Summary

This work proposes a procedure for system identification of refrigeration systems composed of variable capacity compressor (VCC) and electronic expansion valve (EEV) for future application of multivariable control strategies focused in power consumption minimization and coefficient of performance optimization on these kind of systems. To this end, an experimental apparatus comprised by a VCC and an EEV with 1000W of maximum refrigeration capacity was used. A first round of experiments was carried out to generate an initial knowledge of the system. The next step was the system identification in a specifically region of operation using linear MIMO models (Multiple Input - Multiple Output) based on the principle of superposition. A complete state estimator was developed and implemented in the control and acquisition system of the experimental apparatus to validate the linear MIMO models. Consequently, it was designed a proportional controller adjusted by LQR Method (Linear-Quadratic Regulator). This controller was included in the Simulink, a Matlab ® tool to simulate the system in the time domain. Preliminary results for tracking problems are presented and discussed in this work, along with the advantages of control application in refrigeration systems.

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