過去傳統定頻空調機比較，變頻空調機具有高效率、省電和溫度控制性能等優點。近年來由於變頻器價格的下降，造成變頻空調機的崛起。藉由變頻壓縮機和膨脹閥作為致動器，選取適當的控制參數控制，可有效地改善空調機的運作和性能。

但由於硬體上的限制，變頻空調機在低轉速時壓縮機不能做連續運轉。因此在環境低負載或是使用者房間溫度設定過高，導致房間溫度過冷或是空調機控制不穩定的現象發生。

本論文引入了室內風扇的控制。當壓縮機在最低轉速的運作下，藉由室內風扇的控制改變蒸發器的熱交換的效率進而控制房間溫度。利用風扇切換控制的同時也能降低房間濕度，能改善壓縮機在低轉速下運作時房間濕度偏高的問題。

[1] Jin-Long Lin, Identification and Control of Signal and Multi-Evaporator Air-Conditioning Systems,Nation Tsing-Hua University,(2008)P32-P48

[2] RAJAT SHAH , DYNAMIC MODELING AND CONTROL OF SIGNAL AND MULTI-EVAPORATOR SUBCRITICAL VAPOR COMPRESSION SYSTEMS (1999)

[3] X. -D. He, S. Liu, H. H. Asada, Modeling of vapor compression cycles for multivariable feedback control of HVAC systems, Transaction of the ASME: Journal of Dynamics

[4] Jin-Long Lin and T.-J. Yeh, Modeling Identification and Control of Air-Conditioning Systems, International Journal of Refrigeration 30 (2007) 209-220.

[5] M. Hattori, et. al., Automotive Refrigeration System Controller with a Simple Precompensator, Proceedings of the 29th Conference on Decision and Control, Honolulu, Hawaii, December 1990, pp. 1590~1591

[6] X.-D He, S. Liu, H. H. Asada, and Hiroyuki Itoh, Multivariable Control of Vapor Compression Systems, HVAC&R Research 4(3) (1998) 205-230.

[7] T. Cheng, X.-D. He and H. H. Asada, Nonlinear Observer Design for Two-Phase Flow Heat Exchangers of Air Conditioning Systems, Proceeding of the American Control Conference, USA, 2004, p. 1534-1539.

[8] T. Cheng, X.-D. He, H. H. Asada and S. Kasahara, Heat Exchanger Dynamic Observer Design, ASHRAE Transactions 111 (2005) 328-335.

[9] T.-J. Yeh, Yun-Jih Chen, Wei-Yang Hwang, Jin-Long Lin, Incorporating fan control into air-conditioning systems to improve energy3 efficiency and transient response (2008)

[10] Qi Qi, Shiming Deng, Multivariable control-oriented modeling of a directexpansion (DX) air conditioning (A/C) system

[11] Xiangguo Xu, Shiming Deng, Mingyin Chan A new control algorithm for direct expansion air conditioning systems for improved indoor humidity control and energy efficiency

[12] Luca Zaccarian, Andrew R. Teel, A common franwork for anti-Windup, bumpless transfer and reliable designs, Automaica 38(2002) 1735-1744

[13] Rolf Johansson, System Modeling and Identification, Prentice-Hall International edition, 1993.

[14] J. Howard, Beard, J.Taylor and C. Bolton, Simplified Analytical Modeling of an Air Conditioner with a Positive Displacement Compressor, Proceedings of the 31st IECEC, Vol. 3, pp.2009-2014, August1996.

[15] O. H., S. Torkel Glad, Resolving Actuator Redundancy-Optimal Control vs. Control Allocation., Automatica 41 (2005) 137-144.

[16] 呂宗祐，變頻式空調機之系統鑑別與最佳效率控制，國立清華大學碩士論文。