In this paper a virtual refrigerant charge sensor (VRCS) for a booster refrigeration system with a receiver unit is developed and proposed. The VRCS estimates the liquid charge in the receiver unit by utilizing a combined mass and energy balance equation for mapping the change in the receiver unit’s time constant to the liquid volume in the receiver unit. The time constant for the receiver unit is found by utilizing the commonly available data in an online subspace identification method. The parameters estimated by the online subspace identification method are recast in a linear fractional transformation structure to identify parameter changes due to liquid volume change. Hence, the VRCS functions in a plug and play framework where only the initial refrigerant charge in percentage is required to be known. Results from utilizing the VRCS on experimental data from a charge test conducted on a test setup located at Danfoss A/S are shown, where the VRCS shows an accurate estimation of the liquid charge in the receiver. The results from the VRCS can be employed for: early prediction of low charge in the system, early detection of a too large leakage rate, estimation of the current charge on a daily basis, and estimation of the amount of charge lost.

在本文中，提出并提出了一种用于带有接收器单元的增压制冷系统的虚拟制冷剂充气传感器（VRCS）。VRCS通过利用质量和能量的平衡方程式将接收器单元时间常数的变化映射到接收器单元中的液体体积来估计接收器单元中的液体电荷。通过使用在线子空间识别方法中的常用数据来找到接收器单元的时间常数。通过在线子空间识别方法估计的参数将以线性分数变换结构进行重铸，以识别由于液体体积变化而引起的参数变化。因此，VRCS在即插即用框架中起作用，在该框架中，仅需要知道初始制冷剂填充百分比。显示了利用VRCS在丹佛斯A / S的测试装置上进行的电荷测试获得的实验数据的结果，其中VRCS显示了接收器中液体电荷的准确估算。VRCS的结果可用于：早期预测系统中的低电量，及早检测出过大的泄漏率，每天估算当前电量以及估算电量损失。