Performance Analysis of a Standalone Inverter System Under Variable Loading Conditions

2021 ◽  
pp. 11-19
Author(s):  
David Hmingthanmawia ◽  
K. Lalmalsawma ◽  
Samuel Lalngaihawma ◽  
Subir Datta ◽  
Subashish Deb ◽  
...  
Author(s):  
Thokchom Subhaschandra Singh ◽  
Nimo Singh Khundrakpam ◽  
Prerana Nashine ◽  
Tikendra Nath Verma ◽  
Moon Banerjee

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1459
Author(s):  
Penghao Wang ◽  
Hao Liu ◽  
Ming Hou ◽  
Limin Zheng ◽  
Yue Yang ◽  
...  

The major challenges for the commercialization of proton exchange membrane fuel cells (PEMFCs) are durability and cost. Prognostics and health management technology enable appropriate decisions and maintenance measures by estimating the current state of health and predicting the degradation trend, which can help extend the life and reduce the maintenance costs of PEMFCs. This paper proposes an online model-based prognostics method to estimate the degradation trend and the remaining useful life of PEMFCs. A non-linear empirical degradation model is proposed based on an aging test, then three degradation state variables, including degradation degree, degradation speed and degradation acceleration, can be estimated online by the particle filter algorithm to predict the degradation trend and remaining useful life. Moreover, a new health indicator is proposed to replace the actual variable loading conditions with the simulated constant loading conditions. Test results using actual aging data show that the proposed method is suitable for online remaining useful life estimation under variable loading conditions. In addition, the proposed prognostics method, which considers the activation loss and the ohmic loss to be the main factors leading to the voltage degradation of PEMFCs, can predict the degradation trend and remaining useful life at variable degradation accelerations.


Author(s):  
Chin-Pun Teng ◽  
Jorge Angeles

Abstract The problem of structural optimization under variable loading conditions is discussed here. We assume a linearly-elastic structure subject to one single load of constant magnitude but of arbitrary orientation. Moreover, we assume that the structure is discretized by finite elements. The result of this study is an optimality criterion: the eigenvalues of the stiffness matrix of the optimum structure observe a minimum variance. In other words, the optimum structure under variable load must have a stiffness matrix that is as close as possible to isotropy. Furthermore, in order to implement the foregoing criterion, we introduce a novel method of automatic mesh generation, that is based on the concept of penalty functions of nonlinear programming. Finally, we illustrate these concepts by means of the optimization of a triangular lamina of given side lengths, with an elliptical hole centered at its centroid, of a prescribed area, the design parameters being the semiaxes of the ellipse and the orientation of these axes with respect to the edges of the lamina.


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