International Journal of Air-Conditioning and Refrigeration

The Society of Air-Conditioning and Refrigerating Engineers of Korea (대한설비공학회)
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PI Control with the Smith Predictive Controller for a Variable Speed Refrigeration System

  • Hua, Li (Department of Refrigeration and Air-conditioning Engineering, Graduate School, Pukyong National University) ;
  • Choi, Jeong-Pil (Department of Refrigeration and Air-conditioning Engineering, Graduate School, Pukyong National University) ;
  • Jeong, Seok-Kwon (School of Mechanical Engineering, Pukyong National University) ;
  • Yang, Joo-Ho (School of Mechanical Engineering, Pukyong National University) ;
  • Kim, Dong-Gyu (School of Mechanical Engineering, Pukyong National University)
  • Published : 2007.09.30
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Abstract

In this paper, we suggest PI control with the Smith predictive controller to improve transient response of a variable speed refrigeration system (VSRS). As the refrigeration system has long dead time inherently, it is difficult to get fast responses of super-heat and reference temperature. We incorporated the Smith predictive controller into PI to compensate the effect of the long dead time of the system. At first, we introduced the decoupling model of the system to control capacity and superheat simultaneously and independently. Next, we designed the predictive controller of the superheat based on PI control law. Finally, the control performance by the proposed method was investigated through some numerical simulations and experiments. The results of the simulations and experiments showed that the proposed PI control with the predictive controller could obtain acceptable transient behaviour for the system.

Keywords

References

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