Motor drive device, refrigeration cycle apparatus, and refrigeration cycle system

A refrigeration cycle system comprising:

• a refrigerant circuit including a compressor in which a motor is provided;
• a power converter including an inverter configured to supply power to the motor;
• and
• a controller configured to perform a feedback control of the motor through the inverter, based on a motor current that is a current flowing in the motor, and calculate power or a work rate of the motor as an index value for use in determining whether an abnormality occurs in the motor or not based on the motor current and a control parameter used in the feedback control,
• wherein
• the controller includes a filter configured to perform a filtering process to extract an abnormal component by removing a component in a normal operating state from the calculated index value, and the controller is configured to conduct a diagnosis of the motor regarding an abnormality or degradation thereof based on the abnormal component of the index value, and
• the filter includes
• a low-pass filter configured to remove from the index value, a harmonic component based on a fundamental wave corresponding to a rotational frequency in a normal operating state of the motor, and
• a high-pass filter configured to remove from the index value, a low frequency component in the normal operating state of the motor.