新型岸式波浪能发电装置

在对江河水能的利用上,目前主要是通过筑建大坝提高水位,利用水的势能来发电,其能量利用形式单一。波浪的运动分为水平和竖直两个方向,其对应着两种不同形式的能量。针对这一特点,在对江河沿岸波浪运动情况进行了调查和分析后,设计出一种以直线发电机为基础的新型波浪能发电装置;对两种不同形式的能量分别进行收集,并对其具体结构和工作原理作了详细描述。该发电装置利用波浪在水平方向的运动推动挡板水平运动,利用波浪在竖直方向的振动带动浮子上下运动,由传动装置带动直线发电机的线圈和磁铁反向相对运动,从而产生电能,实现对江河沿岸波浪能的充分利用。     

基于WFT的直驱式波浪能发电系统自抗扰功率优化控制

实际输入海浪的不确定性,导致直驱式波浪能发电系统工作环境中的噪音点多,传统控制策略控制效果不佳,输出功率低。文章通过分析水动力结构模型与直线电机模型,构建了等效电路;采用加窗傅里叶变换离散化不规则激励,获取频域主导激励分量及波浪能发电系统最大功率捕获条件,以确定最佳电磁力;基于d,q轴电流环矢量控制模型,设计了自抗扰控制方案,降低了激励输入噪音的影响,保证了电流跟踪效果。仿真结果表明,自抗扰控制策略的跟踪效果与滤波效果较好,抗干扰能力较强,系统功率输出优化效果明显,鲁棒性强。     

基于直线电机波浪能发电的制氢设计研究

波浪能是海洋中蕴含的品味最高的能源之一,捕捉波浪能进行发电是目前各国研究的重点。由于现有技术存在发电功率小、电压与电流变化大、传输困难等问题,波浪能发电难以并入陆地电网。文章提出一种系统设计,将波浪发电与海水制氢进行有机结合,可使波浪能电力就地电解海水制氢,为波浪能开发利用提供了一种新的思路。     

基于激励力预估的直驱式波浪发电系统功率优化

为提高不规则激励力工况下直驱式波浪发电系统的功率捕获能力,基于变分法给出最大功率提取条件,求解得到对应的理想电磁力。结合电机-水动力模型,设计滑模观测器,由Lyapunov函数证明系统稳定性,预估未知波浪不规则激励力输入。以理想电磁力为参考输入,采用空间矢量控制策略跟踪系统期望电流信号,实现最大功率输出。仿真结果表明,所提方案预估精度高,在模型失配时也有较好的鲁棒性,系统输出功率更高,可在线检测激励力,提高复杂海况下系统波能转换率。     

波浪能发电装置能量转换系统多级负载试验

根据波浪的特点,设计了一种应用在波浪能转换装置上的多级负载系统。对安装该系统的鹰式波浪能转换装置,按照功能和能量转换两种分类方法介绍机构组成和工作原理,并对液压系统的多级负载系统的设计进行了描述,包括系统的元件、试验原理及方法,最后通过试验对系统进行验证。试验结果表明,多级负载系统设计合理,能高效合理地利用及转换液压能。     

直驱式波浪能发电场的布局优化研究

文章研究了直驱式波浪能发电场的优化布局问题。将直驱式波浪能发电装置简化为地形,利用Mike21软件计算波浪能发电场内的波浪分布,进而将其作为波浪能发电场电气模型的输入,仿真获得波浪能发电场输出功率。在此基础上,基于波浪的传输特性,对波浪能发电场内各发电装置进行优化布局,以保证发电场的平均输出功率,同时改善功率输出的波动性。得到优化布局方案后,分别在规则波和不规则波两种情况下验证了方案的有效性。     

一种漂浮式波浪能发电装置的实验系统测试与研究

设计了一种漂浮式波浪发电实验测试装置,并进行一些必要的测试和评估。对系统在不同负载下的工作状态进行测试,研究液压系统各点压力变化情况以及发电机随负载变化的性能曲线。通过计算得到各环节的效率,结果表明,装置的机械部分和液压部分的转换效率可分别达到79%和95%,装置总的转换效率略低,一般约为18%。同时,分析了实验装置存在的主要问题及进一步的研究方向。     

