Dynamic modeling and model order reduction for vapor compression cycle
A dynamic simulation model of vapor compression cycles is built using the lumped parameter, moving boundary approach. A linearized version of the model suitable for dynamic analysis and controller design is proposed using a Taylor series expansion method, where 2nd order and higher order terms are omitted. Analysis indicates that the linearized model indicates that the system exhibits multiple time-scale behavior and that model reduction is appropriate. For the purpose of control, a model order reduction method, time-scale residualization (TSR), is presented based on the Schur decomposition and singular perturbation technique. Comparing with the other reduction models, the TSR model not only removes the multiple-time scale behavior of the system, but also preserves the DC-gain and the low-medium frequency properties of the system. This reduction model is appropriate for the design of the advance controller.