Compressor and method for controlling the same

An apparatus comprising:

• a refrigeration cycle, the refrigeration cycle including:
• a compressor, the compressor including:
• a cylinder;
• a discharge unit configured to discharge a refrigerant compressed in the cylinder;
• a piston configured to reciprocate in the cylinder;
• a linear motor configured to provide a driving force to move the piston;
• a sensor configured to detect a motor current of the linear motor;
• and
• a compressor controller configured to:
• detect information related to a load of the apparatus;
• calculate a phase difference between a stroke of the piston and the detected motor current;
• compare the calculated phase difference with a reference phase difference;
• and
• drive the linear motor in correspondence to the detected load based on a result of the comparison between the calculated phase difference and the reference phase difference;
• a condenser;
• and
• an evaporator,
• wherein, if the apparatus includes an apparatus controller, the compressor controller is provided separate and independent from the apparatus controller,
• wherein the compressor controller is configured to drive the linear motor such that a cooling capacity of the compressor is changed according to the result of the comparison between the calculated phase difference and the reference phase difference,
• wherein the compressor controller is configured to decrease the reference phase difference when the linear motor is driven in a second driving mode for more than a second time interval, and
• wherein, in the second driving mode, the linear motor is driven such that the piston is spaced away from the discharge unit to decrease the cooling capacity of the compressor.