A Fast and Accurate Loss Model of Converter-Fed Induction Motor in Central Air-Conditioning System

In the traditional optimization model of central air-conditioner, the loss model of converter-fed motor is very rough, resulting in a large amount of energy waste. In this paper, a new energy loss model of central air-conditioning system from power to client is proposed. In the establishment of the loss model, the characteristics of pump load and variable frequency speed regulation are fully considered, and the electromagnetic variables which are difficult to be collected are replaced by the motor speed which can be directly calculated, so that the motor loss model can be introduced into the optimization model of the central air-conditioning system. A 5.5 kW converter-fed induction motor is tested under different speeds and loads, and the two-dimensional (2-D) loss data were obtained. Then, one-dimensional data were extracted from the measured 2-D data combined with the load characteristics of the pump, and compared with the calculated values of the proposed model in this article. The results show that the proposed loss model is of good accuracy and versatility. Because the proposed analytical model only needs the variable of motor speed to accurately estimate the losses, it can be easily applied to the optimization of central air-conditioning system.