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Operating temperature of proton exchange membrane fuel ceil stack should be controlled within a special range. The input-output data and operating experiences were used to establish a PEMFC stack model and operating temperature control system. A nonlinear predictive control algorithm based on fuzzy model was presented for a family of complex system with severe nonlinearity such as PEMFC. Based on the obtained fuzzy model, a discrete optimization of the control action was carried out according to the principle of Branch and Bound method. The test results demonstrate the effectiveness and advantage of this approach. 相似文献
904.
小波分析在信号消噪中的应用研究 总被引:1,自引:0,他引:1
小波分析具有在频率域的多分辨能力,已广泛用于信号和图像的消噪中。在引入小波阈值去噪方法的基础上,提出了一种新的阈值函数。经过信号仿真验证,这种新的阈值函数取得了较好的消噪效果,克服了采用传统的软、硬阈值函数去噪的不足。 相似文献
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Fish are able to make good use of vortices. In a complex flow field, many fish continue to maintain both efficient cruising
and maneuverability. Traditional man-made propulsion systems perform poorly in complex flow fields. With fish-like propulsion
systems, it is important to pay more attention to complex flow fields. In this paper, the influence of vortices on the hydrodynamic
performance of 2-D flapping-foils was investigated. The flapping-foil heaved and pitched under the influence of inflow vortices
generated by an oscillating D-section cylinder. A numerical simulation was run based the finite volume method, using the computational
fluid dynamics (CFD) software FLUENT with Reynolds-averaged Navier-Stokes (RANS) equations applied. In addition, dynamic mesh
technology and post processing systems were also fully used. The calculations showed four modes of interaction. The hydrodynamic
performance of flapping-foils was analyzed and the results compared with experimental data. This validated the numerical simulation,
confirming that flapping-foils can increase efficiency by absorbing energy from inflow vortices. 相似文献
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