Abstract: A variable displacement compressor includes a plate having a variable inclination angle, and a piston engaging the plate. The piston reciprocates within a bore of the compressor in accordance with a rotation of the plate, and the piston has a stroke length which is determined by the inclination angle of the plate. The compressor also includes a sensor positioned adjacent to the piston. The sensor generates an output signal when a predetermined portion of the piston is aligned with the sensor. The compressor also includes a processing unit operationally coupled to the sensor. The processing unit estimates the inclination angle of the plate based on the output signal from the sensor.