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本文采用TI公司的定点DSP-TMS320F240作为主控制器。对三相50Hz逆变电源采用了瞬时值反馈控制与重复控制相结合的控制方法,利用瞬时值反馈控制抑制基波扰动,提高系统的动态响应过程;利用重复控制抑制非线性负载下的电压波形畸变,提高了系统的静态性能,使逆变电源输出电压波形质量提高。 相似文献
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在分析插值滤波器和均衡器的基础上,讨论了一种自适应插值的定时恢复算法,并进行了仿真.仿真结果表明,这一方法优于拉格朗日插值算法和LMS均衡算法.该算法在完成了对定时误差的插值运算的同时,也消除了衰落引起的码间干扰,性能良好. 相似文献
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智能节水系统中DS12887的数据显示程序设计 总被引:1,自引:0,他引:1
在工业控制、商务以及家居生活等领域中,诸多智能仪表、家用电器需要先获取实时时钟数据然后完成各种控制功能.DS12887是一款功能强大、应用广泛的时钟芯片,文章中介绍了DS1288时钟芯片在智能节水系统中数据采集、数据处理和显示程序的设计方法,思路简洁,运行可靠,保证了智能节水系统红外模式、定时模式等控制功能的实现,并且附加了控制器上的时钟显示功能. 相似文献
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为把人员从大量重复冗余的劳动中解脱出来,针对VHF自动整点播报系统以软件控制硬件进行工作的特点,采用Visual Basic 6.0语言编写控制软件,控制船台机PPT的开关,把以前采用人工方式操作的播报工序改为以微机控制VHF船台机整点或定时自动播发播报内容,大大提高了工作效率。 相似文献
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在分析了传统相似比较法预报船用载货防爆升降机可靠性的缺点后,提出了基于加权相似比较法的船用升降机的可靠性预报方法。其内含已有相似产品的可靠性统计和相关领域内专家和技术人员积累的经验和知识,比传统的相似比较法更能准确和全面地预报新研产品的可靠性。对该方法进行了描述和推理,并且给出了其在船用载货防爆升降机可靠性预报上的应用。 相似文献
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通过介绍OMRON可编程控制器(PLC)在集装箱装卸桥上的具体应用,说明这种速度环PI(Percentage Integration)闭环控制的PLC软件实现的关键技术,同样适用于一般中小型控制系统,并给出了PLC的定时中断实现PI控制的控制算法流程图. 相似文献
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根据SVPWM和载波PWM的内在关系,提出了一种三相逆变器统一SVPWM快速算法.该算法直接利用三相参考电压瞬时值计算PWM信号的开关状态切换时间,不需进行坐标变换、三角函数运算、扇区判断和有效矢量作用时间的计算,因此更易于各种SVPWM方法的数字化实现.实验结果证明了统一SVPWM快速算法的正确有效性.最后,对各种SVPWM方法的电压谐波特性进行对比分析的结果表明当调制比较大时,从谐波特性和开关损耗两方面综合考虑不连续SVPWM的性能较好. 相似文献
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In the previous paper, one of the authors proposed a new time-domain nonlinear strip method for a rigid body, in which hydrodynamic
forces are evaluated by a convolution integral with the memory function computed for the instantaneous submerged part of the
transverse sections, and the Froude–Krylov and hydrostatic forces are evaluated on the instantaneous wetted hull surface.
