The frequency response of an evaporator for commercial refrigeration is investigated to develop a control-oriented model which balances simplicity with accuracy. The dynamics of such devices is highly nonlinear; the response curve was experimentally identified around an operating point by recording the output of the system for several sinusoidal input signals. Among the possible linear approximating models, the collected data turn out to be best fitted with a fractional order transfer function. The proposed identification and process model allow for online tuning at different operating points for an efficient control design.

中文翻译：

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制冷蒸发器的分数性质研究

对用于商业制冷的蒸发器的频率响应进行了研究，以开发一种以控制为基础的模型，该模型在简单性和准确性之间取得了平衡。这种设备的动力学是高度非线性的。通过记录几个正弦输入信号的系统输出，通过实验确定响应曲线在工作点附近。在可能的线性近似模型中，事实证明，所收集的数据最适合使用分数阶传递函数。所提出的识别和过程模型允许在不同的操作点进行在线调整，以实现有效的控制设计。