Multivariable Identification and Control of a Calorimeter Used for Performance Evaluation of Refrigerant Compressors

Refrigerant compressors are relatively complex products that require a wide variety of tests to be performed for both product development and quality control. Performance tests are an example of such tests and they are typically performed using test rigs with calorimeters. This paper presents the experimental results of the use of a multivariable dead-time compensating structure to control the conditions at the calorimeter inlet and outlet. Besides the control results themselves, the paper presents the identification of the multivariable model used for control purposes, as well as it discusses tuning and implementation of the proposed controller. The closed-loop experimental results are compared to the ones obtained by using PID controllers and they demonstrate the good performance of the implemented controller. As a result, both the test time and the result uncertainties have been reduced. Besides presenting an important contribution from the point of view of industrial application, this study presents experimental results of dead-time compensators, which are generally analyzed just towards simulation.