In this paper, first, that nonlinear strip method is extended for an elastic body using a method of superposition of elastic
mode functions, which enabled us to investigate whipping phenomena due to impulsive large waves. Second, the influence of
different approximations of the pressure above the still-water surface is investigated, and then the results calculated by
the proposed nonlinear strip method are compared with the experimental ones. Third, whipping phenomena observed for an elastic
body at higher Froude numbers are studied through a comparison between computed and measured results. Higher-frequency vibrations
in the vertical bending moment due to slamming are discussed. Furthermore, the wave load due to green water on deck is calculated
by introducing a practical model, and the effects of the green water on responses of both rigid and elastic bodies are investigated. 相似文献
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基于非线性理论的船舶结构稳定性研究 总被引:1,自引:0,他引:1
本文以结构的线性分析为基础,对船舶结构的线性稳定性分析方法进行了改进。同时,采用基于特征值分析的线性稳定性分析方法得到了船舶结构的临界载荷,从该载荷值可以预测出实际结构临界载荷的上限并能较好地反映船舶结构线性性能对其稳定性的影响,据此得出船舶结构的失稳位形。在非线性稳定性分析中,采用NEWTON—ROPHSON方法及弧长法求解考虑非线性时船舶结构的临界载荷,并详细讨论了结构缺陷对稳定性的影响,提出考虑结构缺陷时船舶结构稳定性计算方法。通过不同类型的算例进行分析比较,总结出船舶结构边界条件、几何缺陷变化与船舶结构稳定性之间关系,验证了本文稳定性分析方法的正确性、有效性及对现役散货船船体结构的适用性。 相似文献
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Timothy Lilienthal Akihiko Matsuda Giles Thomas 《Journal of Marine Science and Technology》2007,12(2):111-118
This article presents work based on the development of a performance-based stability assessment method. It describes a numerical
method used to determine the survival limit for a dynamic intact stability assessment procedure. The numerical method utilises
a time-domain vessel motion program to assess the limit for a range of vertical centres of gravity (KG). The appropriateness
of the numerical predictions was examined through comparison with model experiment results. Free-running model tests were
conducted in regular following waves at discrete KGs. A comparison between the survival limits determined through the numerical
and experimental methods is presented. The current International Maritime Organisation (IMO) stability criteria are also evaluated
against the numerical and experimental dynamic performance-based stability assessment methods. 相似文献
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This paper examines the influence of stability characteristics on roll motion in the main parametric resonance region. For this purpose, parametrically exited roll motion was modeled as a single degree of freedom system considering heave and pitch effects by means of time varying restoring moment. In addition, restoring moment variations in waves with respect to time and instantaneous roll angle was modeled analytically using the restoring moment curves for the wave crest and wave trough conditions. Roll responses were evaluated in frequency domain by solving the model with an averaging method. Notable correlation between the stability of roll responses and moment curves were observed. The results revealed that, the ratio of metacentric height (GM)between the wave trough and wave crest affects the stability of the trivial solution. Furthermore, the shape of the restoring moment curves in wave trough and wave crest conditions affects the stability of the non-trivial solution or, in other words, the pitchfork bifurcations. 相似文献
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[Objectives]In order to improve the fault diagnosis level of marine power systems, this paper studies the real-time fault diagnosis of a marine supercharged boiler based on a convolutional neural network (CNN).[Methods]First, the simulation program of the marine supercharged boiler is developed based on the GSE platform, and the simulation fault data is obtained. The fault diagnosis model of the boiler is then established using the CNN method. Next, through the change trends of temperature, flow and other parameters, combined with a priori knowledge and the machine learning method, fault identification is carried out. Lastly, the performance of the method is evaluated against criteria such as confusion matrix and accuracy. [Results]According to the comparison results between the feature extracted dataset and the original dataset, the stability of the model output results and the generalization ability of the model are optimized and improved, with an overall fault classification accuracy reaching 99.53%.[Conclusion]The results of this study can provide valuable references for the intelligent monitoring of marine power systems. © 2022 Chinese Medical Journals Publishing House Co.Ltd. All rights reserved. 相似文献
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为了定量确定整流发电机突加负载时的瞬时电压变化与储能补偿功率之间的关系,提出了一种基于负载等效和曲线拟合的瞬时电压计算方法。该方法通过将整流发电机直流侧的突加负载折算到交流侧,并利用整流桥的电压特性,分别给出了空载突加和带载突加时的瞬时电压表达式;然后,将储能装置的投入等效为负电阻的形式进行功率补偿,通过计算得到瞬时电压与补偿功率之间的关系;最后,根据PSCAD仿真结果对理论计算进行曲线拟合,得到调整后的瞬时电压与补偿功率之间的关系,为下一步研究储能装置的优化配置提供了理论依据。 相似文献