Conference article

Superheat control has influence on the coefficient of performance (COP); the stability and the compressor endurance of a vapor compression cycle. In an increasing number of applications electronic expansion valves are used. This leads to more complex control tasks. It raises the question if simulation models can be used for feedforward control to fulfill this function. For building a feedforward control structure a simulation model needs to be inverted. In this paper a submodel of a refrigeration cycle; consisting of models for expansion valve and evaporator; is inverted. The resulting controller is tested in a model-in-the-loop environment and applied on an automotive refrigeration cycle. The advantage of a dynamic inverse model in contrast to a static one is pointed out. Also the results are compared to a standard PI controller.

Inverse models; superheat control; vapor compression cycles; feedforward control