垂荡浮子式波能转换装置水动力性能研究

发布时间：2018-05-17 09:24

本文选题：波能转换转置 + 频域分析　；参考：《大连理工大学》2016年硕士论文

【摘要】：随着日益增长的能源需求与日渐枯竭的传统能源之间矛盾不断加剧,人们将眼光转向了蕴含巨大能量的海洋波浪能。虽然相比其他可再生能源,对波浪能的研究和开发起步较晚,但是经过各国研究人员努力,现已提出了多种不同原理的波能转换装置概念,并且部分已经得到了工程上的应用。波浪能利用技术的关键在于波能转换装置WECs (Wave Energy Converters)的设计。本文的研究对象是垂荡浮子式波能转换装置,它以一个做垂荡运动的浮子作为吸收波浪能的载体,采用直接驱动线性发电机驱动发电,实现从波浪能到电能的转换。通过频域分析和时域模拟等研究手段,探索不同控制策略以及浮子形状参数对波能转换装置水动力性能和波能俘获特性的影响。首先采用频域分析方法,考虑直接驱动的垂荡浮子式波能转换装置,建立该装置的频域运动方程,获得该装置的频率响应函数,分别推导了WEC在规则波和不规则波作用下的时间平均波浪吸收能和能量俘获宽度,并详细讨论了四种不同线性PTO(Power-Take-Off)力控制方法对装置波浪能吸收最大化和能量俘获宽度的影响,其中在规则波中采用最优因果控制,在不规则波中采用次优因果控制。其次采用以状态空间模型替代时域运动方程卷积项的方法,建立Matlab Simulink时域仿真模型对装置进行时域模拟,探索不同控制策略下浮子运动特性以及波浪能吸收随时间变化规律。通过和频域结果比对,验证状态空间模型替代方法的准确性,并进一步研究四种线性PTO力控制方法的机理。然后,采用时域仿真模型,研究了非线性闭锁控制方法对装置波浪能吸收的影响,结果表明闭锁控制够在有效控制的基础上提高WEC的速度从而增大波浪吸收能,同时也不会产生无功功率,但是闭锁控制下的能量输出是不连续的,这就需要PTO具有一个短期蓄能的装置,而在直接驱动系统中是难以实现的。为了与实际情况相符,在时域仿真模型中加入止动系统来约束浮子的最大位移,结果表明止动系统能够很好地控制装置的位移幅值,但是当采用复共轭控制时会进一步增大所需的PTO力。最后,在保证经济性和可行性的前提下,采用频域分析方法,考虑使用PTO有效控制作为控制策略,针对不同的浮子形状参数,讨论质量、半径、锥角以及形状等因素对装置水动力性能以及波浪吸收效率的影响,为波能转换装置的选形提供了参考依据。
[Abstract]:With the increasing energy demand and the increasingly depleted traditional energy conflicts, people turn their eyes to the ocean wave energy which contains enormous energy. Compared with other renewable energy sources, the research and development of wave energy started late, but through the efforts of researchers from various countries, the concept of wave energy conversion device with different principles has been put forward, and some of it has been applied in engineering. The key of wave energy utilization is the design of WECs wave Energy converters. The research object of this paper is the wave-energy conversion device of pendulum float, which takes a floating float as the carrier of absorbing wave energy, and uses direct driving linear generator to drive power generation, which realizes the conversion from wave energy to electric energy. By means of frequency domain analysis and time domain simulation, the effects of different control strategies and float shape parameters on the hydrodynamic performance and wave energy capture characteristics of wave-energy conversion device are explored. In this paper, the frequency domain motion equation is established and the frequency response function of the device is obtained by using the frequency domain analysis method and considering the wave energy conversion device of the pendulum float driven directly. The time average wave absorption energy and energy capture width of WEC under regular and irregular waves are derived, and the effects of four different linear PTO Power-Take-Off-Off-force control methods on the maximum wave energy absorption and energy capture width are discussed in detail. Among them, optimal causal control is used in regular waves and suboptimal causal control in irregular waves. Secondly, by replacing the convolution term of time domain motion equation with state space model, the Matlab Simulink time domain simulation model is established to simulate the time domain of the device, and to explore the characteristics of float motion and the variation of wave energy absorption with time under different control strategies. The accuracy of the state space model substitution method is verified by comparing the results in the frequency domain, and the mechanism of the four linear PTO force control methods is further studied. Then, the time domain simulation model is used to study the influence of nonlinear locking control method on wave energy absorption. The results show that the latchup control can improve the speed of WEC and increase the wave absorption energy on the basis of effective control. At the same time, reactive power is not generated, but the output of energy under locking control is discontinuous, which requires that PTO has a short-term energy storage device, which is difficult to achieve in direct drive system. In order to accord with the actual situation, a stop system is added to the time domain simulation model to constrain the maximum displacement of the float. The results show that the stopping system can control the displacement amplitude of the device well. However, when complex conjugate control is used, the required PTO force will be further increased. Finally, under the premise of ensuring the economy and feasibility, using the frequency domain analysis method, considering the use of PTO effective control as the control strategy, for different float shape parameters, discuss the mass, radius, The influence of cone angle and shape on the hydrodynamic performance and wave absorption efficiency of the device provides a reference for the selection of wave energy conversion device.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P743.2

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