| A new type of fresh air system, in which the solar energy technology and phase change thermal storage technology are combined, was studied in this paper. It has a wide application prospect and good social benefits in the field of green energy and energy saving.The simulated equipment was built, which is for the small solar fresh air system. The study of the system model, simulated method and control method is finished. The experimental platform of solar fresh air system is based on this work. The advanced control algorithms were researched for the new type fresh air system, according to the analysis of the operating rules. And the experiments demonstrate the effectiveness of these control algorithms.The main research work and research results are listed as follows:1. The simulated equipment for small solar fresh air system was built. And the validation of the design scheme, together with the controlling experiment of several kinds of operation modes, was performed. On the basis of experimental data and thermodynamic characteristics of the simulating system, the simulation model was built and the validation of this model was performed with the help of fuzzy control experiment.2. The new type of fresh air experimental platform in which the solar energy technology and phase change thermal storage technology are combined was built, according to the characteristics of this kind of platform, such as large quantities of control variables and operation mode, complicated controlling system. In this platform, the phase change thermal storage material was used for energy storage, with thermal energy to be supplied without sunshine. There are 9 types of operating model available in this platform, with research on the controlling of fresh air in many conditions to be performed.3. A large quantity of controlling equipments were designed and finished in the experimental platform, with its characteristics for different kinds of operating modes and different operation stage studied. And the operating character and controlling rule were obtained, including the controlling relation between the fresh air temperatures and controlling voltage of inverter, the controlling voltage range of inverter, the controlling range of the fresh air temperature, the relation between the hot water temperature and the set temperature of fresh air, the system character when switching mode. As a result, the follow-up designation of system controller was well done with the full experimental data and the practical controlling experience.4. With the fresh air system having the characteristics of time-varying parameters, nonlinearity and numerous influence factors, the effective fuzzy control strategy was put forward in the paper, in which different fuzzy control rule was designed according to different operating modes, and the controlling method combining the coarse adjustable controller and fine adjustable controller was designed in the same operation mode. As a result, the response speed was improved, with controlling precision and controlling stability assured. As proved in the experimental result, the application of this kind of controlling strategy can assure the precise controlling of the fresh air temperature.5. With the nerve fuzzy adaptive technology applied in the designation of fuzzy control strategy for solar fresh air system, the Takagi-Sugeno type fuzzy controller was built automatically, based on BP neural network theory and the experimental data. The above method can be used as the effective aided means for the designation of fuzzy control rule for fresh air system, to improve the designing efficiency of the fuzzy controller. The controller, which was realized automatically, is tested on the two modes:solar energy fully for the fresh air mode, phase change thermal storage fully for the fresh air mode, and the experiment shows that it also reaches the required control precision comparing to the fuzzy controller designed manually.6. The control method, combined the PID relay auto-tuning with single neuron adaptive PID control together, was proposed and applied to the solar energy fresh air system. The above method referred to as self-adaption PID control can adjust the parameters of the controller on the basis of initial parameters determined by the relay auto-tuning method. According to experiments for the different set values control of the fresh air temperature and stable control of fresh air temperature during different operation modes conversion, it shows that it satisfy the control precision. |
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