直线冰箱压缩机活塞位移的自传感技术研究

Study on Self-Sensing Technique of Linear Refrigerator Compressor's Piston Displacement

通过对直线冰箱压缩机的动磁直线电机的等效电路进行分析,建立了活塞位移自传感器的数学模型,得出了压缩机活塞位移的检测及控制方式.为了研究自传感器的性能,设计了一套基于虚拟仪器的活塞位移测控系统,分别对变电压驱动和变可控硅的导通时间驱动方式下的自传感器特性进行了实验研究.实验研究结果表明,利用直线电机作为位移传感器的方法是行之有效的,在活塞行程范围内,变电压和变导通时间驱动方式下的稳态误差分别小于4.4%和7.3%,在上死点附近,最大稳态误差分别为1%和3%,完全可以满足直线冰箱压缩机的控制要求.

A mathematic model of a self-sensor was established by analyzing the moving-magnet linear motor of a linear refrigerator compressor, and measurement and control methods of piston displacement were achieved. For studying the performance of a self-sensor in the driving mode of variable-voltage control and variable time of flow control, a piston displacement measurement and control software based on LabVIEW （version 7.0） was designed, and the experimental study was carried out. The results show that using the linear motor as a self-sensor is effective. Its steady- state error is smaller than 4.4% in variable-voltage control and 7. 3% in variable time of flow control in the range of piston stroke, and its maximum steady-state error is 1% in variablevoltage control and 3 % in variable time of flow control near the top clearance distance. The selfsensor can be applied in the linear refrigerator compressor satisfactorily.