直驱式波浪发电系统功率优化鲁棒控制

为应对海洋复杂波浪环境,改善不规则激励力下直驱式波浪发电系统的功率捕获效果,降低参数变化影响,建立水动力和直线电机模型,采用线性二次型调节器方法设计系统状态反馈,通过控制代价方程中的权重矩阵,权衡系统输出功率、运动部件位移和速度三者之间的关系;计算理想电磁力,得到q轴期望电流跟踪值。根据系统摄动数学模型,将控制器设计问题转化为H∞鲁棒控制标准型问题,通过选取适当权函数求解控制器参数,增强系统抗干扰能力。仿真结果表明,在浮子位移和速度受限制情况下,当系统模型存在参数摄动时,所提控制策略系统输出功率更高、鲁棒性更强,可较好地应对复杂海况,提高波能转换效率。     

双浮体—棘轮式波浪能发电装置

简述了一种新型的波浪能发电装置,其特点是利用两个浮体因波浪的波动而产生相对倾斜来收集波浪能,采用两个反向棘轮和一对链轮组,将往复运动转换成旋转运动,再带动发电机发出电力,是一种结构简单,造价低廉,容易实施的波浪能发电装置。     

基于单摆和拾振弹簧的漂浮式波浪能发电装置研究

针对漂浮式波浪能发电技术,提出一种采用单摆和拾振弹簧结构的新型波浪能发电装置.基于汉密尔顿能量定律建立该装置的两自由度运动模型,通过有限元分析得出单摆的运动规律,再根据单摆的角位移和电磁感应定律建立输出电动势模型.研究结果表明:在正弦振动激励下,通过拾振弹簧结构可有效增大单摆的转动角度,从而提高装置的输出电压;当波高为...     

Conventional and TFPM linear generators for direct-drive wave energy conversion

The archimedes wave swing (AWS) is a system that converts ocean wave energy into electric energy. The goal of the research described in this paper is to identify the most suitable generator type for this application. Of the conventional generator types, the three-phase permanent-magnet synchronous generator with iron in both stator and translator is most suitable, because it is cheaper and more efficient than the induction generator, the switched reluctance generator, and the permanent-magnet (PM) generator with an air-gap winding. The paper also proposes a new transverse-flux PM (TFPM) generator topology that could be suitable for this application. This new double-sided moving-iron TFPM generator has flux concentrators, magnets, and conductors on the stator, while the translator only consists of iron.     

Shape optimisation of floating wave energy converters for a specified wave energy spectrum

Ocean wave energy is one of the world's most powerful forms of energy and the energy density in ocean waves is the highest among renewable energy sources. Wave energy converters are employed to harness this energy and convert it into usable electrical energy. However, in order to efficiently extract the energy, the wave energy converter must be optimised in the design stage. Therefore, in this paper, a methodology is presented which aims to optimise the structural geometric configuration of the device to maximise the average power extraction from its intended deployment site. Furthermore, a case study of the Atlantic marine energy test site, off the west coast of Ireland, is undertaken in order to demonstrate the methodology. Using the average annual wave energy spectrum at this site as the input, the optimum structural geometric configuration was established, along with an analysis of the optimum configuration for different radius devices. In addition, the optimum damping coefficient of the PTO mechanism is determined and the total mean absorbed power for the structure at the site over the entire scatter diagram of data is calculated.     

具有波浪能转换功能的浮式防波堤性能研究

文章对具有波浪能转换功能的浮式防波堤性能进行评估。根据有限元空间离散法和VOF技术建立二维数值波浪水槽,模拟波浪和浮体之间的相互作用以及浮体的运动,同时记录浮体前后的波高,讨论浮子尺寸和阻尼系数对波浪透射系数和波浪能提取效率的影响。结果表明:波浪透射系数随着阻尼系数的增加而减小;在文章研究的浮子尺寸范围内,最大能量提取效率和最佳阻尼系数都随着浮子尺寸的增加而增加。     

A novel direct-drive ocean wave energy extraction concept with contact-less force transmission system

This paper describes the design and testing of a new rotary direct-drive ocean wave energy extraction system. The device employs a contact-less force transmission system (CFTS) to couple a float to the power take-off (PTO) mechanism made up of a ball screw, unidirectional clutch and a permanent magnet generator. Comprehensive simulation, design and testing of both the force transmission system and the ocean energy extraction system are presented along with preliminary wave flume test results of the buoy in irregular waves.     

