| Title |
State Equation Modeling and the Optimum Control of a Variable-Speed Refrigeration System |
| Authors |
이단비(Dan-Bi Lee) ; 정석권(Seok-Kwon Jeong) ; 정영미(Young-Mi Jung) |
| DOI |
http://dx.doi.org/10.6110/KJACR.2014.26.12.579 |
| Keywords |
가변속 냉동시스템 ; 최적제어 ; 다입?출력시스템 ; 상태방정식 ; 동일차원 상태관측기 Variable speed refrigeration system ; Optimum control ; Multi-input multi-output system ; State equation ; Full order state observer |
| Abstract |
This paper deals with precise analytical state equation modeling of a variable speed refrigeration system (VSRS) for optimum control in state space. The VSRS is described as multi-input and multi-output (MIMO) system, which has two controlled variables and two control inputs. First, the Navier-Stokes equation and mass flow rate were applied to each component of the basic refrigeration cycle to build a dynamic model. The dynamic model, represented by a differential equation, was transformed into the state equation formula. Next, a full-order state observer was built to estimate all of the state variables to compose an optimum control system. Then, an optimum controller was designed to minimize an evaluation function that has input energy and control error. Finally, simulations and experiments were conducted to verify the validity of the proposed modeling and designed optimum controller to regulate target temperature and superheat in a 1RT oil cooler system. The results show that the proposed method, state equation modeling and optimum control, is efficient to ensure optimal control performance of the VSRS. |