Dynamic flux weakening for a single phase linear compressor

A linear compressor defining an axial direction and a vertical direction, the linear compressor for an appliance comprising:

• a cylindrical casing defining a compressor chamber;
• a piston positioned within the compressor chamber and being movable along the axial direction;
• a motor operably coupled to the piston;
• and
• a controller configured to control the motor, the controller configured to perform operations for controlling the motor, the operations comprising:
• receiving a d-axis current error signal, a q-axis current error signal, and a DC current error signal;
• determining a DC voltage component signal based on the DC current error signal, the DC voltage component signal being limited by a first voltage threshold;
• then determining a d-axis voltage component signal based, at least in part, on the q-axis current error signal, the d-axis voltage component signal being limited by a second voltage threshold that is different than the first voltage threshold;
• then determining a q-axis voltage component signal based, at least in part, on the d-axis current error signal, the q-axis voltage component signal being limited by a third voltage threshold that is less than the second voltage threshold;
• and
• controlling a motor of the linear compressor using a single-phase vector-like control scheme based, at least in part, on the DC voltage component signal, the d-axis voltage component signal and the q-axis voltage component signal.

An appliance, comprising:

• a cabinet defining an internal chamber;
• a door mounted to the cabinet to provide selective access to the internal chamber;
• a linear compressor, the linear compressor having a piston movable in a negative axial direction toward a compressor chamber and a positive axial direction away from the compressor chamber;
• a motor operably coupled to the piston;
• an inverter configured to supply a variable frequency waveform to the motor;
• and
• a controller configured to control the motor, the controller configured to perform operations for controlling the motor, the operations comprising:
• receiving a d-axis current error signal, a q-axis current error signal, and a DC current error signal;
• determining a DC voltage component signal based on the DC current error signal, the DC voltage component signal being limited by a first voltage threshold;
• then determining a d-axis voltage component signal based, at least in part, on the q-axis current error signal, the d-axis voltage component signal being limited by a second voltage threshold that is different than the first voltage threshold;
• then determining a q-axis voltage component signal based, at least in part, on the d-axis current error signal, the q-axis voltage component signal being limited by a third voltage threshold that is less than the second voltage threshold;
• and
• controlling a motor of the linear compressor using a single-phase vector-like control scheme based, at least in part, on the DC voltage component signal, the d-axis voltage component signal and the q-axis voltage component signal.