Control Structure Selection for Vapor Compression Refrigeration Cycle - Intelligent Computing for Sustainable Energy and Environment - page 477

Control Structure Selection
for Vapor Compression Refrigeration Cycle
Xiaohong Yin , Wenjian Cai, Shaoyuan Li, and Xudong Ding
Department of Automation, Shanghai Jiao Tong University, Shanghai 200240,
P.R. China
School of Electrical and Electronic Engineering, Nanyang Technological University,
Singapore 639798
School of Information and Electrical Engineering, Shandong Jianzhu University, Jinan
250101, China
{ yxh1985,syli } @sjtu.edu.cn , { ewjcai,XDDING } @ntu.edu.sg
Abstract. A control structure selection criterion which can be used to
evaluate the control performance of different control structures for the
vapor compression refrigeration cycle is proposed in this paper. The cal-
culation results of the proposed criterion based on the different reduction
models are utilized to determine the optimized control model structure.
The effectiveness of the criterion is verified by the control effects of the
model predictive control (MPC) controllers which are designed based
on different model structures. The response of the different controllers
applied on the actual vapor compression refrigeration system indicate
that the best model structure is in consistent with the one obtained by
the proposed structure selection criterion which is a trade-off between
computation complexity and control performance.
Keywords: Dynamic modeling, Model reduction, Approximation, Mul-
tiple time-scale system, Singular perturbation.
1 Introduction
The ever-increasing demand for accurate mathematical modeling for simulation
and controller design leads to models of high complexity, arising from high-order
and/or complex nonlinearities. However, complex, nonlinear and multi-variable
models, for instance in the heating, ventilating, and air-conditioning (HVAC)
system, present big challenges for the controller design. In order to make a trade-
off between the modeling accuracy and the convenience in controller design,
control structure selection plays an increasingly important role over the last
two decades[1]. Vapor compression refrigeration cycle system is an important
and necessary part of HVAC system, which is composed of primary components,
such as compressor, condenser, expansion valve, and evaporator. The system is a
high dimensional system that has obviously nonlinear thermodynamic coupling
characteristics and time-varying dynamics characteristics. As a result, direct