Research On Load Modeling And Power Design Of Dielectric Barrier Discharge For NO Transformation

In recent years,with the environmental problems more and more serious,nitric oxide pollution control technology has been widespread concern.And atmospheric pressure dielectric barrier discharge low temperature plasma oxidation conversion method has been widely concerned,because of its high conversion efficiency,simple equipment,easy to maintain and so on.The voltage source resonant converter is the key link in the atmospheric pressure dielectric barrier discharge system.However,the commonly used load equivalent model is still deficient.The influence of the power supply parameters on the conversion efficiency of NO is not completely understood,which limits the design,optimization and engineering application of the resonant converter.Therefore,this dissertation starts with the equivalent model of dielectric barrier discharge load,and conducts research on the establishment of load equivalent model,the extraction of load equivalent parameters,the influence of transformer parasitic parameters on power supply performance and the optimization of power supply performance.First of all,this paper established a dielectric barrier discharge segment model.Based on the detailed analysis of the equivalent mechanism of traditional model,according to the influence of surface charge accumulation on the electric field inside the load,the dielectric equivalent capacitance of the discharge phase is split and a piecewise equivalent model is established.The experimental verification shows that the segmentation model can describe the state transition of dielectric barrier discharge more accurately.Secondly,aiming at the characteristics that the load equivalent model parameters change nonlinearly with the working conditions,a neural network model based on genetic algorithm optimization is proposed in this paper,which can be used to extract parameters of load equivalent model.Experiments show that the proposed model can accurately extract the load parameters in the global condition,which can shorten the power supply design cycle and improve the design accuracy of the power supply under different operating conditions.In the meantime,in order to improve the efficiency of data processing,this paper presents a numerical calculation method of dielectric barrier discharge power based on the Lissajous graph method,and gives the concrete realization process.The experimental results show that the numerical calculation method is in good agreement with the manual calculation and can be used for large-scale experimental data analysis and processing.Then,based on the segmented load model,this paper deduces the state trajectory and key parameters with a segment load model,and analyzes the influence of the parasitic capacitance and leakage inductance of the transformer on the system performance,and the compensation method of series compensation inductor on the primary side of transformer is given.Based on this,this paper designed and built a 500W power prototype.By comparing simulation waveforms and power experimental waveforms,this paper proves the rationality of theoretical analysis and design.Finally,this paper designs and sets up an experimental platform for NO conversion research.we studied the influence of gas environment,reactor structure and power parameters on NO conversion,and emphasis is given to the power optimization strategy under constant power.The experiment shows that reducing the content of O2 is beneficial to improving the conversion of NO and reducing the amount of NO2 production.Under the appropriate discharge power,the increase of the length of the reaction interval and the reduction of the distance between the electrodes are beneficial to the conversion of NO.Under the same power,the output frequency of the power supply is about 25kHz,which is beneficial to the conversion of NO.At the same power,the lower the discharge time ratio,the higher the NO conversion,but the lower discharge time will increase the current stress of the power switch tube and increase the cost of the power supply.If we want to control the amount of N02 generation and reduce the pressure of subsequent removal link,we should increase the discharge time ratio appropriately,and decrease the output frequency of power properly,but this will cause the decrease of NO conversion rate.