scholarly journals Optimal Rating and Position of Distributed Generators under Variable Loading Conditions using Bacterial Foraging Algorithm

2015 ◽  
Vol 8 (35) ◽  
Author(s):  
J. Belwin Edward ◽  
K. Ravi ◽  
R. Sarjila ◽  
C. Sakthigokulrajan ◽  
Avagaddi Prasad
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.


2012 ◽  
Vol 518 ◽  
pp. 119-126 ◽  
Author(s):  
Fakher Chaari ◽  
Walter Bartelmus ◽  
Radoslaw Zimroz ◽  
Taher Fakhfakh ◽  
Mohamed Haddar

Transmissions including spur gears are widely used in several industrial applications. They are characterized by high efficiency and capability to transmit high torques. A special attention should be made for transmissions running under varying loading conditions which have to be well monitored. The presence of this variability associated with defects that may occur in the transmission will complicate its condition monitoring. The first step to overcome this difficulty is to identify and characterize the dynamic response of the transmission in healthy conditions subjected to variable loading conditions. In this paper, a model based approach is presented in order investigate the influence of the loading shape on the vibration characteristics of the transmission. A dynamic model of a one stage spur gear transmission including a time varying loading conditions is developed. Two cases of loading conditions are considered. A parametric study is achieved and main conclusions are discussed.


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