Prognostic And Control Of Solid Oxide Fuel Cell

As the representative of the third generation of new energy batteries,Solid Oxide Fuel Cell(Solid Oxide Fuel Cell)can realize the direct conversion of chemical energy to electrical energy under high temperature conditions.Hailed as the most promising green environmental protection energy in the century,it has high power generation efficiency,narrow noise distribution area,and few harmful emissions.However,due to the adverse effects of high temperature environment on the internal materials of the system,the SOFC performance degradation happens with the time passing by,which severely shortens the battery life,and becomes a major bottleneck hindering the development of SOFC.If the remaining useful life of the system can be accurately predicted at the initial stage of performance degradation,and effective maintenance measures can be taken in time,services life will be greatly extended.Therefore,the main research contents of this article include:(1)Consider the remaining useful life prediction under the degradation of single cell performance.Firstly,based on the principles of thermodynamics and electrochemical reactions,MATLAB tool is used to build and verify the single cell degradation mechanism model under the premise of meeting the conservation of mass and energy.Then,the single cell voltage degradation data is collected by the model.Finally,an improvement method that combines wavelet decomposition and Echo State Network is proposed to realize the prediction of the remaining useful life of single cell performance degradation under non-stationary data fluctuations.Taking the voltage degradation data under three different load currents as examples,the effectiveness and accuracy of the proposed algorithm are verified.(2)Since the actual industrial field often increases the number of cells to meet larger load requirements,and the degradation speeds of different cell stacks are not same even under the same operating conditions,the coupling between them will also affect the degradation status.Therefore,this paper proposes a life prediction method of SOFC multi-cells system based on the correlation of the cell degradation process.Firstly,a model of the Wiener stochastic process with uncertainty is used to characterize the particularity of the individual cell degradation process,and a residual life probability density model under the degradation of the single cell Wiener process is established.Then,the remaining useful life distribution of the single battery is obtained after the prior knowledge of the unknown parameters of the model obtained by the bootstrap method and the model parameters are updated by the maximum likelihood estimation algorithm under the Byes law.Next,the Copula function is used to describe the correlation between the cells,and the residual life distribution model of the multi-cells system under the correlated degradation process is established.Finally,the likelihood method is used to estimate the correlation coefficient,and the remaining life prediction under the coupled condition of the multi-cells system is realized.Taking the degradation data of the two-cell interconnected system as an example,the rationality and reliability of the proposed method are verified(3)From the perspective of life extension,a relationship between the remaining useful life and the power generation efficiency is studied on the basis of the life prediction results,and a control strategy to delay the degradation of SOFC performance is proposed in this paper.Firstly,the voltage degradation prediction result is used to calculate the performance degradation rate of the SOFC without maintenance.Then,target reference trajectories of different degrees reduction of performance degradation rates are set under the great power generation efficiency.Finally,desired reference trajectories are tracked perfectly by a feedback-iterative learning controller.Taking the degradation data of specific operating conditions of single cells as an example,it is verified that the proposed method can extend the SOFC life to various degrees,and control the loss of power generation efficiency within a reasonable range.