Switching input controller for a food storage room

• Published in: Control engineering practice Vol. 18; no. 5; pp. 507 - 514
• Main Authors: van Mourik, S., Zwart, H., Keesman, K.J.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.05.2010; Elsevier
• Subjects: Agronomy. Soil science and plant productions; Applied sciences; Approximation; bagged potatoes; Biological and medical sciences; bulk-storage; climate control; cold-storage; Computer science; control theory; systems; Control system synthesis; Control systems; Control theory. Systems; Design engineering; distributed process systems; Dynamics; Exact sciences and technology; Exact solutions; Food processing; Foods; foodstuffs; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Harvesting. Postharvest. Storage; mass-transfer; Mathematical analysis; Model reduction; Modelling and identification; Open loop control systems; simulation; Switching; Switching times; transport phenomena; Vegetative propagation. Sowing and planting. Harvesting; Model reduction; Food processing; Open loop control systems; Switching times; Air conditioning; Cooling; Feedback regulation; Control synthesis; Time scale; Experimental study; Linear control; Modeling; Partial differential equation; Open feedback; Engineering design; Function decomposition; Food industry; System reduction; Open loop; Switching time; Reduced order systems; Transfer function; Padé approximation
• ISSN: 0967-0661; 1873-6939
• DOI: 10.1016/j.conengprac.2010.01.009

The temperature dynamics inside a bulk storage room for food products is modeled by a set of partial differential equations, and validated against experimental data. The product temperature is controlled by a cooling installation that is switched on and off on a regular basis. An approximate model is obtained after a timescale decomposition and transfer function (Padé) approximations. On the basis of this approximate model an open loop control problem is formulated and solved analytically. In addition to this, an analytic expression for the time that is needed to cool down the bulk is also derived. The approximate model is suitable for linear feedback controller design and allows a rigorous parameter analysis.