Browse > Article

EEV Superheat Control of a Multi-type Heat Pump by Using Dither Signal  

한도영 (국민대학교 기계ㆍ자동차공학부)
표수환 (국민대학교 기계공학과 대학원)
Publication Information
Korean Journal of Air-Conditioning and Refrigeration Engineering / v.14, no.11, 2002 , pp. 948-953 More about this Journal
Abstract
The electronic expansion valve (EEV) may be used to control the refrigerant flow rate for the multi-type heat pump. Stepping motor driven EEV may precisely control the refrigerant flow rate to meet each internal load requirement. To control the EEV, PI algorithm may be used. But the hysteresis of EEV deteriorates the performance of superheat control. To reduce the performance degradation, the PI algorithm along with the dither signal may be used. The dither signal, with about 10 times higher frequency than the system crossover frequency and about 10 times larger magnitude than the deadband of hysteresis, was selected for the superheat control of EEV. Experimental results showed the improvement of EEV control by adding the dither signal to the PI algorithm.
Keywords
Electronic expansion valve; Hysteresis; Superheat control; Dither signal; PI control algorithm; Crossover frequency;
Citations & Related Records
Times Cited By KSCI : 1  (Citation Analysis)
연도 인용수 순위
1 Wallen, A., 1997, Valve diagnostics and automatic tuning, Proceeding of the American Control Conference, pp. 2930-2934
2 Higuchi, K., 1986, Electronic expansion valve and control, Refrigeration, Vol. 61, pp. 45-52
3 Tassou, S. A. and Al-Nizari, H. O., 1993, Investigation of the effects of thermostatic and electronic expansion valves on the steady-state and transient performance of commercial chillers, Int. J. of Refrigeration, Vol. 16, No. 1, pp. 49-56
4 Hsiao, F. H., 1997, Optimal controller for dithered systems with backlash or hysteresis, J. of Optimization Theory and Applications, Vol. 94, No. 1, pp. 87-113
5 Finn, P. D., 2000, Control and optimization issues associated with algorithm-controlled refrigerant throttling devices, ASHRAE Transactions, Vol. 106, Pt. 1
6 Han, D. and Kim, K., 1998, Design and control of dynamic environmental chamber, Proceedings of the SAREK, pp. 656-661
7 Outtagarts, A, 1997, The transient response of evaporator fed through an electronic expansion valve, Int. J. of Energy Res., Vol. 21, pp. 793-80   DOI   ScienceOn
8 Han, D. and Kwon, H., 1999, Zone temperature control of the multi-type heat pump system, Proceedings of the SAREK, pp. 611-616