Study on Self-Sensor of Linear Moving Magnet Compressor's Piston Stroke

The mathematic model of the self-sensor was established by analyzing the moving magnet linear motor of linear compressor, and the measurement method of piston stroke was achieved. The piston stroke can be calculated by measuring the voltage and current of the linear motor coil. The self-sensor's circuit parameters were influenced by the parameters of the linear motor. For studying the performance of the self-sensor under the driving modes of variable-voltage control and variable time of flow control, piston stroke measurement and control software based on LabVIEW was designed, and the experimental study was carried out. The results show that using the linear motor as self-sensor is effective. Although the self-sensor has nonlinear problems at end of stroke and the electromagnetic interference, the steady-state error of self-sensor can be reduced by means of the better filter circuit and more accurately correcting the end of the piston stroke. So, this self-sensor can be satisfactorily employed with linear compressor.