical quantity is not normal;
• and
• a refrigerant abnormality determination unit that determines whether or not there is an abnormality in a refrigerant system by comparing the calculated physical quantity with the first threshold value according to the acquired rotation speed, wherein
• the refrigerant abnormality determination unit determines whether the refrigerant system is in a normality, slight abnormality, or severe abnormality by comparing the calculated physical quantity with the first threshold value and the second threshold value according to the acquired rotation speed, and
• in a case where determination is made to be the severe abnormality, the refrigerant abnormality determination unit determines that operation is not continuable when a time from the determination to be the slight abnormality to the determination to be the severe abnormality is shorter than a first time.

An electric compressor control method which is a control method of an inverter that controls a motor that drives a compressor, the method comprising:

• a step of calculating a physical quantity that changes according to a workload of the compressor based on one or a plurality of predetermined detection values obtained from the inverter;
• a step of acquiring a rotation speed of the motor;
• a step of determining whether or not there is an abnormality in a refrigerant system by comparing the calculated physical quantity with a first threshold value that changes according to the rotation speed of the motor and defines whether or not the physical quantity is a normal value according to the acquired rotation speed;
• and
• a step of determining whether the refrigerant system is in a normality, slight abnormality, or severe abnormality by comparing the calculated physical quantity with the first threshold value and a second threshold value according to the acquired rotation speed, wherein the second threshold value changes according to the rotation speed of the motor and defines whether the physical quantity is a slight abnormality or severe abnormality in a case where the physical quantity is not normal, wherein
• in a case where determination is made to be the severe abnormality, the method further comprises determining that operation is not continuable when a time from the determination to be the slight abnormality to the determination to be the severe abnormality is shorter than a first time.