Feedforward control of capacity and superheat for a variable speed refrigeration system

Li, Hua; Jeong, Seok–Kwon; You, Sam–Sang

doi:10.1016/j.applthermaleng.2008.05.022

Cited by 56 publications

(14 citation statements)

References 6 publications

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“…The superheat temperature, T sh , is a function of both states given by (3). By estimating the length of two phase flow, l, with an observer (is presented later), the superheat temperature can be determined.…”

Section: Control Designmentioning

confidence: 99%

“…However, this assumption is valid for the steady state case. In [3], [4], [5], linear models of the superheat is considered(i.e. between the opening degree of the expansion 2014 IEEE International Conference on Systems, Man, and Cybernetics October 5-8, 2014, San Diego, CA, USA 978-1-4799-3840-7/14/$31.00 ©2014 IEEE valve and the superheat temperature), and different types of linear controller is designed.…”

Section: Introductionmentioning

confidence: 99%

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Adaptive super twisting sliding mode control of a HVAC system

Kianfar

Saif

Izadi‐Zamanabadi

2014

2014 IEEE International Conference on Systems, Man, and Cybernetics (SMC)

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In this paper an adaptive super twisting sliding mode cascaded control strategy to control superheat temperature of an evaporator of Heating Ventilation Air Conditioning Systems(HVAC) is presented. Two internal loop and external loop of the cascaded controller are designed using sliding mode by utilizing feedback linearization method. By controlling superheat temperature, T sh , in the external loop, and evaporating temperature of refrigerant, T e , in the internal loop, a better performance with robustness against parameter uncertainty is achieved. The value of superheat temperature is determined by using the estimated value of length of two phase flow of the refrigerant inside the evaporator. The performance of the proposed control strategy against disturbance and parameter uncertainties is illustrated through simulation in MATLAB/Simulink environment. It is shown that in comparison with super-twisting method, the proposed adaptive super twisting method improves the performance of system by reduction of undesirable chattering in the response of system.

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Section: Control Designmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Adaptive super twisting sliding mode control of a HVAC system

Kianfar

Saif

Izadi‐Zamanabadi

2014

2014 IEEE International Conference on Systems, Man, and Cybernetics (SMC)

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“…(1)(2)(3)(4)(5)(6) 정밀 공작기계용 냉각기의 대표적인 제어법으로 는 핫가스 바이패스(Hot-gas Bypass; HB) 제어와 압축기 가변속(Compressor Variable Speed; CVS) 제어가 일반적이다. (2)(3)(4)(5)(6)(7)(8)(9)(10) HB 제어 방식은 제어 구조 가 간단하면서도 제어 정도가 높은 제어법이다. (1)(2)(3) 하지만 부분 부하시에도 압축기가 정속 운전되므로 에너지 절약은 어렵다.…”

Section: 서 론unclassified

Optimum Controller Design of a Water Cooler for Machine Tools Based on the State Space Model

Jeong

Kim²

2011

Korean Journal of Air-Conditioning and Refrigeration Engineerin

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Typical temperature control methods of a cooler for machine tools are hot-gas bypass and compressor variable speed control. The hot-gas bypass system has been widely used to control the cooler temperature in many general industrial fields. On the contrary, the compressor variable speed control is focused on special fields such as aerospace and high precision machine tools which need high precision control. The variable speed control system usually has two control variables such as target temperature and superheat. In other words, the variable speed control system is basically multi-input multi-output(MIMO) system. In spite of MIMO system, the proportional integral derivative(PID) feedback control methodology that based on single-input single-output (SISO) system is generally used for designing the variable speed control system. Therefore, it is inevitable to describe transfer functions for dynamic behaviors of every controlled variables and decide the PID gains with tremendous iteration process. Moreover, the designed PID gains do not provide optimum system performances. To solve these problems, high performance controller design method based on a state space model is suggested in this paper. An optimum controller is designed to minimize both control errors and energy inputs. This method was more simple to describe dynamic behaviors and easier to design the cooler controller which is MIMO system.

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“…The VSRS is a multi-input multi-output (MIMO) system that has obviously nonlinear thermodynamic coupling characteristics [1] .The conventional control schemes in VSRS are primarily focused on two control variables, which are the degree of superheat and the refrigeration capacity [2] . Reference [3] proposed an independent control method for the refrigeration system based on general PI control law. Experimental results showed that the independent control scheme can guarantee not only precise control performance but also high COP for the VSRS.…”

Section: Introductionmentioning

confidence: 99%

Auto Disturbance Rejection Control for a Variable Speed Refrigeration System

Li¹,

et al. 2013

2013 5th International Conference on Intelligent Human-Machine Systems and Cybernetics

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For the problem of coupling in the variable speed refrigeration system, this paper proposes a dynamic feedforward decoupling control method based on active disturbance rejection control (ADRC). Influence of the compressor frequency was regarded as disturbance of superheat control system, the variable speed compressor and electronic expansion valve ADRC controllers were designed. Comparison between the ADRC temperature control and traditional PI temperature control was made. Compared with PI control, the ADRC control is more stable and accurate in regulating chamber temperature although its speed is slightly slow. Simulation result shows that the overshoot of the superheat declines from 22.7% to 5.15% when the influence of the variation of the compressor frequency is compensated with decoupling ADRC control.

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Feedforward control of capacity and superheat for a variable speed refrigeration system

Cited by 56 publications

References 6 publications

Adaptive super twisting sliding mode control of a HVAC system

Adaptive super twisting sliding mode control of a HVAC system

Optimum Controller Design of a Water Cooler for Machine Tools Based on the State Space Model

Auto Disturbance Rejection Control for a Variable Speed Refrigeration System

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