Parameter Identifiation Of Variable-frequency Air Conditioning Compressor

With the widespread use of air conditioning, as well as the update ofconsumers’ ideas, demand for air conditioning is no longer merely limited torefrigeration or heat. Faced with the global energy crisis, energy conservation,which is publicly concerned on, has been the main focus of marketing competitionin the field of air conditioning. Therefore, variable-frequency air conditioners withsome obvious characteristics (e.g. energy conservation, comfort) will graduallyoccupy the entire market of air conditioning. In the production and employment ofvariable-frequency air conditionings, the inaccuracy parameters of compressormotor will result in the worse control performance, even the poorer operationcondition of the system, the lower efficiency and the comfort.According to thepresent situation, this paper employs the parameter identification of thevariable-frequency air conditioning compressor to optimize controlling parameterand ensure the motor running in a well effect. It plays an important role inincreasing the overall efficiency, saving energy, and improving the comfort of theenvironment.The variable-frequency air conditioning compressor system built in this paperchooses IRMCF312developed (by IR as the main control chip) and adopts asensorless vector control algorithm. Based on the analysis of PMSM’s structure andcompressor’s special load environment, the mathematic model is built up based ontheir relative characteristics, also the compressor’s vector control simulation modelis built on the basis of the vector control’s principle in MATLAB/Simulink as well.This paper does some theoretical researches on the double-closed loop vectorcontrol system in depth. Based on this steady system and the actual conditions ofthe project, off-line identification technique is chosen to put forward the eachcorresponding parameters’ recognition proposal and design the relevant calculationmodel in IMotion to make the identification experiments in this paper.This paper adopts a digital PFC technique and a sensorless vector controltechnique in the air conditioning compressor control system. Using this system, atesting system with off-line identification function is developed. Based on that, theidentification proposals have been practiced on the test platform. Identificationresults are mainly matched with the prior-period measurement ones and the error iswithin the bounds. It is proved that this system could accurately identify the motorelectric parameters. The application of the identified parameters has been carriedout to preliminary optimization of the control system. Finally, combined with thereal requirements, a proposal on seperation over10compressors used in Meidi air conditionings on the market has been present on the basis of the off-lineidentification theory.