Modelling,control and Pontryagin Maximum Principle for a two-body wave energy device

Frequency-domain analysis is applied to a wave energy device composed of two coaxial axisymmetric bodies. For each frequency optimal damping coefficient values which maximize absorbed power are obtained. Several displacement amplitude restriction scenarios are considered. A stochastic model to describe the device’s behaviour in irregular waves is developed. Optimal mechanical damping and spring coefficients are computed. Considering different sea state conditions, probability density functions are defined for relevant parameters and time-averaged absorbed power values are obtained.A time domain model is also developed for the device. A non-linear power take-off mechanism configuration, consisting in a hydraulic circuit with low-pressure and high-pressure gas accumulators, is devised. Time-averaged absorbed power is maximized in terms of characteristic mechanism parameter. A sub-optimal method of phase control by latching is applied to the device in order to improve its performance. Analytical development of Pontryagin Maximum Principle is used to establish an algorithm for device’s control.     

漂浮式波浪能发电平台船艏楔形角及浮子质量的优化研究

基于漂浮式波浪能发电平台,通过对船艏楔形角及浮子质量的优化,以提高漂浮式波浪能发电装置的波浪能采集效率。对发电船及浮子阵列部分建立了数值模型,进行了相关参数设置及有限元网格划分,采用水动力分析软件AQWA对该模型进行了水动力时域仿真模拟,分析讨论了不同船艏楔形角和不同浮子质量对波浪能采集效率的影响。结果发现:沿波浪的传递方向,各浮子的采能效率依次减少,并且减小的幅度逐渐增加;综合考虑该平台状况和波况,浮子质量越小,船艏楔形角越大,波浪能的采集效率较高。     

Structural integrity of a direct-drive generator for a floating wind turbine

In this work, the suitability of a direct-drive radial flux permanent magnet generator is examined as a probable drive-train candidate for a stepped-spar floating wind turbine system that supports a 2 MW downwind turbine. The suitability of the generator is assessed based on the structural integrity of its design (i.e., the stability of the air-gap between the rotor and stator) in response to the nacelle motions and its possible design implications on the overall system. Air gap deflections due to structural deflection and bearing tolerances were examined independently. The nacelle motions are obtained from experimental and numerical investigations on a 1:100 scale model. ANSYS suite is used to estimate the structural deformations of the generator and the changes in the air-gap distribution. Also, a simplified analytical model is used to compute the resulting changes in flux density and force distribution along the rotor periphery. The analytical model is also validated by 2D magneto-static simulations by utilising Finite Element Methods Magnetics software (FEMM).Preliminary results suggest that, if the nacelle accelerations are limited to 0.3 times the acceleration due to gravity (g) and the motion response cycles are below the fatigue limit, the air-gap stability of the generator is more sensitive to magnetic forces. Contributions to air-gap eccentricity from shaft displacements can be limited if the bearing supports can be designed for high stiffness. This also confirmed the adequacy of the platform design. The results also emphasise the need for air-gap management when designing direct-drive generators for floating wind turbines. Two methods are investigated as potential solutions to limit the maximum air-gap deflection to 10% level. The method of increasing structural stiffness led to a structurally unfavourable design that could potentially affect the stability and resonance properties of the system. The method of increasing the design air-gap led to a structurally more favourable design, although this meant an increase in magnetic material and hence the costs. Thus, implementing direct-drive radial flux permanent magnet generators for floating wind turbines is challenged by the difficulty in achieving optimal weight and costs at acceptable performance without compromising the air-gap tolerances. There is a need for an amendment to design standards to recognise the design challenges of Floating wind turbines.     

An integrated system of the floating wave energy converter and electrolytic hydrogen producer

The amount of energy produced now by the world community and that of energy flows caused by natural phenomena demonstrates commensurability of both power sources. Power production based on the conventional technologies is accompanied by environmental pollution, greenhouse and overheating effects resulting in biosphere degradation. It is apparent that the most intelligent solution of the problem of power production growth is the development of environmentally compatible power system using the regional renewable power resources. A system consisting of sea wave energy converter and electrolytic installation for hydrogen production is under consideration in this article.A potential candidate for wave energy conversion is an offshore Float Wave Electric Power Station (FWEPS), which is in the development stage. The second component of the system is the hydrogen producing facilities based on sea water electrolysis. Hydrogen as an ecologically safe fuel can be used in different branches of economy. The tentative studies showed that direct sea water electrolysis is technically feasible and is a perspective procedure for an environmentally-clean commercial production of hydrogen and associate products.Real performance of the system components allow to treat it as realizable.