A linear compressor and methods of operation, for example, to control a setpoint and vary cooling capacity of the linear compressor, are provided herein. An appliance may include a linear compressor having a reciprocating piston movable in a negative axial direction toward a chamber and positive axial direction away from the chamber. The appliance may further include a motor operatively coupled to the reciprocating piston, the motor having a resting setpoint, an inverter configured to supply a variable frequency waveform to the motor, and a controller configured to control the variable frequency waveform. The controller may be configured to direct a positive DC voltage to the motor to shift the resting setpoint to increase a cooling capacity of the linear compressor.

A method for protection and diagnosis of a linear compression including at least one electronic control. At each work cycle of the linear compressor, the protection method includes detecting a suction time of the linear compressor; detecting a compression time of the linear compressor; and calculating, after detecting a compression time of the linear compressor, a decision parameter equivalent to the difference between the previously detected suction time and the compression time.

A method for protection and diagnosis of a linear compression (2), the linear compressor (2) including at least one electronic control (11), the protection method being configured to perform the following steps at each work cycle of the linear compressor (2): detecting a suction time (t.sub.s) of the linear compressor (2); detecting a compression time (t.sub.c) of the linear compressor; calculating, after the step of detecting a compression time (t.sub.c) of the linear compressor, a decision parameter (T) equivalent to the difference between the previously detected suction time (t.sub.s) and the compression time (t.sub.c).